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The Craftmans Shop => New from Old => Topic started by: awemawson on March 09, 2020, 08:22:09 AM

Title: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 09, 2020, 08:22:09 AM
As some of you may know it has been my intention to get my 100 KVA induction furnace back into a working state. It was all set up and functioning before I moved house nearly 13 years ago, but since then it has been tucked away in the fire proof room I built specially for it when the workshop was erected. Other things have taken priority and it's never been re-commissioned.

Back in Bromley before I moved, I powered it from a 100 KVA Agrecko diesel generator sat at the bottom of my garden, and as here I have a large enough incoming 3 phase supply (160 amps per phase) I sold the generator to fund building works.

Now, so many years later I am loath to slap it across the incoming mains, as if things have deteriorated over the time in storage it could cause considerable nuisance to the local community when I trip the local over head supply. Hence buying and re-building another generator described here :

https://madmodder.net/index.php/topic,12989.0.html

Initially I had intended to house the generator in a 'lean too' extension that we call the stable on the opposite side of my workshop from the fire proof room, but this has the disadvantage of being quite a way away, hence long expensive cable, and a bit remote to shut down in an emergency. Also the floor slopes somewhat and is rather rough concrete.

Investigating small containers / lorry backs / freezer rooms / concrete sectional garages to place in a bit of ground actually next to the fire proof room they all were discounted for one reason or another - mainly cost.

I then had the bright idea to buy a three axle 'plant trailer' allowing me to push the generator into place on this bit of ground, weather proofing it by building a steel sheeted  frame over it - trailer described in this thread :

https://madmodder.net/index.php/topic,13086.0.html

The shine came off that idea when I costed the metal work for the cover and it was coming out at over £600, so this morning I started investigating the cost of cabling (massive cross section) as I reasoned that with a bit of ingenuity I could extend the Emergency Cut Off circuit into the foundry itself.

Now I knew that I had some (short I thought) flexible 5 core 35 mm '07RN-F' umbilical cords already made off with massive male and female 'Commando' plugs and sockets from the original installation but had no idea how long they were. If I bought some more I could perhaps wire the generator across the back wall of the main workshop. Now this stuff is  £26 per metre so I didn't want to buy more than needed.

Having wrestled the coils from whence they were stored (on top of the CEIF driver box - oh boy are they heavy!) It turns out that I have a 10 metre and an 18 metre length - a really excellent find as it's enough without buying more  :thumbup:

My friend Graham (Seadog) came the other day and we were discussing the furnace and looking at pictures that I'd taken back in 2005 of it's internal electronics, and to my absolute HORROR I noticed that there is a 3.6 volt Lithium battery in a holder on the main board that presumably retains some needed parameters, and is now well over 15 years old  :bugeye: I have no idea what is RAM  retained or how the parameters are set, so this could be a show stopper as I doubt information is around on these rather rare animals.

Needless to say we shot out at a great rate of knots, moved things about so doors could be opened, and AMAZINGLY the battery STILL measures 3.6 volts  :clap:

So the show is still on - phew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 09, 2020, 08:28:48 AM
I think that the next thing to do is get the chiller working - this keeps the water cooling jacket cool for the internal high power electronics in the blue box, and also that surrounds the drive cables for the actual induction coil that is wrapped around the crucible.

I still have an access issue in that space - things have to go, so if anyone wants the huge BOC TIG welder (red box) and the Bridgeport chip tray (on top of the chiller) they can have them for free if they come and collect.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on March 09, 2020, 10:36:04 AM
Hi Andrew,
Looking forward to this thread! Maybe you'll have a pour scheduled around Christmas! Knowing you, you'll have it up and running well before then but I'd love to see it in operation!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 09, 2020, 10:58:27 AM
Matthew good to have you along - oh believe me I too would LOVE to see it working after all these years  :clap:

It's a totally illogical thing to do - I got the Induction Furnace because my neighbour at the last place built a house in the bottom of his garden so I ended up with someones kitchen next to my oil burning smelly foundry.

I moved so that I don't have such problems being a bit more isolated here (as you know) so logically I should really have abandoned this furnace and made another oil fired one but the pig headed bit of me is determined to get it going again.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on March 09, 2020, 11:16:59 AM

It's a totally illogical thing to do. What has logic got to do with all this? More fun!


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 10, 2020, 11:04:53 AM
I put the BOC Transtig  350 on Facebook Marketplace for £1 and not surprisingly had about 20 replies in the first 10 minutes and it was collected within an hour of listing by a very genuine local lad setting up his workshop.

Result  :thumbup:

I can now get at the front of the Flowcool chiller to investigate it AND welder chappie is a happy bunny so a win / win situation all round.

(That trailer went on eBay this morning so fingers crossed - Bridgeport chip tray still waiting for a new home)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 11, 2020, 07:41:06 AM
So having disposed of the BOC Transtig - all 200 kg of it - I could now get at the Flowcool chiller to try and evaluate how much it has suffered in storage.

Answer - there is quite a bit of rusting from condensation on the lower - perhaps 12 inches - of it, and quite an infestation of spiders evidenced by some impressive webs. So long as the actual motors / pumps / etc have survived it 'should' be OK but I want to do quite a bit of clean up before I introduce it to electrons at 415 volt three phase !

As I recall, (and I need to refresh myself on this) there is an internal water tank open to atmosphere (with a loose cover) that is cooled by an enormous 'fridge type sealed compressor. There is (I think) a heat exchanger immersed in the tank that holds the fluid that is externally circulated by a large multi-stage pump in the base of the unit. Air is drawn through large filters on the sides, passes over the refrigerator radiator and out to atmosphere through the top of the unit.

So on the rear there are four water ports:

A/ Flow and return for the chilled water that keeps the bits of the Induction Furnace cool
B/ Top Up mains water to allow for evaporation of the tank, controlled by a simple float valve (Like a Loo cistern)
C/ Overflow from tank in case float valve misbehaves.

The whole lot is controlled by a temperature controller and a bunch of relays, transformers and over load cut outs housed in a cabinet on the front.

I can't get too involved in going much further today due to other commitments, but I want to give it a good blow out with an airline, then set up an air blower into the electrics to try and reduce the moisture before feeding it power  :bugeye:



 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 12, 2020, 06:16:01 AM
This morning I rigged a long airline extension to blow off the majority of the cobwebs and rust flakes from the Chiller.

To my horror I found that I was spraying significant amounts of water with the air - the vertical drop of my air line system that I was using to connect the air hose extension hadn't been used since I installed my total air drying kit, and must have previously accumulated water. Blasting air to waste quickly disposed of it, reverting to delivering dry air letting me carry on.

I'm pleased to report that a basic electrical safety test passed. Good earth bonding to the chassis from the plug & lead, and no measurable leakage to ground for the connections to the compressor, pump, fan or system transformer. NB I was measuring to earth from the outputs of their respective contactors, so effectively directly to their windings.

Next hurdle to overcome is aquatic. The reservoir tank that holds the main heat exchanger needs filling for the beast to work. I have no mains water yet plumbed to this room, and the tank top is too close to the base of the control cabinet to pour in from a container - perhaps 2 inches - it could be done with a hose, funnel and bucket but the other issue is that I need to be able to drain the tank to move the chiller as working is done on it and around it, but as yet I've not identified a drain plug. I must have done in before moving it here, but for the life of me cannot remember how - maybe an external pump?.

The the flow and return pipes that come from the main pump need filling with water and making into a circulatory loop system. If I don't do this there is a probability of destroying the pump ceramic seals if run dry.


. . . still it's progress of a sort  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 12, 2020, 12:05:22 PM
So next I rigged up a loop for the flow and return and primed it with water, and then pumped several buckets full of water into the main tank - all good so far.

I then connected up to 415V, crossed my fingers and switched on. No dramas and an indication on the temperature control of current tank temperature. Still all good until the compressor - that BIG blue compressor lump switched on, and the MCB for the 415v tripped. OK it's only a 16A 'B' rated one. I upped it to 32 amp, again a 'B' rating as that's all I had - still trips. Without the compressor running the load is only 5.7 amps per phase.

Pushing my luck I installed (as a temporary measure) a 50 amp 'C' rated breaker being the only spare 'C' that I had to hand. Works fine - running current is about 15 amps per phase AND the temperature is dropping. It got down to 7.1 degrees when I heard the dripping of a significant leak  :bugeye:

Main pump seal is FUBAR so I started siphoning out the tank, but a fair amount is going to end up on the floor to evaporate  :bang:





Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Will_D on March 12, 2020, 08:00:18 PM
Hi Andrew,

You make my "little problems" seem totally insignificant!!

Keep up the great work, "Nil Illegitimum, Nil Carborundum"

Regards to the pigs!!

Cheers

Will, Malahide.ie
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 13, 2020, 03:38:37 AM
Thanks for the encouragement Will, I’m not looking forward to rolling about on the floor in a confined wet space removing that pump this morning.

. . . But it has to be done!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 13, 2020, 06:30:51 AM
As anticipated, rolling about on the floor getting the pump out was not my most enjoyable experience, but, never mind, THE PUMP IS OUT  :thumbup:

Leaving a powerful fan blowing in the area overnight had done a remarkably good job evaporating most of the water. The plastic pump inlet coupler unscrewed with relatively little trouble but this was not so with the one on the outlet. I tried every trick in the book - gentle tapping, gentle warming, and increasing levels of violence, but it was obvious that it wasn't unscrewing without breaking (plastic remember). I suspect that some of the solvent glue used to assemble the pipework had inadvertently got into the thread of this fitting. Angle grinder and hack saw removed it allowing me to get on disconnecting the electrical connections and unbolting the motor base from the chiller chassis.  The four bolts were fortunately stainless, not galled solid, and not too tight - lucky as access underneath is challenging.

Having got the pump on the bench and now able to read it's label it turns out to be a Grunfos CH4-60. Options are replace (at least £500 with the VAT ) or get a seal kit (£143) Interestingly the one for Glycol cold water version is cheaper than the standard one  :scratch:

I will have to replace a bit of the existing plumbing - working back from a stub of original 40 mm plastic pipe, the branch leads to a 1/2" BSP re-circulation valve (controls pressure) and to the pump that is standard 1" BSP so simple enough.

Time to go and get changed - covered in concrete dust  - yuk !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 14, 2020, 07:39:06 AM
With the spare parts not yet to hand I'm not going to dismantle the pump, however I wanted to make sure that I can when the time comes, so am applying PlusGas to all the various bolts and screws. All now move except the two short pan head screws holding the fan cover, hopefully a bit of soaking will loosen them but if necessary they can be drilled out.

Removing the 1" BSP plastic pipe screwed into the outlet revealed a curious mangled spring which is part of the ceramic seal assembly which explains why the leak was so gross - usually they just weep when they fail.

I turned off the old plastic joiner and threaded the pipe 1" BSP to raise the knuckle joint above the electrical connector box.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 14, 2020, 11:29:48 AM
Of course the inevitable happened, and one of the fan cover screws sheered off, and the other was so mangled as not to be considered worthy of being used.

Simple matter to mount up in the Bridgeport, drill out and re-tap M4 and replace with stainless button cap screws. It is possible that had I left the PlusGas a bit longer they might have loosened, but I think not, and I wanted access to the fan to be able to rotate the pump and get a better look at that curious displaced spring. It rotates with the pump shaft and I'm fairly certain that it is the one that presses the two halves of the 'mechanical' ceramic seal together to make a leak proof joint.

Hard to work out how it got into this state - I can only think that the pump has ingested something that got caught on it so hopefully when I dismantle the six stages of the pump there won't be more damage to contend with  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on March 14, 2020, 08:16:40 PM
It's good to see you're under way with this project Andrew. Looking forward to the inaugural firing up  :zap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 15, 2020, 08:53:31 AM
Looking forward to the inaugural firing up  :zap:

You and me both Graham, but a long way to go yet I'm afraid !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 15, 2020, 04:46:02 PM
I've just been watching Martin Zero's video on YouTube exploring James Brindley's 'siphon tunnel' diverting water from the River Irwell  under itself to drive mine pumping equipment in the 1700's - fascinating video, but he used an innovative way of getting his camera into a dangerous place (strapped to a model radio controlled tank!) - and it set me thinking . . . .

I want to investigate inside the 'chilled water storage tank' that feeds the leaking pump - I have an endoscope camera - will it work ....  :scratch:

Well the answer in NO - focal length is quite wrong and cannot see anything but close ups of individual elements of the finned radiators :bang:

However - just the job to take a proper look at that broken spring on the ceramic pump seal - so here is the video with the endoscope poked down the outlet port of the pump:





Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on March 16, 2020, 03:08:53 PM
I watched Martins video too, fascinating stuff! On the pump, looks like the spring has caught on the back of the seal spinner and got unwound, not a failure I have seen before, and I have done a few pump seals! There is usually a stainless washer at either end of the spring to stop it catching.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 18, 2020, 10:23:28 AM
The pump motor cowl and base plate were quite rusty so I decided as the seal parts still hadn't arrived, I'd grit blast them and give them the usual zinc rich primer and satin black top coat, to make them less offensive to the eye as they sat on my bench.

I've recently made two alterations to my grit blaster that have made it significantly easier to use:

 - Firstly I've fitted a long thin axial fan (ex photocopier) to blow across the cabinet window to remove the condensation from my breath that was a major obstacle to seeing what I am doing.

 - Secondly I've plumbed my 104 CFM huge 18 kW Hydrovane into my air system so that I can blast at full pressure continuously without having to pause every now and again for the smaller one to catch it's breath.

All went well and paint is now drying, but guess what arrived whilst I was blasting - yes, the seal kit  :thumbup:

So the next job is to dismantle the pump in a controlled fashion to keep the myriad of pieces in the correct order for re-assembly. Six stages each of which have a housing, an impeller, a gasket and two spacers.

. . .but first I must study the instructions  :coffee:

(Various plumbing bits yet to turn up so no huge hurry)




Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 18, 2020, 11:24:23 AM
Opening the seal instructions attached to the (vastly expensive) seal kit, there is no illustration of the specific seal used on the CH4-60 - there are illustrations of similar pumps but the ends of the spring have outward facing pegs on the end turns, whereas the kit and the pump that I have has a plain spring. So the location methods obviously differ for the bit that rotates.

It probably will be perfectly obvious when I dismantle it, but my experience of these pumps tell me it's best that you have the CORRECT drawing before bits fly in all directions (*)  :clap:

Grundfos 'are surprised' and are trying to find a copy of the correct illustration to email me so I won't pull it apart at the moment.

Meanwhile the paint has dried on the end cover and mounting foot so they have been temporarily re-assembled to get them out of the way until that drawing arrives. I must say the pump looks cosmetically far better than it did :thumbup:

(* My first introduction to Grundfos pumps was when one failed in one of my Launderettes, and I got a panic and embarrassed call from the engineer who did my maintenance to say he'd dismantled the pump to replace the seal and couldn't work out what went where. I was presented with a plastic tote box with an entirely dismantled CR8 (8 stage) pump and spent the next couple of hours working out what went where - a baptism of fire - or water you might say!)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 18, 2020, 01:57:45 PM
So casting all caution to the wind I started dismantling the pump.

The first stage casing was firmly stuck to the inlet casting, somebody has used a thread lock I think. Gentle heating and a tap or two eventually got it loose to the stage you see in the first picture.

The seal / spring assembly is now exposed and actually it turns out the original definitely had bent over ends of the springs going into locating holes, whereas the kit does not, so more investigation needed.

. . .but supper calls . . . !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 18, 2020, 04:54:14 PM
I got the old seals out. They are quite different from the replacements in the way the spring is compressed and rotated.

The original has the ends of the spring protruding and engaging in a hole in the other parts, with quite a compact arrangement to house the shaft O ring. The replacement has a plain spring and pressed metal parts that is considerably larger. I can see that it probably fits, and may be an upgrade but there is no mention of the difference in the instructions, nor does it mention why there is a black and a green version of both O rings. However the original had green so that's what's going back in!

(Google tells me green O rings are Hydrogenated Nitrile and are intended for high temperatures and stresses!)

Perhaps I should explain that the static part of the seal is sealed to the motor casting with a large thin O ring, and the rotating part of the seal is sealed to the shaft with a small fat O ring. A ring clip sits in a grove in the splined shaft holding the assembly together as the rest of the pump is assembled which gives the final compression to the spring.

Everything needs a good clean up before reassembly - there is a distinct 'tide mark' where it has dried out down to just below the shaft level, leaving a rust and debris conglomerate that needs to be removed from most of the impellers and the end housing to ensure that it doesn't get pumped round the system when it's back together - oh joy !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 18, 2020, 06:18:47 PM
It seems that ceramic / mechanical seals are a very complicated but fascinating subject. I came across this treatise from Grundfos that I found very informative. Amusingly it illustrates the very pump I'm working one on one of its plates.

A bit of reading for those of you self isolating as I am !


https://api.grundfos.com/literature/literature/Grundfosliterature-5768950.pdf
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on March 19, 2020, 04:06:54 AM
Whoever wrote that paper did a brilliant job of demystifying the science and engineering and presenting it in a very readable and easy to comprehend manner. :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 19, 2020, 07:25:28 AM
Yes it certainly sorted out my understanding of rotary seals!

So now the big clean up begins. Frankly it's not surprising that the spring and seal failed - all inner stainless steel surfaces are covered in a light coating of deposited rust, as are the two end castings, and there is a 'tide line' of something very varnish like that has set rock hard.

I gently grit blasted the inner surfaces of the cast iron inlet and outlet ports, masking up the motor, seal area and shaft to avoid damaging them. It worked quite reasonably, but I had to hand scrape some as I didn't want the blasting pressure too high to avoid ingress of grit where it wasn't wanted.

I'd intended to continue gentle low pressure blasting of the stainless steel pump vanes and housings, but it seemed a shame to lose the polished surface even though I don't suppose it would interfere with the pump operation. Experimenting with a specialist corrosion remover that came with my Wire CNC EDM  machine it worked extremely well apart from the varnish like deposit, so at the moment all the vanes, housings and spacers are soaking in a washing up bowl of hot water and Altrans (by DEB) that is mainly phosphoric acid with a wetting agent added  -  I had to top up with neat phosphoric acid as the Altrans was insufficient to cover everything.

Probably leave them there for a few hours to cook in their own juice.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on March 19, 2020, 08:20:30 AM
Very interesting read.
It describes the precise failure mode that you have, Andrew. A torque transmission seal where, at some time or other, the seal faces have bound together and, when the pump has been restarted, the stiction has been sufficient to unwind the spring a few turns thereby causing its failure.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 19, 2020, 11:05:14 AM
Yes Seadog and reading that article it seems using the spring is the later version, and the spare I've been supplied is the earlier one where there is positive drive from those pressed steel cups.

Well the kit seems to be compatible, anyway for better of for worse the pump is now back together - hoo-blooming-ray it's been a long time coming. I won't be able to test it's sealing abilities until the pump is re-installed, and that can't happen until the last of the plumbing arrives hopefully by the end of this week.



I assembled the O rings and seals with copious amounts of washing up liquid as a lubricant so no doubt it will froth a bit to begin with. But before that I finished the clean up of the internal components, and I must say they've shone up very well, far better than I expected  :thumbup:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on March 19, 2020, 11:31:00 AM
Hi Andrew,

It's good to see it going back together again! If there was a like button I'd use it! Are you planning on casting iron? Looking for ward to seeing it working!

Cheers, Matthew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 19, 2020, 03:27:34 PM
Matthew, at this rate I'll be glad just to get a bit of old steel bar glowing in the crucible !

Long way to go yet. Hopefully the Chiller will soon be sorted, but I need to start deciding on a layout in the foundry. Chiller needs  to be plumbed to the Furnace Driver which is then plumbed to the Furnace Body where the actual crucible is and all need heavy cabling and pipes and can't really be moved once set up. In the case of the Furnace Driver, which has the major amount of electronics in it, I need access to all four sides (all open up as panels) for testing in the initial phases.

As yet the foundry only has lighting wired in, I left the power side until I know where things are going to settle. Then somehow I need to move the 110 KVA generator into the stable over it's wonky floor, level it up and duct it's output across the back of the workshop into the foundry.

The foundry still has too much other junk in it for comfort. Some things such as the big pottery kiln are justifiable for lost wax burn out, but much else has to find another home. Trouble is it has accumulated junk over the years as it wasn't in use.

In there there is still the Hodge Clemco 'outdoors' grit blaster with it's crates of bits, a trolley mounted sheet metal nibbler, two rather nice beechwood foundry benches, two racks of shelves, two sets of oxy-acetylene . . . well you get the idea !

. . . so how long do I have to stay in isolation . . . . . . ?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on March 21, 2020, 12:19:08 PM
. . . so how long do I have to stay in isolation . . . . . . ?

Until all your projects have been completed for our entertainment and satisfaction!

Good Luck Andrew, stay Healthy!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 21, 2020, 01:22:34 PM
Thanks Phil. Loads more 'stuff' shifted from the Foundry building today (lucky that  I re-roofed that Portakabin a while back!) but still loads more to move but I need to find homes for it  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 31, 2020, 10:19:27 AM
So hoo blooming ray the long expected 100 mm length of 1" BSP threaded stainless pipe arrived today. Supposedly from Southern Ireland but it was wrapped in the usual 'I've come from China' packaging. - I reasoned that it must have been packed well over the 72 hours the virus can survive for so it was 'probably' safe.

This allowed me at last to do a dry assembly trial fit as I need to arrange the 15 mm pressure control back feed to the tank via the gate valve at 35.5 mm off the base. Once that was proven possible I was able to slice off the remaining bit of vertical plastic pipe with some confidence that I can bond onto the stub and still be able to get the pipes assembled. In practice the 15 mm pipe has ended up about 5 mm too low, but I think that there is sufficient flexibility in the system to accommodate that.

The Christmas Tree of plumbing has been assembled on the bench with Loctite 542 and once that is fully cured I can trim the last bit of the plastic stub and  solvent glue that on.

. . . slowly slowly . . catchee monkey  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 01, 2020, 05:03:11 AM
The Loctite 542 having cured I was able to re-assemble the pump plumbing in the chiller and make the solvent weld joint to the original plastic pipe. This itself needs to cure for 24 hours before I can fully tighten the various other joints and finally re-connect the motor and run a test.

I hope to heck that that seal works after all this faffing about  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 01, 2020, 08:16:59 AM
Confidence, confidence.... :thumbup:.      As Dennis said, ' it'll be alright on the night...'

Just dont forget....as I'm sure you won't....Dont run the pump dry!! Or bye bye seal... :doh:

Good luck..
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 01, 2020, 11:15:11 AM
John the seal is laced with washing up liquid at the moment and I will initially put just a bit of water in the tank and turn the pump by hand using it's cooling flange before any power is applied.

First thing is to slowly fill the tank and watch for static leaks, and to that end I've just resurrected a hose pipe point not too far away (O ring seals totally crunchy after a few years in direct sunlight), and I've reconnected the motors wires and bolted it's flange down.

So if I can persuade her tomorrow it'll be wife on the tap and me with hose in the tank 20 yards away yelling STOP  :bugeye:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 02, 2020, 05:49:15 AM
So some good news and some rather bad news :(

I filled the tank - no leaks and all seemed well. I spun the pump by hand by means of its cooling fan - still OK.

Then I applied 3 phase to the machine - sure enough pump running, and the controller showing current water temp - the main cooling  fan then started and I noticed that it was spinning the wrong way - warm air should exhaust at the top, and be drawn through filters at the sides, but it was going the other way. Checking the Grundfos pump, it too was spinning the wrong way so obviously a phase reversal. But by this time the cooler had  reduced the water temperature to 5 degrees.

So I reversed two phases and now pump  and big fan now spinning the correct way - the compressor however made a funny noise and tripped its breaker  :bang:

It does look at the moment that the compressor has died, and this could be terminal for the entire project due to cost. I've walked away from it to allow my head to clear - a quick look on eBay reveals a few similar but not identical compressors starting at £250 but even if I got one I'd need it to be installed and re-gassed. Installation would be far from easy as it is tucked away in a cramped space.

. . . . . one step forwards . . . five backwards  :bang:

As I filled the tank the float for the water top up inlet valve, that I had noticed was on the base of the tank, floated up and I ws able to recover it - it looks as though it should just snap back into place but that's the least of my problems at the moment.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 02, 2020, 06:03:51 AM
Oh Dear!...This is not good....Yet you've come so far...

Is it worth getting your compressor 'fettled' ? versus the price of a replacement of dubious quality? Do you know anyone in the refrig game that could connect and regas as a home job?

Here's hoping you can rescue it... :dremel:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 02, 2020, 07:44:01 AM
John it's all up in the air at the moment - it sounds as though the motor itself has blown up and of course they are a sealed unit.

I >MAY< try reverting to the reversed phases briefly as it was working then ! But at the moment I'm giving it a wide berth !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 02, 2020, 08:56:56 AM
Well I did revert to the phases the other way round - still kaput as you might expect.

Intriguingly two phases are drawing about 90 amps before the breaker trips, and the third phase is drawing no current  :scratch:

I think that it's 'proper sick' - shame it's a sealed unit like a normal 'fridge one (but on steroids!)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 03, 2020, 05:26:06 AM
A diy regas? Depends I think on what the gas is.

-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 03, 2020, 05:31:43 AM
A diy regas? Depends I think on what the gas is.

-Russ

If you can buy the gas...
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 03, 2020, 07:09:38 AM
You didn't state it explicitly, But I assume that when you first connected with the phases wrong that the compressor did work, is that correct?

If so it's strange that simply reversing the direction has caused it to fail.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 03, 2020, 08:26:37 AM
Graham I think the phase reversal was just co-incidence as the starting current was pretty massive. Not sure how these sealed units operate - this one is apparently a four cylinder model - but years ago it definitely worked with the phases connected such that the pump and fans were spinning in the correct direction.

Recently before it failed, and with the Grunfos pump and fans spinning the wrong way, the refrigerant unit was working and cooled the water tank from 8 degrees down to 3.5 degrees. So I'm not sure how the internal pump in the sealed unit works. Reading the manufacturers documents they are NOT sprinkled with dire warning re direction .

The internal motor has failed I'm sure evidenced by the enormous current it's drawing (90 amps on two of the phases!) so sadly it's a bit more than just re-gassing it .

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 03, 2020, 10:18:37 AM
That's really bad news, Andrew. I've no idea about the internals of this type of pump, but I'd assume they're a reed valve or something similar, so direction shouldn't be an issue.

I stand to be corrected.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 03, 2020, 10:43:29 AM
I understand that the sealed unit compressor / coolers have an oil charge and a gas charge within the envelope.

When I re-built the Grundfos pump there was a tide mark of 'something' that had dried to a hard varnish like substance (indeed I think that's what did for it's seal & spring) and I'm just getting this nagging doubt whether the immersed bit of plumbing in the water tank from the compressor unit has sprung a leak, released the oil into the water which over the years evaporated leaving the varnish tide mark.

This would of course explain the demise of the compressor (no oil) but if this is the case I'm surprised that it did actually chill the water and I was not aware of masses of  bubbling in the tank from an alleged leak.

. . . this is forensic engineering !!!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 03, 2020, 05:31:38 PM
I think we need to organise crowdfunding to keep this project rolling. You've come too far to drop it all now  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 03, 2020, 06:06:45 PM


) so sadly it's a bit more than just re-gassing it .

Sorry, should have been clearer. I thought you said you had found a replacement but regassing was the barrier.
Even though the replacement was not as ruggedly built,  given its likely use (ie, sporadic, not continuous as would be for say a cold store) would it be 'good enough'
Of course, original refrigerant (r12? ) may be illegal to work with without a licence, but later types seem to be available as diy.
Although not trivial...


-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 04, 2020, 02:27:29 AM
Graham, what a nice thought!

Russ, I don’t think sourcing a replacement equivalent unit would be too much of an issue apart from the cost. They seem to be north of £1500 new, and dubious used ones pop up starting at £250 /£750 mark though none are identical.

Before committing anything like that sort of money I some how need to get a bit of confidence that the rest of the furnace equipment is reasonably sound. I do remember that when the furnace driver was delivered I was able to connect it to one of the furnace bodies and get the electronics to ping and determine the resonant frequency. At the time I had no chiller and no high power 3 phase supply in fact I was running off a Transwave static converter off a 13 amp socket!  Obviously I couldn’t go any further without a massive power source.

So I think probably my next objective is to repeat that experiment.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on April 04, 2020, 02:47:44 AM
I think we need to organise crowdfunding to keep this project rolling. You've come too far to drop it all now  :clap:

I'm with you on this Seadog!


Before committing anything like that sort of money I some how need to get a bit of confidence that the rest of the furnace equipment is reasonably sound. I do remember that when the furnace driver was delivered I was able to connect it to one of the furnace bodies and get the electronics to ping and determine the resonant frequency. At the time I had no chiller and no high power 3 phase supply in fact I was running off a Transwave static converter off a 13 amp socket!  Obviously I couldn’t go any further without a massive power source.

So I think probably my next objective is to repeat that experiment.



 
This sounds like a good plan!! Looking forward to the results!!

All the best, Matthew.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 04, 2020, 04:29:36 AM
Ah. OK. I read your previous post as saying that a replacement was gbp 250 - 1500 is a different matter....

-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 04, 2020, 04:36:17 AM
Good to know that you are following along, frankly this is drawing on all my resources of enthusiasm and perseverance  :(

A fair amount of Googling and Youtube watching tells me that this style of pump does indeed use reed valves, and pistons driven on an eccentric so I'm pretty sure that direction of rotation of the motor IS irrelevant.

It also told me that there is a 'telltale'  to show the oil level which I eventually got to after much huffing and puffing (round the back down low very dark!). Now I can see 'something' in the tell tale window but am I seeing current oil level or an artefact from the level  as was some time ago - what makes me suspicious is that it doesn't seem to be horizontal  :scratch:

Laying concrete today so not more will be done I expect.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 04, 2020, 05:12:34 AM
It's identical in construction to the Ingersoll-Rand that I'm rebuilding, in that case. I suppose it's a pretty common design. I've never played with a compressor before so it was all new to me when I took the crankcase cover off.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 04, 2020, 05:24:04 AM
Absolutely following.

I've learned that 100kw induction furnaces are far more complex than I had ever envisaged...

You can't possibly give up until you have the next project on the go.



-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 04, 2020, 05:25:47 AM
Years back when I had my Moog Hydropoint and needed large volumes of compressed air I had a Prestcold 3 cylinder inline cold room compressor - the  integral 3 phase motor was too large for my converter to drive until I removed the cylinder head and took out the flat leaf valves for one cylinder - then it was fine ! That though was shaped more like a car engine with a crank shaft with three throws.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 04, 2020, 06:35:25 AM
Good to know that you are following along, frankly this is drawing on all my resources of enthusiasm and perseverance  :(

A fair amount of Googling and Youtube watching tells me that this style of pump does indeed use reed valves, and pistons driven on an eccentric so I'm pretty sure that direction of rotation of the motor IS irrelevant.

It also told me that there is a 'telltale'  to show the oil level which I eventually got to after much huffing and puffing (round the back down low very dark!). Now I can see 'something' in the tell tale window but am I seeing current oil level or an artefact from the level  as was some time ago - what makes me suspicious is that it doesn't seem to be horizontal  :scratch:

Laying concrete today so not more will be done I expect.

I must say it looks like a tide mark to me Andrew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 04, 2020, 08:31:10 AM
I fear that you are right Pete, but those that I've seen on Youtube being butchered open have oil in that is basically clear with a light grey tinge to it so I can't be certain.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 04, 2020, 09:14:22 AM
If the price of a drop in replacement is prohibitive, could you graft in a stand alone chiller unit?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mc on April 04, 2020, 11:08:09 AM
I must say it looks like a tide mark to me Andrew.

I'd agree.
I'd say the light silver mark around the lower edge of the glass is the machined lip the glass sits against, and you'd normally expect to see oil between the glass and metal.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 04, 2020, 12:45:22 PM
If the price of a drop in replacement is prohibitive, could you graft in a stand alone chiller unit?

John, the Flowcool IC120 chiller in which this compressor is housed IS a separate stand alone unit from the actual Furnace Driver itself - it's a darn great big box!

It draws 11 kW according to the specification, and provides 39 kW of cooling to the water so is quite a beast.Chillers like this are used in several industries - (injection moulding is one) and I suspect that sourcing a complete working second hand chiller of similar specification would be a better option than replacing the compressor if there is doubt about the integrity of the immersed plumbing.

The late and much lamented Mark McGrath spotted this one for me in an auction in South Wales back in 2006 - an auction that I won of course as I now have the beast. So if any of you know where I can lay my hands on another powerful chiller of similar specification don't be shy, shout out !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 06, 2020, 07:12:02 AM
So logically if I am to take this project any further I need to gain some confidence in the big blue box -the actual Furnace Driver that takes 415 volt at an unhealthy number of amps, and oscillates away driving coils round the crucible at several thousand amps  :bugeye:

To get it to 'ping' and establish the resonant frequency, which can be done without too much power I need to locate the four 'driver hoses' that connect the blue box to the crucible unit. They are not just hoses, they have very heavy bare fine strand copper wire threaded up them, and the chilled water is pumped down the hose to stop them melting. At least if I can get the 'ping' working it'll show if the electronics is at least still alive.

Now all the furnace ancillaries were carefully set on a pallet and plastic wrapped about 13 years ago and the pallet placed between my CH oil tank and my Red Diesel Bowser, and I've been dreading pulling bits off it  :bugeye:

Sure enough massive deterioration - pallet totally rotted away, plastic wrap eaten by vermin and quite a bit of rust in places - but today I pulled it all out and placed it on my loading dock for examination.

Some things are definitely beyond hope -

a/ A big low speed chest drill I used for mixing sand - too rusty to both with

b/ The water pipes from the Chiller to the Furnace driver - at least one eaten by vermin

c/ A asbestos cement mounting panel that adapted the driver hoses through 90 degrees - totally crumbled away

None of these are show stoppers - I have a second four way 90 degree hose panel that seems to be OK, the drill is no big issue and the water hose is just standard large bore reinforced hose and can be replaced
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 06, 2020, 07:25:23 AM
However I find that I have:

A/ Two sets of four hoses - a long set and a short set. At a first glance they look as though they may have survived

B/ A spare coil unit for the crucible unit - looks OK now I've removed the mouse nest !

C/ The big Grundfos pump that I used to circulate water round a 'Cold Bank' (a standard copper hot cylinder) - this may be OK - I had been careful to fill it with water to keep the seal moist and cover it with the small plastic header tank to keep the rain off the motor)

D/ Two tubs of high temperature cement - may or may not be OK

E/  Miscellaneous water fittings

F/  Furnace driver four way pipe  90 degree adaptor

The ends of the chilled water hoses can be re-used so they are not a total write off.

So next I need to do a proper assessment of the driver hoses for  electrical conductivity and water tightness.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 06, 2020, 08:03:28 AM
Inspecting the short driver hoses they are quite badly crazed but although I'll not use them ultimately with water under pressure, they will be OK for the 'pinging test' I think

The long set of hoses actually seem to have fared better - I've not completely unwound them but the bit's I've bent so far don't show the same crazing. This long set of hoses I made myself from brand new welding cable and 150 PSI 'Brewers Hose' so is probably a bit newer.

I'd forgotten that I also had a rigid set of extensions I'd made - heavy wall 3/4" copper pipe double insulated by two layers of flexible conduit which was a right pain all those years ago getting it on!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 06, 2020, 11:13:57 AM
I had words with a local refrigeration company today -  (I've used them before re-gassing an air drier compressor  so had one of the directors mobile number on my list ! )

Basically his conclusion is much the same as mine - the compressor is toast, the rest of the plumbing is questionable, and even given an (expensive) replacement compressor it will use gas that is no longer allowed  :bang:

. . .so it looks like a replacement total water chiller is the only logical way to go if the ping test works.

Meanwhile I re-palatalised all the ancillaries making sure the pipes needed for the ping test are on top and tucked them away in the tractor shed. Now if I'd had the tractor shed before they wouldn't have deteriorated - but I didn't  :bang:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on April 06, 2020, 06:20:22 PM
Sorry to hear that mate.

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: chipenter on April 07, 2020, 03:19:33 AM
Will it work with total loss cooling using water form your stream , I know it's 70 yards away but 150 yards of hose have to be less than a new chiller ? 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 07, 2020, 04:21:08 AM
Total loss probably would be OK, (especially as after that burst water main a few years back I have a private fire hydrant !) but my concern as I mentioned earlier is furring up of the internals.

One solution would be a heat exchanger immersed in a tank of water such as an IBC, where the tank is constantly being refreshed on a total loss system so the the water circulating in the furnace itself is always the same water

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 07, 2020, 07:34:18 AM
Seems like that could be enough for a proof of concept to prove that the rest of the system is functional.

Even direct flow for an hour or two would be ok?

-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on April 07, 2020, 08:38:27 AM
When I played with a big induction heater, having low conductivity liquid is the heater internals was important.  Gallons of DI water...  there were hose spirals that isolated the hot, high voltage bits from the grounded pump and cooler.  My levitation coils were on a separate cooling loop, and much less critical.

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 07, 2020, 10:03:47 AM
Yes this one has an odd four terminal feed arrangement to balance the coils to ground. I remember that when I installed new crucibles in each of the furnace bodies I had to make internal water connections to flexible tubing, but I couldn't use normal jubilee clips as the strong AC field induced currents in them that heated them up enough to melt the pipe ! I had to source special plastic clips to avoid the issue.

Today's objective was to clear enough 'stuff' from the foundry to allow me to choose one of the two furnace bodies, and get it close enough to the furnace driver for the hose / cable assemblies to reach.

Much 'stuff' was re-distributed causing havoc elsewhere but I did actually manage to achieve the objective AND leave enough space arround it and the driver unit to investigate further.

My two 'bodies' are:

 a/ A tilting one that pours into a ladle or direct to a mould

 b/ An inverting one where the mould clamps on top, and when the charge is molten can be inverted into the mould

I chose the inverting one simply as it was sitting on a base with castors and could be moved for inspection more easily - the other one is parked in the stable and no doubt will raise a few comments.

On a roll I decided to investigate the inverting body a bit. It has a clamping pneumatic cylinder that retains the mould on top, and another one that presses on a rack and rotates the entire body upside down - this later motion needs a bit of clearance around it and would easily remove  stray fingers.

Amazingly the pneumatics still seem to basically work albeit with a bit of hissing and wheezing!




 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 07, 2020, 06:44:10 PM
My word, that is a tidy shed  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 02:04:30 AM
As you know Graham, it was packed to the rafters, and totally impossible to work in.

. . . Something had to be done !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 10:28:45 AM
Today's objectives :  Wire up the 415 volt three phase input and  connect the furnace body ready for pinging

All very well, but the postman delivered the replacement bearings for my buffing spindle, the motor of which is in pieces on the workshop floor - so re-assemble with new bearings - it's only a 5 minute job.

Blooming thing took literally the whole morning. First assembly, greased the bearings, pressed them home, replaced the motor end bells, spindle locked solid  :bang: Slacken an end cap spindle frees up - have I put the crinkle shaft expansion washer in the wrong place  :scratch: Pull it apart, no washer in correct place, make sure bearings fully home - reassemble - still stiff - argh, beginning to loose the will to live . Dismantle for third time, examine everything, find a burr on one bearing retainer ring pressing inwards onto shaft - bung it back together, put it back on it's pillar - all OK except I've just lost an entire morning  :(

So I didn't get started on the furnace until this afternoon. First thing, pull it away from the wall on the pallet truck and unbolt all the doors - front one has keys, the other three although hinged are bolted shut, and the last panel is just bolted and not really removable as loads is mounted on it.

To get it out of my previous foundry, the main isolator switch operating handle, and the 125 A input socket had to be removed to get it through the door - but where are they? OK found tucked away inside behind panels, and at least I had had the foresight to label the phases  :thumbup:

Bit of a pain re-assembling them - one of the Nutsert bushes holding the input socket failed and is pretty well impossible to get at, so it's fixed with three out of four bolts, but OK for now.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 10:41:31 AM
So now on to the driver connections to the furnace body. There are four rubber hoses each with a heavy braided copper cable cooled by a water jacket - or they would be if I had a cooler !

Searching around I found that I had made sketches back in 2005 when I got this beast to better understand how it interconnects.  Basically there are two coils (actually one centre tapped) with a blockage for water where they join. The coils are wired in parallel and give about 13 micro-henries of inductance.

There are two water circulating paths.

OK how do I connect it - I opened up the back of the furnace body that I moved yesterday and then remembered - as I had two bodies I had a system of quick disconnect couplers, with copper braid jumpering them so that the QD surfaces didn't carry the current. But my short hoses don't have the QDs fitted.

Options -

A/ lug the long pipes over - I think they have the QDs
B/ remove the QDs from the furnace (actually not easy due to the construction around them
C/ use the replacement coil set that I have suitably suspended to avoid human contact (nasty high voltages)

I'm tending to option C/ at the moment but will think it over, meanwhile I've realised that I don't have a spare cable mounted 125 A socket to power the beast up, so I need to rob one from somewhere else.

Time for a cup of tea !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 08, 2020, 11:07:46 AM
I take it that you don't have a Rivnut set? It would be a 5 minute job to drill the old nut out and replace.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 11:35:03 AM
I do, and it isn't, as it rotates in the hole !

(The nutsert has pushed through the panel, but the bolt is firmly stuck in it so bolt would need sawing off in situ )

These 5 minute jobs - had one of those this morning . . . .  :bugeye:

It can bally well make do with three screws until the fate of the big blue box is decided !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 08, 2020, 12:32:16 PM
Steady on, it's not like you to get tetchy  :lol: :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 12:54:07 PM
Sorry Graham if I seemed to bite your head off - it wasn't intended.   :bow: :bow:

. . . but it has been a frustrating day not achieving anything like as much as I'd hoped
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 08, 2020, 02:55:31 PM
The plot thickens !

It seems that the spare furnace coil has one set of threaded connections and one set of clipped connections, so not easy for the pinging test  :(

Digging out the ends of the long pipes (ends were wrapped in plastic woven ex army sand bags) they do indeed still have the Quick Disconnect fittings, so it looks like a bit of pipe extraction is called for tomorrow and I'll hope to get them connected.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 09, 2020, 07:37:21 AM
So I woke up this morning with a bright idea ! Take the QD fittings off the long hoses, fit them to the short ones, and you don't have to struggle manipulating long heavy hoses  :thumbup:

Well the best laid plans of men and mice . . . . turns out that the short hose have a cone fitting and the long ones a face fitting . . .ah well it was a good idea while it lasted !

So I dragged the long hoses out from the tractor shed, tried to empty as much water from them as possible then, like fighting an anaconda, got them into a wheel barrow for their journey to the foundry.

While the QD couplings were off the hoses I gave them a bit of a clean up while passing my buffing spindle with the new bearings - well you have to don't you  :clap:

Then it was a case of identifying what went where. The Driver end was easy enough  as the terminal plate was marked, and I'd obviously labelled the pipes with a Sharpie before removal all those years ago, but only one mark had survived. Far end of pipe labelled to correspond and I started dismantling the terminal box on the  Inverting Furnace Body.

I'd forgotten that my solution to a non-conductive, non-magnetic strong frame was to make a sort of 'Fish Tank Frame' from epoxy fibreglass - I'm quite impressed with my effort - I even have thread inserts  to retain the panels. These were asbestos cement when I got the body, but I replaced them with cement 'tile backing board' - it's a bit friable and if this project continues I'll give them a coat of Sodium Silicate solution to firm them up a bit.

Getting the QDs onto their respective fittings was really quite a struggle - those pipe fight back at every opportunity. One of the QDs shows evidence of the retaining (stainless) ball bearings having at one time carried some of the current. That's what that huge copper strap and 70 mm cross sectional  jumper is for as it shorts across the QD - IIRC it was a retrospective mod when I had the problem before. But those fretted balls made locating the fitting quite a problem. It's OK for the ping test but if I get as far as pumping water through this beast they will have to be replaced.

So - drives cables / pipes (whatever you want to call them) are now connected and I need to work out how to safely feed the big blue box with a bit of 415 volt three phase for the ping test.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on April 09, 2020, 09:58:07 AM
Andrew, that really seems to be a beast waiting to be taimed. One thing is for sure, it makes very interesting reading about your struggles trying to tame it.
John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 09, 2020, 10:21:12 AM
John, at the moment I think the beast is winning !

This afternoon I wired a temporary 16 amp 415 volt three phase feed into the machine to try and run up the electronics and 'ping' the coil in the crucible to establish resonant frequency.

It starts the initialisation process then comes up with an error saying DEF - obviously more investigation required !


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 09, 2020, 10:54:57 AM
Well it seems no amount of button pressing is going to fix it anytime soon.... :lol:

So that Green button should latch something? Or it is and the latch is dropping out?

Is the DEF error a shortened version of some French word as most of the wording on the panel looks French?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 09, 2020, 11:12:30 AM
I reckon that seeing as the chiller is broke it means defrost  :) :) :) :)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 09, 2020, 12:46:48 PM
One issue I have sorted - I found a picture of when I pinged the coil back in 2006 and the L1 L2 L3  phase sequence indicator on the front panel is illuminated and the system says Pret (ready). So I have reversed two phases and now the indicator is illuminated  :thumbup:

Unfortunately the system still says DEF which I suspect refers to Default values, so maybe it's lost a few parameters (which will be a nightmare to re-create!) however it's back up battery is still showing a steady 3.7 volts

The "electronique" indicator is not showing, but is on my picture from 2006 but I can find no reference in any of the documentation to say what it means. Note that the "micro" indicator IS illuminated which I take to mean that the microprocessor is running.

Note that the "electronique" indicator IS NOT illuminated during initialisation in the 2006 picture.

Note: Pictures below are from 2006
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on April 09, 2020, 01:54:39 PM
Défaut = fault. Par défault mean default!

Have you got any of the French docs?


Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 09, 2020, 02:08:48 PM
Yes Matthew I have a manual which includes diagrams of all the power electronics but NOT the main microprocessor board sadly. The text descriptions are fairly sketchy as these things often are, but I had thought I might photograph a few pages and pop the over to you to peruse if I may.

Or I may run it through scanner and turn it into a .pdf - might make it easier - I'll kick a few things about tomorrow.

 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on April 09, 2020, 04:35:24 PM
Yes Matthew I have a manual which includes diagrams of all the power electronics but NOT the main microprocessor board sadly. The text descriptions are fairly sketchy as these things often are, but I had thought I might photograph a few pages and pop the over to you to peruse if I may.

Or I may run it through scanner and turn it into a .pdf - might make it easier - I'll kick a few things about tomorrow.

Great, could you include a photo of the manufacturer's plate in the pdf?

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 10, 2020, 09:57:59 AM
Well a day of two halves with greatly differing results !

I spent the morning scanning the manual into 'searchable pdf' format to send to Matthew - I have two versions - one came with the machine but is mainly schematics of the power electronics, and a second that CFEI sent me back in 2005 that has the same drawings but also quite a bit of text that looks to be mainly 'over view' type details in French. I started on the original manual as it is only 20 pages - when I opened the scan as a PDF it is NOT searchable - and I've tried all sorts of options in the Plustek application - total of 4 scans so far and still not searchable  :bang:

So I set too thinking and closely examining those pictures from 2005 and what was happening today. Does a red indicator ON mean a fault - or does it go OFF for a fault. Should that 'phase sequence error light' be on or off  :scratch: :scratch:

Well studying the circuits that I was scanning showed me that the two red lights indicating faulty 'Temperature' and faulty 'Ext 1' corresponded to two lines on page 10 feeding 24 volts to inputs on the main logic board. The temperature line was a series of  'normally closed' temperature sensors and interestingly that bit of the circuit has pencilled alterations as well. The 'Ext 1' one was apparently a simple link.

So out with the meter, and both those inputs are NOT at 24 volts - presumably an error 'up the chain' somewhere.  Make up short temporary links, put my fingers in my ears and :

WE CAN PING

Obviously I need to chase the faults 'up the chain' and see what's causing it, but certainly the microprocessor board seems to be OK and the power electronics must be reasonably healthy to kick the furnace coil into oscillation  :clap:

(It didn't help that the circuit diagram has '0 volts' and '24 volts' incorrectly drawn in each others connector block ! )
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 10, 2020, 10:04:34 AM
Great to see you making progress .. :zap:

Looking forward to the next instalment..... :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 10, 2020, 10:13:22 AM
My phone has an 'image to OCR' function Andrew if you want to send me the PDF I'll attempt to make it searchable for text.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 10, 2020, 10:19:23 AM
Thanks Pete but I've not given up with it yet - I have other bits of software to unleash on it still !

So - what happens if I put a bit of steel in the crucible and 'ping' it again? Theoretically the frequency should be lowered - but is it ?


. . . . YES  :clap: :clap:

(This just confirms that it IS actually measuring the frequency and not just throwing up random numbers !)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 10, 2020, 11:25:13 AM
Fantastic news Andrew. In my book when a fault lamp is illuminated it indicates a fault. Have you determined what the three sensors do? (I see that originally it was two, but they've been scratched out and a third drawn in)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 10, 2020, 11:44:56 AM
Graham, yes I agree on for fault, but the picture of it 'ready' back in 2006 had the phase rotation light 'on' - in fact I have proved today that it has to be 'off' in fact so not sure what was going on then ! (*)

The various sensors all seem to be thermostatic one on things like the water source, internal big coil, the tuning capacitors etc.

The simple link in the other chain is something to do with the key switch that switches between the ping mode and normal heating.

More investigation needed tomorrow - at the moment I'm mentally exhausted  :bugeye:

(*  Later Edit :No it doesn't - only the first picture from 2005 while it is initialising shows the phase rotation fault indicator 'on' . I must have swapped phases for the other pictures !)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 10, 2020, 02:20:47 PM
Excellent news Andrew, I have complete faith in you! On the chiller, lots of food industry factories use brine tanks for fast freezing, also ice cream and chilled desert makers, have you any contacts within aforesaid industry that might be able to link you to a chiller unit! You have probably already considered this, but just in case......Good luck! I can smell hot metal even this far north!
Phil
East Yorkshire
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 10, 2020, 03:29:33 PM
Thanks for the thoughts and suggestions Phil,

Matthew - I have emailed you the searchable .PDF scan of the manual and also a picture of the machine plate as you suggested. The file is pretty big at 8 Mb so I hope that your eMail server doesn't bounce it.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 11, 2020, 05:37:59 AM
So this first of the 'fault indications' that I linked out yesterday is solved  :thumbup:

Taking my handy Telecoms cable tracer to the job I followed the wiring to where, according to the circuit diagram, there is a simple link between the 'Saphyr Monocrate' digital input, and 24 volts. No! The cable wanders all over the place ending up on an undocumented 110 volt contactor where this 'link' is the one and only used contact. But what drives the contactor?

Again using the cable tracer lead me a merry dance ending up on a  3 core cable Ty-Wrapped to hoses deep in the back of the one panel that doesn't open :bang: Poking a camera in showed some sort of junction again Ty-Wrapped to the underside of the hose with a black cable emerging next to the hose to / from the water flow gauges. Ah - the penny dropped - the flow gauges are not just visual, they have a magnetic float that operates a reed switch THAT OPERATES THE CONTACTOR  :clap:

Some rare earth magnets and masking tape simulated water flow, and sure enough that's one "fault" knocked on the head  :thumbup: I must have been through this process all those years ago I suppose, but it's lost in the mists of time.

A quick cup of coffee and on the the next fault chain - the temperature sensors.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on April 11, 2020, 06:14:01 AM
So this first of the 'fault indications' that I linked out yesterday is solved  :thumbup:


Some rare earth magnets and masking tape simulated water flow, and sure enough that's one "fault" knocked on the head  :thumbup: I must have been through this process all those years ago I suppose, but it's lost in the mists of time.



I love a bit of fault finding, keeps the old grey matter working.... :zap:

So I hope you are going to document all your findings this time... :coffee:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 11, 2020, 07:35:47 AM
Well John this is all VERY odd !

I've spent quite some time cable tracing - some of the temperature switches are literally impossible to get at, they must have been fitted before the machine sub-assemblies were joined, and others required quite a bit of contortion to get at.

BUT I found a switch on the water inlet manifold that was open circuit and accounting for that  series line of about five switches not being pulled to +24 volts hence the error. I pulled the wires off the switch and linked them proving the 'fault'

However, when I finally got a spanner onto the flats of the switch and got it out, it turns out to be a pressure switch monitoring the inlet water. So hiow the heck all those years ago did I manage to 'Ping' this beast with no water source and certainly no pressure on that switch - VERY ODD.

Anyway at least I've found what's doing it - now I need to decide how to proceed. :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 11, 2020, 10:18:46 AM
So having tested that it works, I returned the water pressure switch to it's place on the water inlet manifold, but left a very obvious jumper link across it to prevent me forgetting I'd done it.

This afternoon I dug out the hoses that used to run between the (now defunct) Water Chiller and the Furnace Driver - you may remember, when I first got them from their rotten storage pallet they had been eaten by rats. Well it turns out that the damage was confined to one pipe only, fortunately the longer one (previous location had dictated unequal pipes) and less than 24 inches from the end. I was able to re-terminate that hose with the existing fittings and make two equal length hoses. Tough to press in those barb fittings, but much aided by Lambing Birthing Gel - basically agricultural KY Jelly  :clap:

So if I ever get another water chiller at least I have a starting point for the hoses.

Hence now the hunt is on - I need a water chiller that will provide water thus:

 - 25 litres /minute

-  3 bar minimum pressure

-  5 bar maximum pressure

-  40 deg C Maximum temperature

-  5  deg C Minimum temperature

The previous one consumed about 11 kW and provided 39 kW of cooling - I always felt that that amount of cooling was barely sufficient however I had interposed a second heat exchanger in the form of a domestic central heating system copper hot tank as a sort of negative thermal store, but I now suspect that the actual problem may have been thermal transfer (or lack of it!) between the main tank and it's internal coil.

So those of you who scan commercial on line auctions can you please give me a 'heads up' if you see any big chillers listed.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 12, 2020, 09:10:57 AM
Happy Easter everyone.

At a bit of an impasse until I can sort out the cooling so I've turned my attention to sorting out the foundry itself.

This morning I have removed EVERYTHING not directly foundry related, (and some that are!) to generate floor space, and have moved all the equipment up to one end of the building. I was even able to open the small pedestrian Roller Shutter Door for the first time in years - if you look through it, the round plastic water cistern is what I used to use as a duct sitting upside down on the Water Chiller with a large rectangular hole in it's side holding galvanised duct to the outside world. And inside it I'm glad to say I've found the safety cover that keeps fingers off the Driver output terminals.

This has allowed me to sweep half the concrete floor, vacuum it with the workshop vac and give it a coat of Sodium Silicate to hopefully seal it a bit and stop the dust rising. Google gives me contradictory advice regarding dilution ratio, but I used 1 part very syrupy heavy Sodium Silicate  to three parts water. That half of floor so far has used 2 litres of concentrated Sodium Silicate.

Will it work - well again there's contradictory advice 'out there' - so long as it dries it's can't hurt at least  :scratch:

. . . so now off to plot and scheme cooling methods - joules / kilowatts / degrees Centigrade and all that stuff !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 12, 2020, 11:23:52 AM
So cheating a bit and using an On Line water heating calculator it turns out that in theory, a water filled 1000 litre  IBC would last for 44 minutes if pumped round the furnace and furnace body (which would be dumping about 40 kW into it) before reaching the upper temperature limit.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 12, 2020, 11:37:52 AM
Now ideally the IBC would have a copper coil immersed in it, being cooled by the bulk of the water, which would be constantly be being replaced thus extending the operating period to continuous.

So I need a source of water - OK I have a stream but it's about 75 metres away - not impossible to pump but a pain. Returning the used water to the stream is less of an issue as the surface drains run there.

BUT

Since we've been here we've been unable to explain a 'mystery 24" manhole cover' at the back of my workshop and not far from the foundry. We've never been able to open it - it looks perhaps to have been welded shut, but not actually expended much effort on it - but perhaps now is the time because . . . .

Searching the on line bore hole database shows a borehole in approximately the same place, and details of the borehole are available on line - all nine pages of data !

http://scans.bgs.ac.uk/sobi_scans/boreholes/651959/images/12563414.html

Now if this IS the borehole, and if I can lift the cover, and if it's not been back filled there is a possibility of free water fairly close to where I need it . . . mmmmm . . . . thinks . . .

. . . any volunteers to open a darn heavy sealed man hole cover ???
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Joules on April 12, 2020, 12:47:23 PM
Drill it tap it, fit a spark plug...   Now add 50’ of chain secured to cover and staked out opposite from workshop.  Once the cover has blown, you just need to follow the chain and dig out the cover....   Simples...

 :thumbup: :jaw:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: chipenter on April 12, 2020, 02:24:29 PM
We used to lift those with a tractor hydraulics , slide the pulling bar though the two keys and lift until the front wheels are off the ground , then bash round the perimeter with a 5 pound hammer , the vibration did it every time .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 12, 2020, 02:56:26 PM
A big lever key should pop that open. Might want to run a jetwash around the lip first.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on April 12, 2020, 05:54:03 PM
Why not drill a small hole in the lid and pass a borescope / plumb line through to have a look before going through the effort of opening it. It might have been filled up or gotten blocked up with debris.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on April 12, 2020, 07:37:36 PM
24" is a heck of a bore hole!!!

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 02:37:14 AM
Why not drill a small hole in the lid and pass a borescope / plumb line through to have a look before going through the effort of opening it. It might have been filled up or gotten blocked up with debris.

That’s a good idea
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 02:40:22 AM
24" is a heck of a bore hole!!!

Sent from my SM-G892A using Tapatalk

The November 1939 document actually says diameter at top 5 foot 9 inches  :bugeye:

But it’s the manhole that’s 24 inches !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 05:27:40 AM
Glad to say that the first half of the floor had mainly dried over night with the exception of a bit by the wall where I was probably a bit enthusiastic with the sodium silicate solution.

It has made a very noticeable difference to the previously rather dusty surface - you can draw a hand over it and no dust comes off at all :thumbup:

So it was a case of 'rinse and repeat' this morning - moving everything to the now sealed end using the pallet truck, vigorous sweeping and vacuuming and another session mopping 3:1 water / sodium silicate solution to the newly exposed floor. The wind has got up and this lot was drying much faster as I have doors both ends.

It's my intention to give it a coat of grey industrial floor paint when the seal is thoroughly dry, and although I have the paint I don't have sufficient white spirit to dilute the first coat, and I only have one 12" floor roller. In these Covid-19 isolated days it's not just a case of popping out to get them so I've orders in place - at least it'll give the seal longer to dry (sell the positive !)

Stay safe everyone.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 10:43:29 AM
Waiting for concrete sealant to dry is rather like waiting for paint to dry - boring  :clap:

So I had another go at the manhole cover. I'd intended to pressure wash the joints as suggested by Pete. but my brand new portable petrol washer that's only run for one day refused to start - no spark  :bang: And it's far too much of a fag to dig the big steam cleaner out from the Tractor Shed as it's buried again at the back.

So I went round the joint between the frame the the cover with a small cold chisel clearing as much rust as I could, then giving it a good talking too with a sledge hammer -  I assume it's malleable iron not just ordinary cast iron !  Still no movement so I've started a program of squirting Plus-Gas into the crack - it is soaking in so may do some good. When I've done that for a day or two I'll gently vibrate it with my Kango concrete breaker.

At the moment I'm loath to drill holes in it as undoubtedly there will be strengthening webs in it underneath that I don't want to hit, and the light on my endoscope camera is not too bright.

Re-reading the borehole survey report there are a few contradictions and I think, looking at page 6 it may be referring to 6 bores made in the period 1922 to 1962.There is also a reference to 'Back Filled it to 90 Down' however there is also a reference to 'Filled in Information from visit 16/10/62' - so who knows - certainly not me :scratch:

Anyone know how I can print a copy of the 9 pages of that report ?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 11:16:11 AM
This looks to be the same specification so I better be careful!



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 13, 2020, 12:38:46 PM
Bit more fragile than the 60-tonners outside out site :D

What I would do is measure the hole diameter in the key slots. Get a bolt about 150mm long with a shank that fits closely in the hole and cut the sides off the head so it can drop in and turn through 90 deg. Get a piece of box section steel maybe 6 foot long and drill it over-sized for the bolt to allow a bit of wiggle. Measure the distance from the key slot to the edge frame and weld a chunk of flat bar on the box section such that the bar acts as a fulcrum bearing on the frame. Now pop the box section over the bolt and run a nut down it, and start bouncing on the far end to lever the cover up.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 13, 2020, 03:03:24 PM
You could save each page as an image and then print it to PDF (at least, in windows)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 13, 2020, 03:41:16 PM
I can only get about half a page to a screen for some reason  :bang:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mc on April 13, 2020, 06:19:02 PM
Page 9 is apparently too big for the viewer?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mc on April 13, 2020, 06:23:56 PM
And what you really want is a manhole lifter.

Utility engineers who deal with underground pipes/cables should have them in their vehicles.
You really want an Openreach cabling engineer though, as they carry hydraulic lifters.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 14, 2020, 04:50:58 AM
Cut a new one from steel plate, using your plasma cutter table... then have at the old one with the biggest hammer you own  :) :med:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 14, 2020, 05:05:28 AM
Wow Morray how did you do that ? Thank you so much - all the various browsers that I tried would only open half a page at a time.

Yes a hydraulic lifter probably is the way unless I take the Ade approach, which I must say I have considered !

This morning I welded up a simple slide hammer from some re-bar and a bit of 8 mm plate - it's not strong enough, as you can see in the picture the Tee bar is bending. Ideally I'd use Pete.s approach with an HT bolt with the head cut down, but I don't have any 1" HT bolts in stock so I used what's to hand.

I will try again with something a bit stronger, but by golly this lid is well and truly stuck !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 14, 2020, 05:34:52 AM
I followed up on the Slide Hammer with a bit of controlled violence from a Kango concrete breaker, the idea being to vibrate and hopefully crack, the rust bond between the cover and it's frame.

The Plus-Gas IS penetrating into the lid/frame gap most of the way round but it's still not anything like free.

I suppose in extremis I could try breaking the concrete round the frame, and digging out the complete frame with lid, an then leave it soaking in Citric Acid for a few weeks  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: djc on April 14, 2020, 04:00:31 PM
What I would do is measure the hole diameter in the key slots. Get a bolt about 150mm long with a shank that fits closely in the hole and cut the sides off the head so it can drop in and turn through 90 deg. Get a piece of box section steel maybe 6 foot long and drill it over-sized for the bolt to allow a bit of wiggle. Measure the distance from the key slot to the edge frame and weld a chunk of flat bar on the box section such that the bar acts as a fulcrum bearing on the frame. Now pop the box section over the bolt and run a nut down it, and start bouncing on the far end to lever the cover up.

All of the above except the last sentence. Weld two chunks of bar to it so they bear on the projections of the frame on both sides and then use the nuts on the bolts to wind up the cover like a giant bearing puller. Once the bolts are in the cover slots strut them apart with a piece of timber.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Will_D on April 14, 2020, 04:56:50 PM
Are there any visible signs of weldinding? Or is it just rusted in tights?

Welds should be easily visible!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 14, 2020, 05:08:48 PM
I'd initially thought that it had been welded, but my various attempts over the last few days to open it have now convinced me it is a combination of tight packed clay and rust .

I suspect these covers fit in a taper fashion - I've been working away at the junction but it's pretty solid. I'd hoped that the Kango treatment would at least have broken the bond, but apparently not.

My fear is that a trimmed bolt head in the slots may end up just pulling some the the cover round the slots out as it'll be exerting far more force than intended. Hence still scratching away at what gap there is.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 14, 2020, 05:23:51 PM
I have seen covers with burst key holes before Andrew. Usually on private property because a utility would get them changed.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vintageandclassicrepairs on April 14, 2020, 06:08:07 PM
Hi Andrew,
What about making a fire sat on the lid? the heat would expand the cover more so than the frame
It might be enough to break the joint free

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 02:46:12 AM
Pete yes that’s my fear !

John, I’d not thought of fire as it’s a bit close to the goose fence , but I had considered my Karcher MPDS battlefield decontamination unit, as it’s a steam cleaner on steroids but it’s rather deeply buried at the back of the shed.

As I’ve solved the not starting issue with my small Chinese pressure washer (*) I’ll have a go with it this morning. After all it was a sensible suggestion from Pete some time ago to try and flush out the gap with a pressure washer.


(* why would it not start? Oil sensor switch saying low oil when dip stick says full! Importers suggestion: fill the oil until it runs out of the dip stick hole! I think they’ve had this issue before. It’s a copy of a Honda engine mounted in a wheeled frame and I suspect that it sits rather more tilted than the engine designer intended)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 04:48:45 AM
So with the finest (so highest pressure) nozzle fitted I gave the manhole cover an intensive session with the pressure washer. It was obviously doing 'something' as every now and again a great spurt of brown rusty water would came back at me in the face !

I blasted it vigorously for quite some time, then gave it more violence from the sledge hammer before again an intensive session with the pressure washer. Not easy to see what it's done with all the water about so I blew it off with an air gun.

As you can see from the pictures below the 'gap' is much more pronounced in some places but still totally jammed full in others - it MUST have helped I tell myself  :clap:
 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 15, 2020, 05:13:04 AM
How about another approach, Andrew? If you have plasticine or similar, plug the elongated holes around the edge, build a dam around the periphery and flood the whole area with a concentrated solution of vinegar/citric acid/phosphoric acid and put a lid on it to prevent evaporation?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 05:53:18 AM
Another good suggestion Graham that I will put on the list to try.

I have a recently retired and recently divorced Fireman who got stuck in isolation on the farm in his caravan by the virus when his arranged site closed and he'd already left his other half. This morning he's seen what I'm doing (from the prescribed 2 metres!) and is taking it as a personal challenge that he cannot open it.

Who am I to deny him his entertainment - it has to be better than just polishing his caravan, he'll have no paint left  :clap:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 15, 2020, 07:56:31 AM
it has to be better than just polishing his caravan

Hmm, I've never heard it called that before!  :lol: :coffee:

Can you get a pry bar into the slots at the edge? Maybe you could see some movement?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 08:13:20 AM
I've been swinging my not inconsiderable mass on the end of a 6 foot pry bar this morning, and no movement what so ever!

This afternoons job is to make a slightly more substantial slide hammer !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 15, 2020, 08:19:04 AM
This may sound daft, but have you tried putting a couple of manhole keys in the slots, then putting a bar between them and trying to turn the manhole lid inside the frame, it occurs to me that those two prying slots could also be the holes for a couple of tabs to come out if the manhole cover is a bayonet type fitting, and locks down to the frame.
  I like the fire idea, but then, anything to do with fires.......... my late aunt used to say "the smell of smoke follows naughty boys"
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 11:01:58 AM
Phil, There is a location tab that stops it rotating and ensures correct alignment.

But never mind:

We Have A Borehole

I made up my more substantial slide hammer, and even using it like a maniac for quite some time had no effect. In places I could get a hacksaw blade into the gap the full two inches of cover thickness, but elsewhere it would not go in at all - managed to clear a bit of debris using it but nothing substantial.

So I decided to use the slide hammer as an attachment and do a tentative lift with the Fork Lift to put tension on the cover - no lid movement what so ever, and continuing the entire massive concrete structure started lifting  :bugeye:

Clearing the turf away from round it, (to stop it falling into my nice water source!) I carried on lifting until a gap appeared showing WATER - lots of water !

Getting my cable drawing fibreglass duct rod, I tried pushing it down - there was a definite circular 'thing' in the centre under water - presumably a pipe, and I was able to push at least 20 maybe 25 metres down the hole before feeling any resistance. All this was at an odd angle as the concrete structure was balancing on one key (my slide hammer) off the fork lift.

Common sense told me to lower it back before there were any accidents  :clap:

So now I need to work out what's next  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 15, 2020, 12:52:45 PM
What a result  :beer:

Things are definitely looking good for the future of this project  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 15, 2020, 01:41:56 PM
that manhole cover is REALLY stuck, but no matter, you have a supply of cool water! onward!!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 15, 2020, 02:50:15 PM
Thanks for the encouragement chaps . . . .

. . . .  you do know that it's DANGEROUS to encourage me don't you  :zap:


So who knows about the maths of heat exchangers? It would be nice to pump cold water from the borehole though a simple heat exchanger the other side of which carries the 'furnace water' that needs 40 kW removing

... lot of variables (too many!) - no idea of which / what heat exchanger - make one / buy one / beg one / steal one
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: charadam on April 15, 2020, 07:34:20 PM
Hey! I was in the shower when you took the lid off!

Most unpleasant experience and my solicitors will be in touch.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: chipenter on April 16, 2020, 03:17:47 AM
Standard domestic indirect hot water cylinder , with the coil to furnace and cold circulating in the tank will shift a lot of heat .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 16, 2020, 04:48:01 AM
SO.... drill hole in manhole cover - lower pipe, job's a good 'un!  :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 16, 2020, 07:30:43 AM
Standard domestic indirect hot water cylinder , with the coil to furnace and cold circulating in the tank will shift a lot of heat .

I used that system as a 'cold store' at my last place but got the impression that actually it was limiting the cooling due to the relatively low heat transfer - may be the tank I used was furred up !

I'm now looking at 'welded plate' stainless heat exchangers - they are remarkably compact for their capacity - the bit I'm not too sure of is their effectiveness at the  temperatures involved. My 'bore water' will be nice and cold out of the ground - probably 14 C max. My circulating water round the furnace and furnace driver electronics I want to keep to less than 30 C - so the differential of 15/16 degrees is not what for instance you would get with a domestic set up.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 16, 2020, 07:40:25 AM
SO.... drill hole in manhole cover - lower pipe, job's a good 'un!  :beer:

Yes Ade, that's the idea, but I'd still like to be able to remove the man hole cover.

I've been tapping a 3" long strip of 1.2 mm  steel 15 mm wide gently into the gap - if you start where the gap is full depth (2") and work against the 'wall' of the next bit you can crumble bits of the rust / clay / mud until eventually you get another full depth bit, but by heck it's as tedious job. If only the Grand Children could come and stay - ideal pocket  money earner except for our current virus lock down !

Drilling the cover will be a last resort - most bore hole pumps seem to be 3" diameter - also I have absolutely no idea if the  lining pipe is in the centre of the circular lid, or well to one side, and it would be a shame to miss.

Remember that the underside of these covers are webbed like the under side of a surface plate so random holes can end up in unfortunate places un-knowingly  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 16, 2020, 11:39:07 AM
Matthew (who lives in France) kindly got in touch with CFEI on my behalf to find out about back up batteries and what they retain. Not really unexpectedly they have little information to reveal other than 'change the battery with power on' which is the same for most systems.

The lithium battery in 'half AA' size 3.6 volts is fortunately a standard RS item so one should be delivered tomorrow, plague, tempests and viruses permitting.

Thank you Matthew for that.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: David Jupp on April 16, 2020, 12:48:20 PM
Plate heat exchangers are good - but for welded ones make sure the water is clean and soft, as you can't get them apart to clean.

The fluid velocity is important to get the heat transfer coefficient up. A single coil in tank won't be great, as the velocity around the coil will be modest at best.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 16, 2020, 01:24:56 PM
Good point about not being able to dismantle for cleaning. Would plumbing arranged for an occasional reverse flush be sensible?

The water circulating in the furnace / furnace driver loop can be closely controlled as it is always the same. This cannot be said of water from the bore hole. Historically bore holes round here ceased to be used for public supply due to high iron content. Not sure how much filtering and settling it is practical to apply.


Assembled gasketed bolted together plate heat exchangers are far less available than brazed / welded ones.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: David Jupp on April 17, 2020, 03:40:28 AM
Not convinced that reverse flush will help much - deposits tend to be uniformly across the plates.  On a plant where I worked, we used to swap plate exchangers over weekly, strip and wash down the plates with a 'steam gun'.  That was though in a location where we needed particularly good cooling, and part of the system was open to atmosphere so 'bugs' could get in - other exchangers were cleaned far less frequently.  Welded plate exchangers are found in most combi boilers and seem to last quite well...

Spiral plate exchangers can have a door on the end for cleaning, but I bet they cost more.  Shell & tube likely to be quite good, though larger.  I guess a lot will depend on what you can find and price.

A simple pipe in pipe exchanger is good if you don't need  lot of cooling - or they tend to get large and unwieldy.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 17, 2020, 03:51:47 AM
How about  having a side tank with pump, which is valved off from the cooling circuit until required,  and filled with something nice such as concentrated phosphoric acid? Heat it, too, and it'll shift any residue very effectively.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 03:56:12 AM
I may be doing a re-think here !

The original chiller cost about £2 per hour in electricity to run

I am being charged about  £1.80 per cubic metre of treated drinking water. So if I can get adequate cooing in the heat exchanger using my tap water realistically it's no more expensive than using the original (and now) defunct chiller. It will eliminate the need for expensive bore hole pumps, trenching etc.

This would mean that the heat exchanger cold side would have filtered treated water of course.

So this morning I need to measure how fast my local internal water distribution system can deliver water to the foundry, then somehow work out if that is an adequate source of cooling for the heat exchanger  :scratch:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on April 17, 2020, 04:37:01 AM
If only you had a hydrant somewhere  :scratch:    :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 04:42:12 AM
And the answer is 3 gallons in 55 seconds at 10 degrees C

Or 14.8 litres / minute.

But how the heck does 14.8 litre / min at 10 degrees C through a heat exchanger translate into energy extracted from the primary?

There must be some sort of 'transfer function' for the H.E. that varies with the temperature differential, and the cooling water is going to be raised in temperature by a certain amount. And that volume of warmed water in (say) an hour translates into a certain amount of energy but now I'm getting on very shaky ground.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 04:43:02 AM
If only you had a hydrant somewhere  :scratch:    :thumbup:

It's a long way away and that would be naughty !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: David Jupp on April 17, 2020, 04:53:39 AM
You need to work out the overall heat transfer co-efficient for the heat exchanger - I did some basic Chemical Engineering on a course years back.  All the equations are probably available on-line...  but not sure you'll have all the data.

It's a bit of a 'chicken and egg' situation though as the OHTC is influenced by flow rates in both circuits, any fouling, boundary layers, etc.  The exchanger manufacturer should be able to provide some guidance.

First thing is do you know the heat load to be dealt with? 

You're going to end up with quite a few estimated values - and of course the water flows will change when you connect things together.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 06:27:27 AM
David,

I need to remove an estimated 40 kW of heat from the primary circuit. The primary circuit is water (with a bit of glycol) that will be pump circulated at approx  25 litres / minute. I don't want the primary to go above 30 Centigrade. The secondary will be fed with water at (say) 10-15 degrees C at 14 litres / minute.

But the unknown of course is the heat exchanger and it's characteristics as I 'ain't got one yet !

I have a feeling that to err on the large size is sensible, and throttle the secondary cooling water if need be - if indeed 14 litre / min at 15 Degrees is sufficient  :scratch:

I suppose if one assumed 100% H.E. efficiency and the cooling water rising from 15 to 30 degrees at the 14 litre / min rate how much energy does that take?

Now I found this 'handy rule' on the web:

Handy rule: multiply the hot water flow rate in litres/minute by the temperature rise in celsius. Divide by 100 and multiply by 7 to get the boiler DHW output in kW. Example: 12 litre/min at 40C rise: 12 x 40 = 480.
 


Applying that says that it takes 14.7 kW to raise a flow of 14 litre / min by 15 degrees C so I am out by quite a margin from my requirement  :bang:

I need three times that amount of cooling so presumably three times the water flow rate which is a problem  :(
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: David Jupp on April 17, 2020, 06:57:50 AM
40kW = 40 kJ/sec

14 ltr / minute = (roughly) 0.25 ltr/sec.  or 0.25 kg/sec assuming water s.g. = 1

A 15 C temperature rise for that = 0.25kg x 15 C x 4.2 kJ/kg/C = 15.75kJ

So yes, quite a bit out.  You can assume more or less 100% efficiency of heat transfer - the heat transfer calculations relate to how big the exchanger needs to be and how fast the water has to flow in the internals.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 17, 2020, 07:12:19 AM
So, how much water can you get out of the bore... And how cold is it..

This is a bit like the penultimate sub-plot of 'Trustee from the Tool Room' where Keith discovers a discrepancy in the hydraulic cooling calculations for a saw mill and earns himself a tidy little commission...


-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 07:34:58 AM
It's certainly a bit of a roller coaster isn't it !

Cheap bore hole pumps on eBay claim a figure of 2000 - 3000 litres / hour plus so are in the ball park, but whether the bore hole can sustain that sort of draw, and whether the pumps can deliver it from the depth of the hole are more variables!

. . . argh . . why is life never simple . . . 


 :coffee: :coffee: :coffee: :coffee: :coffee: :coffee: :coffee:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 09:52:29 AM
Well according to those records I found, this bore hole was able to produce 150,000 gallons a day  in 1947  :bugeye:

But IS it the same bore hole - I strongly suspect so, as if I put the grid reference on the bore hole survey  (TQ 7782 1741 ) into a 'grid reference locator' on the web that uses Google Maps it shows me a point about 15 yards away from where it actually is, which I suspect is within the margin you'd expect a reference to be accurate to in the circumstances.

So: Still need to gain safe access to the bore - possibilities:

A/ Smash the cover and replace - probably not too easy it's pretty solid - sledge hammers bounce off !

B/ Chip away flaunching cement round manhole surround - pull the lot off - leave in citric acid for a few months and re-cement with modifications

C/  Lift off entire upper works as previously partially done and re-build with new incorporating control chamber above ground

B/ Is probably favourite, and C/ is potentially dangerous so when the rain stops I'll tentatively attack the flaunching and see how tough it is.


(Typically as these things go, as I was typing this I got a phone call response to my plea for a water chiller from a fellow who has an 8.5 kW unit - I assume that is 8.5 kW electrical consumption - 30 kW chilling - so right order of magnitude but sadly the price isn't the right order of magnitude!)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 17, 2020, 10:10:10 AM
The rain has stopped so I ventured out to have a poke at the cement flaunching round the man hole.

The good news is that it is not impossibly hard - actually it looks suspiciously as though there's quite a bit of soft sand in the mix (should be sharp sand) so perhaps with the Kango and a newly sharpened point I may make a bit of progress.

Need to clear all the turf and earth back first - I may well get started tomorrow, as I have half a foundry floor to paint and when that's done I can't work in there anyway until it's dried for the next coat !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: philf on April 17, 2020, 04:34:38 PM

But IS it the same bore hole - I strongly suspect so, as if I put the grid reference on the bore hole survey  (TQ 7782 1741 ) into a 'grid reference locator' on the web that uses Google Maps it shows me a point about 15 yards away from where it actually is, which I suspect is within the margin you'd expect a reference to be accurate to in the circumstances.


Andrew,

A 4 figure grid reference specifies the position to 10 metres. (10km, 1km, 100m, 10m).

15 yards I would have thought is close enough.

Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 18, 2020, 07:49:07 AM
I've been thinking about this and comparing it to the kit we use at work, a lot of which is water cooled.

Our most powerful concrete saw uses a 27kw motor, and the drive electronics and motor are both cooled by the (same) water feed, which is usually just fed from a 1/2" hose up to 25metres long off a domestic water supply. The motor is just a cooling jacket. Very often the supply is quite marginal and you can get away with surprisingly little flow without tripping the thermal protection.

Last year I ran three of these (http://www.galiot-kazan.narod.ru/galiot/supplys/hidroagregats/pdf/003.pdf) at full load for hour after hour some days. The coolant was by a single 110v submersible dropped in the Thames feeding a 3-branch manifold. I think that if your bore hole is deep enough you could simply drop a decent sized submersible in the top and set up a return hose with a weighted end to return the water back into the bore after doing a lap of the heat exchanger. The thermal store of the bore hole will be immense.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 18, 2020, 08:20:39 AM
Yes Pete, I've been thinking along similar lines :thumbup:

I've just worked out that a 1000 litre IBC starting at 15 deg C will take an estimated 27 minutes to get to my (self imposed) upper limit of 30 degrees C - so for a 90 minute 'session' I could even get away with 3 IBC's that have filled up gradually over the preceding days. And that time can be extended a bit if I had a tap filling them at the same time.

This is ASSUMING the heat put into the water IS about 40 kW - I have no ideas if that figure is correct - 39/40 kW was the cooling ability of the dead chiller which I thought at time was marginal, but looking at some of my notes from back in 2005 I was working on 17 kW - I can only suppose that lower figure came from the firm I bought the furnace from !

I've been trying to find other examples of similar sized induction furnaces to compare their water cooling, as I'm sure that they must all be much of a muchness, but so far I've drawn a blank.

Today I've cut all the turf and earth back from the manhole, as the builder who rents one of my containers has volunteered to chip the man hole cover surround out of the flaunching this coming Monday - I'd intended to do it myself but he's far better equipped to do it than I.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 18, 2020, 09:15:49 AM
At last, a useful reference to required cooling from:

https://www.tct-tesic.com/wp-content/themes/tct/assets/documents/induction-furnace-handbook.pdf

"Cooling water volume
is determined mainly by the electrical output. One can say roughly that approx.
27% of the furnace output and the heat losses from the crucible wall will have to
be dissipated. In rough terms, one can reckon on approx. 35% of the furnace output as the total loss performance that must be dissipated."


So for my 100 KW furnace  35 KW cooling, which is right on the money for my original 39 WK chiller  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 18, 2020, 10:59:15 AM
I've been thinking about this and comparing it to the kit we use at work, a lot of which is water cooled.

Our most powerful concrete saw uses a 27kw motor, and the drive electronics and motor are both cooled by the (same) water feed, which is usually just fed from a 1/2" hose up to 25metres long off a domestic water supply. The motor is just a cooling jacket. Very often the supply is quite marginal and you can get away with surprisingly little flow without tripping the thermal protection.



Presumably the motor being sizable will be fairly efficient? The cooling I assume only has to lose the energy lost by inefficiency so if it is 75% efficient it's only having to carry away 6.75 kW

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on April 19, 2020, 06:55:22 AM
Hi Andrew

You do have interesting problems don't you. :clap:

I've been thinking about this at odd moments.  Presumably the main argument against a total loss system is that it would scale up quickly and even a thin layer of scale would reduce heat transfer significantly.  Can the pipework be descaled with acid? I don't know if citric acid would dissolve scale - I expect it would.

I'm intrigued by the idea of using the stream.  That would give the possibility of a counter current heat exchanger  which would potentially be more efficient.  My usual interest in trying to do jobs for little or no expenditure is imagining a series of old domestic radiators lying in the stream. :scratch: :loco:

I'm sure there are design guides for heat exchangers, but without having consulted any :bugeye: I recall from physics lessons that heat transfer is proportional to wall thickness, surface area, temperature difference, etc and I wondered whether this might help in some ball park calculations. :smart:

I had in mind if you know the area extracting heat from the furnace and the temperature difference and you know the temperature difference you are aiming for in the cooling section then you can calculate the area needed - and similarly for different  materials.

I'm not sure whether to mention this, but even though the borehole is there already, do you need some sort of abstraction license?

That enough rambling thoughts for today. I look forward to seeing your progress.

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 19, 2020, 08:08:04 AM
Russell,

From what I've recently discovered about 'welded plate' heat exchangers they seem pretty efficient in terms of heat transfer so I don't think there is any need to use direct cooling, in that any cold water source can be isolated from the furnace plumbing by the heat exchanger. This is really needed anyway as the water needs to be low conductivity and with added glycol.

Although the stream sounds an attractive proposition, it's a long way from the foundry both for laying pipe and pumping the water, whereas the bore hole is only 15 yards away.

The bore hole water will undoubtedly be heavily laden with iron, as that's why it ceased being used for public supply, so my heat exchanger will presumably eventually clog up with it, but as Seadog said, it can be acid flushed, and frankly they are fairly cheap for what they are. (A 50 plate welded one rated at 90-100 kW is less than £100 from Poland or Czech including postage). I would err on the large size for the H.E. as I can easily throttle the cooling side if it proves excessive.

As far as I can tell an abstraction licence is only required if drawing more than 20 cu M per day which I wont be.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 20, 2020, 08:46:09 AM
Today I managed to open up the Bore Hole  :thumbup:

My friend Andy came with his big Kango clone and in a matter of 20 minutes freed the man hole cover frame from it's flaunching. Whoever did it originally used soft sand (should be sharp sand) so it came away remarkably easily having been given a seeing to with the breaker.

I slid the forks of the fork lift truck under the assembly and carried it away for dealing with at a later time - it's a blooming heavy lump of iron !

So this exposed a 24" pool of water - again I slid my fibreglass duct pulling rod down it and it went down to 174 foot  :bugeye:

I rigged up my petrol 2" water pump, with a foot valve and rigid pipe into the bore hole, and flat pipe out to a reasonably convenient 'rodding eye' on my roof and surface drain network that leads about 60 metres to the stream. Starting the pump water fairly gushed out down at stream level and the bore hole level started falling.

As the level went down, man steps were revealed set into the side of the bore hole - it's a brave man that goes down those  :bugeye:

It was my intention to carry on pumping until I got to the limit of the suction hose to see what was revealed, but at this point the engine died on the pump - would briefly start on choke but immediately dies. So pumping operations had to cease until I find the pump problem.

A quick tidy up and a temporary cover put over the hole was enough excitement for one day  :clap:

(Pete. will recognise the cover  :thumbup: )

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 20, 2020, 09:24:46 AM
The only living boy in New Cross eh? Is this a sign (see what I did there) of a misspent youth robbing sub stations and knocking off policemans helmets? I used to have one from Reading Rock festival (1978) that said "No glass in the arena please" It was a good fit on the floor of the transit van, and covered the ribs to give us a much more confortable, and warm area to sit on the way back! I think I eventually sliced it up for under bench shelving!
Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 20, 2020, 09:49:23 AM
There is more to this than meets the eye Andrew (at present anyway) 174 ft of draw wire, did you come to a stop, or was that the extent of the wire on the reel? 174 ft of man irons would seem to be totally impractical, and very dangerous, more pumping may reveal surprises! Would you return the water to the borehole, or dump it in the stream? I don't know what it is like in Suffolk, but in East Yorks the demands of agriculture have meant the increased use of boreholes, and susequent fall of the water table, so your borehole would not neccasarily be as productive as when last tested. OTOH if it has high iron, and is unusable as a potable supply, it could be very good indeed! Watching with great interest, and gagging to get back to my workshop!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 20, 2020, 10:07:49 AM
Sussex Phil not Suffolk - miles apart ! (The rigid fibreglass duct rod bottomed out at 53 metres)

The sign was obtained during a legitimate demolition (I am assured!)

The really GOOD thing about it being still 174 deep is that that is well below where the records say perforated pipe was installed so hopefully water will still seep in at a perfectly adequate rate for my needs.

OK so man hole & cover now transportable by fork lift (I'm certainly not carrying them!!!!) so putting them in the rear farm yard balanced on two baulks of wood, and slogging the cover via a 14 lb sledge hammer and a third block of wood produced . . .

 . . . zilch - a splintered block of wood  :clap:

Resorting to 'metal on metal' I had a very stout go at the cover, working round it's periphery until eventually the sound changed and ever so slight movement was detected. A few more really meaningful thumps and the cover dropped out of the frame. No wonder it was jammed - some serious rust had accumulated. And note, there is some pre-existing damage on the vertical rim of the cover - obviously old from the rust on it and lack of the missing bit!

Frame and cover need a good sand blasting, but I have too many other things on at the moment, and anyway too many other peoples vehicles in the line of fire.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 20, 2020, 11:26:46 AM
Nicely done!

I must admit, with the water that high in the borehole, I'm surprised you've not been suffering from soggy ground around it - The water must be no more than 6 inches under the surface?

Anyway - now you've got the lid off, it's obvious where you can drill holes for outlet and return pipes  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 20, 2020, 11:54:52 AM
Well Ade, we are always fairly damp here !

My plan at the moment is to build a low brick plinth on the concrete rings of the hole to give me head room to bring a pipe up from the pump and through 90 degrees, and to introduce the pumps cable. Also to give me something to tether a stainless wire to support the pump. Then the original man hole surround and cover can go back on.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 20, 2020, 03:36:32 PM
A good go around with the needle descaler would make some headway before the blasting! Sussex!! sorry about that, now do you understand why they won't let me cross the Humber! Can't wait to see the results of more pumping, you may have some sludge to pump out of the bottom after all the years unused, but what a result!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 20, 2020, 03:45:48 PM
Good idea using a needle descaler Phil  :thumbup:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on April 21, 2020, 04:42:11 AM
Hmm... Now when everybody is hot and poised to water/water cooling what about water to air cooling? You probably have few truck radiators and industrial fans floating around....100Kw to dissipate doses not sound much. Unless you need close to ambient temperature cooling output to start with. I have seen few hundred kW hydraulic unit oil to water cooling radiators and they were not that big (but fan was big and LOUD).
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 21, 2020, 08:26:59 AM
I think the cooling is getting sorted Pekka because . . . . .

I've been looking at heat exchangers that will isolate the furnace cooling water from the cold source water in the borehole. Many available on eBay, most seem to be Chinese, but many coming from Poland and Czech that also could be originally Chinese. Lots of amazing specifications, remarkable low prices and quality promises, and often with free delivery - but what spec do I need.

Well, in this application, erring on the large size is no disadvantage - I can't think over cooling the furnace water is an issue, and if it is I can easily throttle the cooling side feed water accordingly, so when a HUMONGOUS heat exchanger popped up on eBay, UK made, and brand new never commissioned it seemed too good an opportunity to pass up. Manufacturer was still in business, the H.E. was still a current 'off the shelf' model and the full specification was available and emailed to me - now could I win the auction  :scratch: Half the issue was that it was 'collect only' and the seller wasn't responding to my requests for contact to involve couriers.

OK auction was ending today at about 5 pm, so I put the item on Shiply  last night to get courier quotes, and then put a 'best offer' to the seller of the original starting price LESS my delivery quotes  :clap:

Surprise phone call this morning from the seller accepting my offer. Shiply courier happened to be close to the sellers location (Esher), promptly collected it and has just delivered it - well actually THEM as it turns out that there were two  :thumbup:

So what is it?  - it's a UKE BR205-50C 50 plate copper brazed heat exchanger intended for an air source heat pump. 54 mm soldered copper inlet ports and 2" BSP outlet ports. It weighs 34 kg ! and is 528 mm x 246 mm x  134 mm so I don't think there is any danger of it being under sized, and I have a spare  :thumbup:

So I still need to source a pump for the borehole, a tank for the furnace water reservoir (might come from the original chiller) and work out quite a bit of plumbing lay out with big pipes.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: David Jupp on April 21, 2020, 09:24:19 AM
And you can always use both together if you find the cooling isn't quite good enough !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 21, 2020, 10:45:38 AM
They look good, a larger version of the HW reservoir exchanger in the horrid combi boilers. I think you will heed to filter your borehole water to keep from debris clogging. It is all coming together!
Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 22, 2020, 06:15:07 AM
Yes definitely some form of filter Phil even if it's only a very fine mesh - suggestions welcome :thumbup:

This morning the last half of the foundry floor was due for its last coat of paint so that went down first thing. I had to start a second tin, and the colour was distinctly more 'elephant' than 'blue grey' but I don't suppose that it matters much  :clap:

While the paint was drying I put Phil's excellent suggestion to start with a needle scaler on the manhole castings into effect. It hadn't occurred to me for some reason, and I have to say for this application it was much less hassle than setting up the big Hodge Clemco, and made less mess. I got this needle scaler probably 30 years ago when I stripped all the paint and bondo off my Bridgeport before repainting, and I must say it's excellent. For this job I used the coarse needles - the Bridgeport got the fine ones !

It took perhaps 90 minutes to do the cover so not too bad at all. I still have to do the frame, but I came in to have a bit of a rest and upload this.

As is often the case, the casting revealed a bit of the construction of the original pattern, screw heads showing in the metal. No doubt the pattern would have had those heads puttied and painted, but in use the putty plug has fallen out.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 22, 2020, 06:27:25 AM
It seems to be often the case that a whole series of roadblocks seem to all collapse at once and significant progress suddenly appears...
A week ago, no chiller, no water, no heat exchanger. Now you just need a little pump and filter and you could be melting metal...

-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on April 22, 2020, 06:39:34 AM
If you are going to be storing the water in IBCs, Alum treatment might be more efficient and hassle free than filtration.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 22, 2020, 08:15:12 AM
NRML may have a good point there! it all depends on the amount of suspended solids in the  water after the borehole has pumped clean. I have a rainwater reuse system on the workshop which is based on an underground brick beehive cistern , probably of pre 1900 origin, which is fed by the roof water which contains leaves, bird lime, and the cidery residue from my neighbours apples which fall onto my roof! I am using a 1" pump with a foot valve which is suspended from a float about a foot below the water surface. the pump pushes water through a standard water filter. I clean it only occasionally, but it never seems to clog up. With this type of filter housing a wide range of different cartridge mesh sizes are available.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 22, 2020, 09:17:27 AM
Russ yes quite a bit of progress recently, but loads more to do. I think one problem is going to be relocating the generator, as in these lock down days I can't get someone to work with me - you can't keep your 2 metre separation when  push, pulling and rescuing errant rollers moving a few tons !

I'm hoping not to have to store water, and rely on what the bore hole can produce 'on demand' - I'll have another intensive pumping session in a few days now I've got the petrol water pump running again and see how low I can get it, and actually measure how quickly it recovers.

So after a spot of lunch I resumed work with the needle gun and finished off both sides of the frame casting. Underside is just a flat surface so was very quickly done, but the upper side is rather fiddly - it's not come out perfectly as it's proving impossible to accurately direct the needle at vertical walls in channels, but it's perfectly serviceable. To be frank were I to paint it it probably needs a quick tickle with the sand blaster but it's not at the top of my priority list at the moment.

So the to do list:

a/ Determine final location of Furnace Driver, Furnace Body (ies), Water Cooling equipment.

b/ Run single and (low power) three phase power to the appropriate locations

c/ Run water main from  bore hole to foundry in a trench (plus dig trench)

d/ Run power for bore hole pump from foundry in trench

e/ Run (high power) three phase from generator to foundry in (another) trench

f/ Run compressed air to Furnace Body location

g/ Sort out a pump / filter arrangement for bore hole

h/ Sort out large bore drain plumbing from heat exchanger exhaust to nearest surface drain

There are a few issues with the various trench / conduit runs as other services are in the way, and also concrete paths, and some plonker has just put in a substantial concrete base for an Oxy-Acetylene storage  cage JUST where the bore hole output pipe needs to go  :ddb:


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 22, 2020, 09:41:21 AM
See, hardly anything left to do. ..

As I have been heard to say on occasion, the first 90% is done, now just the last 90% to go...

-Russ
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 23, 2020, 07:33:45 AM
Having fixed the Honda WD20X petrol driven water pump it was time to do another trial pumping of the bore hole. My intention was to pump as low as possible and try and get an idea of the structure, and rate of water return.

My suction hose, complete with it's strainer and one way foot valve is marginally over 5 metres, so I was limited by that length - (of course the absolute maximum would have been 32 foot or 9.7 metres, that being the Torricellian vacuum limit for supporting a column of water)

It only took 48 minutes, shifting a calculated 27,600 litres (or 27.6 tons if you prefer) at a great gushing rate into our stream, before the pump was gulping on air having reached the end of the pipe. An impressive performance for a pretty tiny and rather old pump, and certainly an impressive gusher into the stream.

I made several attempts to take decent pictures of the inside of the bore hole, but all are pretty hard to make out - I even lowered a 240 volt LED flood light on a rope in a rather gingerly fashion, but still not too good.

The construction seems to be  24" concrete sections with integral steel steps for the first couple of metres, then it widens out to a significantly wider bore, but not concentric with the first bit, which is offset so the two circle meet tangentially.

There certainly seems to be enough for my modest 45 litres / minute for a few hours every now and again  :lol:




Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on April 23, 2020, 08:05:06 AM
Promising!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 23, 2020, 08:48:30 AM
And it looks pretty clear and clean too!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 23, 2020, 09:28:52 AM
It does have a slight tinge to it, and of course the walls of the borehole are rather brown with (??) muddy deposits, so I'd like to filter it - I'm sure it would be fine for watering gardens and live stock, but . . .my heat exchanger . . .  not sure !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 23, 2020, 01:41:57 PM
If it is high iron content, that would eplain the brown tinge , maybe build some magnets into the filtration. Back to the DHW auxillary heat exchenger on the combi boilers, the one on my now defunct ravenheat was stainless, and used to clog with the magnetite from the CH system, it used to get an anual clean out with acid of some sort., maybe include a magna clean or similar in the water line, or  a couple of round ferrite magnets in a filter housing.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 23, 2020, 02:36:23 PM
I keep meaning to lower a rare earth magnet on a thin string and see what it attracts - goodness only knows whats down there  :bugeye:

Looks like I'm going to need 32 mm MDPE pipe to get the flow rate, which is a pain as I have quite a bit of 25 mm and also it's going to be mighty  fun manoeuvring it down the hole with a heavy pump (18 kg) on the end as well as mains cable and safety rope. Might need to rig a gantry of some sort  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 23, 2020, 02:41:18 PM
Out of interest, how long did it take for the water level to recover from the 5 metres you pumped out of it?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 23, 2020, 02:58:31 PM
It's still not back there Ade - when I last looked a couple of hours ago it was back to about the lower edge of the smaller concrete sections - actually it's quite hard to judge exactly where the level is.

Last time it was up to six inches from ground level after a couple of days which make me think that there must be a bit of artesian well acclivity going on as the ground slopes away quite a bit from the top of the bore / well / whatever it is across the site and down to the stream.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 23, 2020, 03:13:20 PM
Before you go for a borehole pump, you could drop a pipe in with a foot valve, and see if you can get the desired flow rate with a surface pump, or even a waterproof pump down the hole in the bigger area. it would be a juggle to see if you can get enough water for enough time without exceeding  the 32ft limit, but weld up a good strong mesh cover for the borehole proper if you go down the mansteps!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 23, 2020, 04:07:29 PM
Those Man Steps are NEVER going to enjoy my foot fall on them if I have anything to do with it  :lol:

I have looked at 'sump pump' types and they do have certain advantages, however the advantage of a bore hole pump below the water level is that you can be sure that it will always self prime, and is unlikely to over heat - also they tend to have quite different pressure / flow characteristics. I want reliable self starting, as now the wife has an eye on the 'free water' for her green houses and poly tunnels, and to be fair it would be pretty simple to swap their feed from a mains source to the bore hole as their 25 mm MDPE pipe happens to pass close by and currently feeds seven of our twenty nine (!) outside taps
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 24, 2020, 04:19:16 AM
The bore hole is not recovering as fast as previously - it's come up a long way but it's still at least 5 foot from the surface. So I imagine that the upper strata were saturated, and when I pumped the bore down, like a sponge they released their water but now that water is no longer there, so what I'm seeing is more of a true rest level  :scratch:

It's not a problem to me as my bore hole pump will be suspended about 15 metres down the hole.

But may be a problem, and I'd welcome comments and suggestions on this, is TORQUE

Imagine a 1.1 kW long thin motor / pump assembly suspended from 15 metres of pipe / cable / stainless steel wire. It will tend to twist each time it starts and stops. In a conventional bore hole where the bore of the pipe is perhaps four inches, you can get rubber friction collars to slide on the flow pipe that grip the wall of the bore pipe to stop this. But in this situation where it's more like a well than a bore I'm not sure what is the best way to restrain it other than perhaps paddles clamped to the pump body.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 24, 2020, 08:47:54 AM
This is interesting https://cr4.globalspec.com/thread/26623/Submersible-pump-torque. The only submersible pump I have had anything to do with was a huge old Beresford  with a glass fronted cabinet star/delta starter, which fed water to the now gone Glaxo powdered milk factory (the first in the uk, installed 1934, later became Twydale turkeys processing plant) and it just hung in the borehole, under the crane that lifted it up and down. How I wish I had photos of it. Being star/delta, it started with less of a kick. Is your pump single or three phase?  Install soft start?  I searched on "torque reaction on borehole pumps" and saw mention of a "torque reaction bar" so searched on "borehole pump torque reaction bar" and got a welter of info. However, the torque reaction is going to be exerted against the delivery pipe, which you would have thought would return the pump to aproximately the same position after every start. It may be that suck it and see might be the way forward (see what I did there?) It may also be that pumping the borehole will start to bring up silt and iron bacteria slime which, after it is pumped away, may improve the recovery time, assuming the bottom of the lining is perforated, and we know has been unused for a long period.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on April 24, 2020, 10:29:39 AM
I have a similar pump on garden hose plus cable plus rope that I use to pump out a 65 foot deep pit.  I haven't had any issues with it twisting anything up.

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 24, 2020, 11:36:40 AM
I'm rather going off bore hole pumps and their complications  :(

Turns out that DAB Jet 102M pumps will self prime sitting on the surface with a suction pipe down 9 metres and deliver the flow I need. 9 metres is more than I need so my inclination is to go that way with an above surface pump and above surface controller that integrates with the pump motor.

That solution just seems easier  and safer somehow. In the mean time I've ordered 100 metres of 32 mm MDPE pipe to get the water into and out of the heat exchanger, and a whole clutch of the necessary plumbing fittings.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 24, 2020, 01:02:16 PM
Phil that is an interesting series of exchanges on that link you quoted. It was when I found the need to shroud the bore hole pump to keep it cooled when not installed in a narrow pipe that I thought that things were getting over complicated and looked harder for a suitable self priming pump.

. . . we'll see soon if it indeed CAN prime and draw from the quoted depth  :med:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 26, 2020, 07:13:12 AM
So I have a JET 102M self priming pump, control box, and 100 metres of 32 mm MDPE pipe on order along with numerous fittings - so while waiting for them I've started dismantling the defunct refrigerated chiller to rescue various things such as it's reserve tank and Grundfos pump. The case I will probably scrap, or possibly cut down into a smaller unit to re-house the tank, Grundfos pump and new heat exchanger. The jury is out on that decision at the moment.

However to sort my ideas out and make sure I've not forgotten anything I have re-worked the 'overview' diagram, as it gets a bit complicated what is fed from where - don't want anything overlooked while trenches are open !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on April 26, 2020, 08:42:25 AM
It seems like it shouldn't be an issue, but could you return the well water to the well? The sheer mass of the well ought to be able to keep the temperature rise under control, and there is no chance of pumping exceeding the supply rate.


-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 26, 2020, 10:57:58 AM
Russ I had considered that but decided against on simplicity grounds - pipe length is about the same as I'll be using a roof gully that's about 20 metres away - I had considered running the waste water down the gutter of the welding shop roof to save 20 metres of pipe but that just seems crude !

So the task this afternoon has been to dismantle the old water chiller unit - no major complications except that it must have been assembled on a stand in the factory, as everything is fixed with nuts and bolts to the base and there is barely enough room to get a hand under. In the end I jacked up one side to gain access only to find that the tank wasn't quite empty and I was pouring loads of grubby water on the floor  :bang:

Having spent an hour with an old towel mopping up round all the obstructions what is left can (I think) be left to evaporate - well over a gallon mopped up!

So I now have the Grundfos CH4-60 pump out and this will definitely be reused. I have the insulated nylon cold tank removed, that is crammed with refrigerator gubbins all of which should remove quite easily - this I probably will reuse.

The main casing is huge - I need 'something' to house the Grundfos pump, tank, and the heat exchanger along with a three phase contactor and a few water valves, filters and connections - cutting it down may be more trouble than it is worth, but I may well reuse for instance its corner upright members to create a somewhat more compact unit.

The upper part of the cabinet still holds the original temperature controller and its contactors, and also two huge slabs of cooling radiators and a big three phase extractor fan - these all will need removing tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 27, 2020, 09:10:26 AM
My days began with the best of intentions to carry on dismantling the old chiller and recover anything worth saving, but first one of those '5 minutes jobs' got in the way:

. . . Identify what model of Briggs & Stratton engine my ancient 2 kW generator has, and order a replacement ignition coil. Well the model number is stamped into the cowl Google tells me, and I'm sure it once was, but at least 30 years of rust and Hammerite have rendered it illegible even after much cleaning. Looking at pictures on the web I'm pretty sure that it's a 3 HP 80232 with a 'points and capacitor' set up - coil is O/C. Almost identical ones available on eBay and from gardening on line shops BUT their mounting holes are 64 - mine is 59 mm  centres :bang: 64 mm one ordered and it looks like some machining is in order to modify the replacement, but those holes are through the lamination so that's going to be fun!

So at last back to the chiller - I've decided it is not worth re-working the case - I will make a skeleton one out of heavy box tube giving a much smaller footprint  so no point in more case dismantling - the scrap recipient can do that!

So I removed the entire control box with it's various useful breakers and relays, and also the huge extractor fan that sat on the lid, and then turned my attention to the water tank.

An angle grinder took care of the internal copper plumbing allowing me to remove the copper evaporator as a complete unit (lucky scrap recipient - it's heavy and solid copper!) and then cleaned the tank using my petrol pressure washer - it's not come out too badly.

This tank is 110 litres /  or 24 UK gallons so reasonably sizeable - I think a frame about 30 x 24 inches should accommodate the tank and pump on the ground floor, with the heat exchanger and other controls a bit higher up. I ordered some cheap imported LED temperature indicators on ebay so that all ports of the heat exchanger can be monitored - so a front panel mounting them, the start / stop for the pump and anything else I've forgotten can be up at eye level.

While all this was happening the pipe and plumbing fittings were delivered - so a quick goods inwards check to see that it's all there - yes it is but I'm sure I've forgotten something - always seems to happen with these projects!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on April 27, 2020, 04:08:31 PM
It would be nice to turn all that copper into bronze as your first melt.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 27, 2020, 04:40:00 PM
It would be nice to turn all that copper into bronze as your first melt.

I have a chap who is very generous with his time helping me with things that anno domini is making more difficult as the years go by. He is scraping a living in agriculture not very successfully so I let him have my scrap as he always refuses to take payment. This way I can disguise it as actually helping me get rid of junk  :thumbup:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 28, 2020, 04:13:37 AM
It would be nice to turn all that copper into bronze as your first melt.

You beat me to it....  I've got a pile of solid 6mm copper wire here for the old overhead gantry crane  - which, to avoid coils of wire hanging around the place, literally ran in similar fashion to a railway train, with 3x bare conductors and sliding pickups), if I ever get Rob Wilson's old furnace going, I'll definitely be making some copper ingots...
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 28, 2020, 05:05:19 AM
Funny stuff to cast, copper. Very fluid.

Pouring down here and I’ve just been out to the ‘soon to be’ foundry to find numerous leaks in the roof :bang:

It’s a fibre  reinforced cement ‘big 6’ roof in good condition only 10 years old but laid to a fairly shallow pitch. Leaks are at sheet overlaps so I’m hoping that maybe there is a build up of leaves from a large tree close by. Too much rain to look at the moment. Don’t fancy drips into the high power electronics  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 28, 2020, 06:24:27 AM
The rain has subsided to an annoying drizzle, so I was able to put a ladder up and look at the foundry roof. Sure enough there IS a bit of a build up of moss and  rather too much overhanging willow tree. I expect that the water isn't clearing fast enough and is tracking back up the overlapping joints when the rain is heavy.

Talking of heavy rain - the bore hole is now OVERFLOWING  :bugeye:

The Black Jack to paint the newly cleaned manhole frame and cover has arrived, but that can't go on until the weather changes.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on April 28, 2020, 11:13:05 AM
Odd that a borehole so deep should react so fast to rainfall, but no matter, it is all to the good as far as the project is concerned!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on April 28, 2020, 11:50:30 AM
Well, that explains why the lid was so rusty - it's probably been being soaked from the underside on a regular basis for the last 50 years!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 28, 2020, 12:55:27 PM
Probably so Ade !

I'm hoping to be able to incorporate an overflow pipe at the level of the lowest brick course. I happen to have a run of perforated ground drain not very far from there, (albeit the other side of a Portakabin) that joins into the main run of surface drains to the stream - with any luck I can intercept it and join in.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on April 28, 2020, 04:10:19 PM
There must be some artesian well type of effect taking place. Is there anything in the local geology to explain this?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 28, 2020, 04:56:50 PM
Not really - OK we are pretty well towards the bottom of a very shallow valley - but it's all pretty clayey - the bore hole is at a low point in the goose area so it could just be the massive downpour that we had.

. . . an over flow . . .that's what's needed  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on April 28, 2020, 06:11:24 PM
Not really - OK we are pretty well towards the bottom of a very shallow valley - but it's all pretty clayey - the bore hole is at a low point in the goose area so it could just be the massive downpour that we had.

. . . an over flow . . .that's what's needed  :clap:

Looks like you got one :D
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 29, 2020, 05:10:05 AM
So this morning it was a case of "out with the old, and in with the new".

Old Chiller chassis palletised and dragged out to make a bit of space, I did save it's castors as it was easy to when hoisted up with the forklift!  And then I finished off cutting the box tubing for its replacement that I started yesterday. I need to clear space in the welding shop before I start putting it together - of course sods law dictates that it's slightly too large for my welding bench !

Meanwhile intensive tree pruning to remove branches overhanging the foundry roof - personally I'd just fell the tree, as it's only a scrubby willow but it's not on my side of the boundary. I'm sure the water board (who we neighbour) would have no issue with me introducing it to a chain saw, but getting to speak to the right person is neigh on impossible.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 29, 2020, 11:02:38 AM
Raining hard again this afternoon, so the welding shop didn't get reorganised (much easier when things can be temporarily be moved outside)

But I did strip the peeling paint off all twelve cross members ready for welding. I didn't do the four uprights as they will be far easier when the bench is moved to a more convenient place - hopefully tomorrow.

I used grizzly stripping disks - these take paint off at a great rate of knots  and are slightly kinder to the underlying metal than coarse sanding disks. They are also EXCELLENT at taking the skin off your knuckles! Amazingly I found that I had a box and a half in stock from some other project. Used three so far.

These box sections are very heavy dip galvanised and I wanted to leave as much zinc on them as possible.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on April 30, 2020, 10:24:32 AM
A major push this morning to dig my welding bench out from the accumulation of encumbrances that have  built up around it - various  welders (which I suppose are justifiable next to a welding bench!) and other junk not so justifiable.

Then finding a home for the multitude of clamps that normally sit clamped to the edge of the bench, and removing the very heavy vice, and a pile of rather nice fire bricks (thanks Pete. !) I was able to pull it out to a position where the frame that I'm about to weld up can hang over the edge, and be worked on all round.

About then my oil boiler man turned up to service  the three systems we have on the farm and repair the oil level monitoring system, so activity had to cease.

I did however manage to plot the route of the ground drain that I want to intercept for the bore hole overflow, and start the digging of a trench from the bore hole to the fence, the other side of which the drain runs about three foot out. I have a 'CAT and Genny' - ie a Cable Avoidance Tool which is fine for metal pipe and cables but not plastic pipes. So again my 250 metre long reel of fibreglass ducting rod came in handy, tying a random length of wire to it, and threading it down the drain, attaching the other end to the genny. Worked an absolute charm. (Picture rather fussy - rain pouring down - taken from under an umbrella !)

Hopefully tomorrow will see the four frame uprights paint stripped and welding can commence.

(later edit: for the record so that I can refer back to it if I need to, the detected field drain is 69 " from the face of the fence)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 01, 2020, 06:09:12 AM
I was determined to get the four six foot long upright box sections stripped of their paint today, so grabbing a cold (cooked!) sausage in lieu of breakfast I got out early before other things distracted me.

Four stripper disks later and about an hour and a half of angle grinder time not only was EVERYTHING covered in paint dust but the uprights are at last stripped.

. . . let the welding commence  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 01, 2020, 09:36:25 AM
I'm sure this job is jinxed  :bugeye:

I had set up for the first weld and then was conscious of a hissing sound  :bang: A bit of hunting about and I found that the plastic upright tube of my 'Peashooter' Argon flow gauge was leaking where it screws into it's base / tap / outlet thingy.  At £160 per bottle leaks cannot be tolerated !

Fortunately I was able to unscrew it by the expedient of wrapping a bit of 200 grit wet and dry round it and gripping in the lathe chuck, expecting it to crack at any moment. It unscrewed  suddenly with a flurry of ball bearing / inner tube and odd shaped plastic spacer falling in the swarf !

OK it just needs screwing together with something to seal the threads. Being plastic I'd usually use PTFE tape but getting the ball, inner tube and spacer in necessitated partially threading it on first so non too easy with tape. I resorted to Loctite 542 that says on the bottle 'do not use on plastic fittings' - well I did !

It needs a bit of time to cure, so I stopped for an early lunch. After about 45 minutes it seemed at least partially cured so I re-assembled it on the regulator and resumed welding.

All went reasonably well. I've finished the first 'frame' which could be front or back, left or right as it's symmetrical.  Not surprisingly there is a bit of a twist in it, only about 8 mm but I should be able to pull it back when it's got the rest of the bits welded to it.

I'm quitting while I'm ahead and will resume tomorrow as the oil boiler man is due back this afternoon.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on May 01, 2020, 10:20:40 AM
Looking good so far.  :clap: Do you use anything special when welding galvanised steel in the way of breathing apparatus?
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 01, 2020, 11:21:20 AM
Wide open doors both ends of the welding shop and hope the fumes clear before they get you !

The galvanising certainly gives a greater tendency to porosity, and the flare from the burning zinc when the arc starts can be a bit distracting. If these were critical welds I'd strip the zinc with acid first but they aren't. As usual it's massively over engineered!

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete W. on May 01, 2020, 02:45:51 PM
A one-time neighbour of mine worked as a welder.  I asked him about welding galvanised items and he said the thing was to drink lots of milk.

Is that founded on reality or is it an old wives' tale? 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 01, 2020, 02:56:54 PM
A one-time neighbour of mine worked as a welder.  I asked him about welding galvanised items and he said the thing was to drink lots of milk.

Is that founded on reality or is it an old wives' tale? 

I can't remember why, but it really does work!

Regards, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 01, 2020, 03:33:10 PM
Yes I've heard that as well, but I just went and drank copious cups of tea  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on May 01, 2020, 03:45:24 PM
Milk is a source of calcium. The belief was that calcium would act as a chelating agent reducing the damage caused by the metal in the body. Unfortunately, it isn't true.
https://safe-welding.com/milk-against-welding-fumes-not-much-more-than-an-old-wives-tale/
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on May 01, 2020, 05:59:10 PM
Snippets appreciated. :thumbup:
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 02, 2020, 12:04:44 AM
Milk is a source of calcium. The belief was that calcium would act as a chelating agent reducing the damage caused by the metal in the body. Unfortunately, it isn't true.
https://safe-welding.com/milk-against-welding-fumes-not-much-more-than-an-old-wives-tale/
nrml,

Thanks for your link! So I was wrong! I've been trying to remember where I'd heard about milk for fume fever. I've come to the conclusion it was nearly fifty years ago when I trained a mechanic, we had gas welding in our training, so I'm sure it was then, as I've had very little formal training in welding! I have had fume fever from welding galvanised steel, milk certainly feels good when it goes down, but OK, that's all it is then!!

About ten years ago I had mild heavy metals poisoning, abnormal levels of Lead, antimony, Cadmium, mercury, Aluminium and arsenic! (Arsenic is not a metal, but is grouped in with the metals as it is the same kind of poisoning) The lead was explained by untested well water in Wales, but the rest was unexplained! I was treated for it. I discovered that fresh Coriander is a natural chelation, so I regularly treat myself to copious amounts in my diet! Coriander should also work for fume fever!

Regards, Matthew

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 02, 2020, 05:52:20 AM
So this morning it was just a case of 'rinse and repeat' - make another frame like the first - simples !

. . . well yes simple if you clamp the first corner the right way round - I had the two bits in the wrong orientation - the short bit should be a stretcher between the long bits, not the other way round. Of course I only noticed when I'd welded it  :bang: Never mind, the work of a couple of minutes to cut the weld, grind back and glue it back together the right way  :clap:

After that all went well - I had a bit of an issue getting the last corner to join, and had to resort to extreme measures welding dogs to the table and using wedges, but I got there in the end.

OK so that is two frames made, and this one is remarkably square. The next thing to do is to weld another set of six stretchers to make this last frame into a table like structure - I just need to work out how I'm going to jig and clamp them to get everything mutually at right angles.

It may just be a case of holding it, tacking it, bending it square and finish welding  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on May 02, 2020, 10:32:27 AM
...resort to extreme measures welding dogs to the table....

I bet the dogs weren't thrilled about that!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 02, 2020, 11:06:31 AM
We don't take prisoners here Ade  :lol:

So the forecast for this afternoon was fine for once so I decided to do the 'outside work' of intercepting the land drain and connecting the over flow from the bore hole to it.

Very tentative scratching away with the JCB 803  eventually exposed it without ripping it apart - amazing how quickly the tooth of an excavator bucket can do a lot of damage to services  :bugeye:

Then spade work exposing enough to inset a 45 degree branch for the overflow, surround in pea shingle and back fill - fairly simple but awfully sticky wet and muddy!

Once that was done, it was back to the bore hole to cut a slot in the two top courses of bricks to receive the new pipe. I was very surprised how hard and resilient the bricks and mortar were - took far longer than I'd expected.

Then I pumped the well down a long way to give the mortar that I was fixing the pipe in with a chance to go off without being swamped. No doubt I'll have to run the pump a few times before the mortar is reasonably hard.

The outer farm yard is now a bit of a mess and churned up - it all needs to dry a bit for the scars to clear!

. . .but I do now have a nine inch length of blue land drain  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 03, 2020, 07:30:27 AM
So I did go out at about 8 pm last night and re-started the pump - level was no where near the mortar but might as well give as much free board as possible for overnight.

I noticed that the suction hose was curling under water so not as long as it could be (at night with a torch you can see more down the 'hole' than in the day time) so I gave the hose a shake to straighten it and was just walking away when I saw that the pump, with it's vibrating engine, was walking towards the lip of the bore hole and quite likely to plunge to it's doom pulled by the weight of the 2" suction hose  :bugeye: So I pulled it back a bit (loosing suction hose length) and baby sat it for a bit.

This morning the mortar is rock hard - I deliberately made a hydraulic mortar  (IE excess Portland cement) so I'll let it fill back up to level.

I was very pleased to find that the 90 degree welding clamp that I've been using will accommodate a 'three ways meeting'  of box section - only two ways are forced to 90 degrees so a large square was used for the third axis.

The six stretchers that will be horizontal when the chassis is stood upright, are now welded to one frame. I now need to lower that to the floor with the stretchers horizontal, and offer up the second frame for welding, but that probably will be tomorrow. It's getting blooming heavy !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 04, 2020, 10:54:25 AM
Today I assembled the 'table' part of the frame and the second frame, pulling them into alignment with various clamps including three sash cramps borrowed from the woodwork shop.

Having got the upper joints welded and the lower ones tacked I then rotated the frame to present the lower joins as 'in position' welds. This zinc tube is awful to weld at the best of times, especially 'vertical up' for some reason, and it pops and bangs all over the place.

Once all welded I got my ever helpful CNC Plasma Table to cut me some plates to take the original castors off the previous chiller. These were welded on, drilled and tapped, and the castors bolted on.

A bit of grunting and it was set on it's castors ready to be fitted out with it's equipment. I'll do a 'dry fit' of everything, then break it down for spraying before final assembly.

Quite pleasing that as it is now is entirely made from re-cycled materials.

So next I need to make a base plate onto which the tank and Grundfos pump will mount, and sort out how I am going to mount the heat exchanger and other bits and bobs.

Meanwhile the Manhole Cover and Frame got a coat of black bitumastic paint to keep the rust at bay.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on May 04, 2020, 04:14:54 PM
Tsk, tsk. Poor show Andrew, you didn't repair the damage to the cover  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 04, 2020, 04:52:19 PM
A friend wanted me to drill it and put eye bolts in, until I pointed out that it had key slots and eye bolts would be a dreadful trip hazard!

And no, I didn't weld up the bite out of it - it's been bad enough welding that heavy galvanised box section with all the popping and spluttering and porosity that it gives without trying malleable iron !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on May 04, 2020, 06:41:14 PM
How long does that bitumastic paint take to fully cure? Is there a risk it will just glue the cover into the frame?

-Russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 05, 2020, 02:21:37 AM
It was touch dry in less than an hour. It has a reputation of being hard to brush, so I left it in a bowl of hot water for an hour before I opened the tin. In fact it was no problem as quite fluid but I suppose it probably can be a bitch in cold weather.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 05, 2020, 10:09:22 AM
This morning I cut a 750 mm square 'bottom shelf'  (with notches to accommodate the verticals) out of 6 mm plate on the CNC Plasma table.

Why as heavy as 6 mm  :scratch: Two reasons -  A/ I had a handy bit and B/ 6 mm is thick enough to drill and tap and not have to bother with nuts in hard to locate places.

This allowed me to do a 'dry fit' of the tank and pump, and (although not in the picture below) also the huge heat exchanger balanced on a plank on the middle rails. This was to better let me work out pipe runs and place yet another big plumbing bits order  :bugeye:

The issue that I have now is that one side of the heat exchanger is male BSP, but the other is a 54 mm stainless steel socket intended for soldering in copper pipe. Now it is a massive heat load to solder, and I'm not sure what solder and flux you'd use with those metals - any suggestions welcome.

I rang the manufacturer of the heat exchanger for advice and I'm waiting for their technical people to get back to me but I expect that's not going to happen any time soon  :(

I also asked what the price was of that model - £500 plus - glad I got them on ebay not off the shelf  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 05, 2020, 11:26:46 AM
Hi Andrew,

I would silver solder stainless to copper, soft solder would work; but I think silver solder would be better!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on May 05, 2020, 11:35:04 AM
I think that it would need to be silver solder. The flux needs to be quite aggressive, too.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 05, 2020, 12:03:08 PM
Trouble is that it's a blooming great heatsink!

I'm wondering if something like Permabond 910 would work. Recently there have been several bonding glues put on sale but all specifically say for copper plumbing and I can find no mention of any other metals.

But Permabond 910 is specifically for bonding metals including both stainless and copper, but abrasion is recommended presumably to give a better physical key.


https://www.permabond.co.uk/product-page/permabond-910-for-metal-1-x-20g-bottle
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on May 05, 2020, 05:00:19 PM
Soft solder might be a good starting point. It would need lower temperatures to get it to flow. Seems to be very popular for stainless steel in the small scale brewing circles.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 05, 2020, 05:32:50 PM
Yes that's my preference as the temperatures are more easily attainable, but I'm not sure what flux is aggressive enough for stainless. I've seen one based on phosphoric acid and others based on zinc chloride. I've also seen a video of someone using 95% tin 5% antimony solder but can't source it this side of the pond.

Obviously I have access to normal 60/40 lead tin, and the new 'lead free' solder - I did an experiment on a stainless fitting with the lead free and it's normal plumbing flux but it wasn't very successful.

Zinc chloride is supposed to be good but apparently a bit nasty fume wise and needs a good post operation flushing.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 05, 2020, 05:54:55 PM
Andrew,

Pure zinc sheets are used a lot on roofs here. The French Zinc workers flux which I've used successfully on a wide variety of metals including stainless, is made by putting small bits of zinc in a glass jar, you then add hydrochloric acid, let it fizz, set fire to it and then smother to put it out! It's a nineteenth century method that works really well, sounds like your zinc chloride! I would favour the 60/40 over the 95%tin 5%antimony it will flow better!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 05, 2020, 06:01:03 PM
lead free is piss poor Andrew, SS is a fairly poor conductor of heat, if you can get some flux for SS, and it should be a plumb centre item , I would use ordinary plumbing solder, the copper will pull the solder in and when the ss is hot enough it will be done! might need mapp, but you also have O/A! a google produced this:

Stainless steel can also be soldered or brazed to itself or to brass or copper, with good results. These processes provide good alternatives to the welding of stainless steel fittings.
But personally, I would solder it, as you can see the solder drawn into the joint, and add more, whereas the brazing metal tend to sit on top in the gap between the pipe and the boss, and could crack given the vibration from the pump. Long shot, but could you put a thread in it, and make up a bush to suit your plumbing sizes?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 05, 2020, 06:07:46 PM
Matttinkers flux is "killed spirits" AKA "bakers fluid"

I have just been shouted from upstairs that the maths lesson the wife was conducting on our bed with youngest daughter is now over, and tea and coffee is required, knowing full well which side my bread is buttered on, I am off to do my duty, Laters, as the young ppl say!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on May 05, 2020, 06:58:18 PM
I would use "acid flux" for plumbing.  Its Zinc chloride.  I would scour the places you want to solder on the sst to bright metal, then glove up and sand it again, Wetted with flux. 
I would pro-gun the sst by itself, so you can be 100% sure that you actually got it to wet.  Once that's done, it's any easy.soldeting job to stick on the copper.  Lots of cleaning, of course...

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on May 06, 2020, 05:32:58 AM
Hi Andrew

I was a bit surprised when you said you couldn't get 95%tin 5% antimony solder.  I thought that was lead free plumber's solder - well maybe it was when I last looked - it was one of those handy bits of information - like you could use it for mending aluminium.

Anyway I did a bit of searching.  The key thing for searching seems to be that it is grade 95A.  I found several UK manufacturer's sites listing it who might be worth a call, but the only place I found where you could order it on line was here but in the wrong form:

https://www.soldersonline.co.uk/search.aspx?search=95A (https://www.soldersonline.co.uk/search.aspx?search=95A)

While looking at that site I also saw that they list fluxes for stainless, here's one:

https://www.soldersonline.co.uk/detail.aspx?id=110 (https://www.soldersonline.co.uk/detail.aspx?id=110)

They also list solders for stainless.

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 06, 2020, 07:17:58 AM
Looking at my roll of 'lead free' it is 'alloy 23' which seems to be tin with a trace of copper

I've ordered some Zinc Chloride flux from CUP alloys - apparently can't be posted so incurs a courier charge.

My temperature gauges arrived for monitoring the ins and outs of the heat exchanger - I need four so I ordered five to have a spare - I left three of them hooked up over night to see how consistent they are - not hugely is the answer but probably OK for this application.

Today I drew up and cut the mounting arrangement for the heat exchanger having first balanced it on a plank and tied it on with baler twine to prevent it leaping to it's doom. Again I cut the bits out of 6 mm plate as it was already on the machine - cocked up and failed to re-set zero on one part and overcut a previous one, but no great issue just cut another !

I intended to clamp the H E with 8 mm studs as I was sure that I had quite a few lengths of it. Where it's gone is a mystery so I had to use 12 mm which is definitely overkill - (this thing will never escape!) and it had the disadvantage that there was no longer room for nuts to retain the studs when not in tension, but never mind that's only ever an issue when installing and removing the unit, which hopefully will not be too often.

So all in place - plumbing bits due to arrive from BES this afternoon so I can hopefully complete the dry fit but meanwhile as all the components for the bore hole pump and control have now arrived I'll try and assemble that while waiting.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 06, 2020, 11:20:59 AM
So this afternoon I unboxed the Bore Hole Pump and its controller and wired them together.

The pump is cast iron with 1" BSP female ports, but the controller, although male 1" BSP is the dreaded PLASTIC threads - horrible things and so easy to cross thread when you have a wrap of PTFE tape over them - give me metal threads any day!

They obviously intend that the suction side is on the left whereas mine of necessity is on the right - this means that I've had to orientate the controller at 45 degrees as two faces of the controller need to be visible from the front - the indicators and buttons on one, and the pressure gauge on the other.

As a consequence the priming plug (hey this is supposed to be SELF PRIMING!) is even more difficult to access than were the controller set in its intended position.

I may extend the controller upwards with a bit of stainless pipe, and may even dress the suction hose round to the right so it all sits as the makers envisioned as an extra metre of pipe probably is of no consequence.

Having assembled it - time to do a test - so once primed with the fussy plug it went splendidly - I fitted a stop cock to the output to test the auto on / off function and also make measuring its delivery rate easier. A 3 gallon bucket filled in 16.09 seconds so I make that 51 litres / minute which is above my estimated 45 litres / minutes for adequate cooling. Mind you that was though a relatively short length of pipe.

Now to give serious consideration to building something to house it next to the bore hole.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on May 06, 2020, 01:15:12 PM
If you have the heat exchanger almost submerged in a vat of hot (almost boiling) water, it might be easier to keep the heat in the joint while soldering.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 06, 2020, 02:48:14 PM
Does it suggest using a foot valve with this pump, or is it truly "self priming"? I have a foot valve on mine, even though it is only about a metre at most from pump to water surface. I use the foot valve with a large stainless ball that drops into a rubber seat. Good valves, but the can stick if the water gets a bit sticky, like mine does with the aforementioned neighbours apple problem!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 06, 2020, 03:43:27 PM
It has a foot valve incorporating a filter screen.

Been measuring up for a slab to build a kiosk for the pump. Size determined by a 900 x 600 mm flag stone that will form the roof. Need to hunt around for some  timber for form work.

A friend is coming tomorrow after work to use his diamond saw to cut across a concrete path to feed power to the kiosk, and a 25 mm pipe to connect to the horticultural taps. Path is about 9 foot wide and laid in panels, each panel joined to the next with cast in situ rebar. Plan is to cut across at a join leaving the rebar intact, breaking the concrete away underneath and threading the pipes & cable under the re-bar before making good. This way hopefully the slabs will move together.

This is the slab before laying in March 2009 - you can see the re-bar and the bore hole manhole cover is just visible behind the concrete mixer!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 07, 2020, 11:04:01 AM
A bit of a scrappy day today - odds & sods. I had to make room to cut the slot in the concrete, which involved moving the large blue plastic barrels of glycol solution that I've been keeping for re-use all this time - trouble was that pallet had rotted and by heck they are heavy to shift onto new pallets. This is the second time in thirteen years that they've been re-palleted !

Also went hunting for shuttering timber for the small slab for the pump dog house - found some scaffold tower boards with rotten ends that will still be long enough when trimmed.

Then I redrew and cut a replacement 'bottom shelf' for the new chiller. I've never been happy with the fit of the old one. Now is the time to sort it as I'm about to make the fixings for the tank, and bolt the motor down. So sort it or put up with it! The frame is not exactly square so I had left a rather large wiggle space where the notches for the frame uprights are. Well today I experimented with a very large and stout sash cramp that I have to see if I could pull the frame square - yes I could although of course it springs back without the clamp. A bit of 'over squashing' improved things - better but not perfect. So I drew up another base with only 1 mm excess space for the uprights. It went in slightly reluctantly and is holding the frame square. Twelve M8 bolts later and it's fixed down :thumbup:

All will need  dismantling for painting but at least now it looks OK to put my name to!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 07, 2020, 03:04:02 PM
So my friend came round after work with his diamond saw and deftly cut a slot through the concrete path avoiding cutting the re-bar that joins slabs. We were able to clear enough space below the bars to slide two lengths of  40 mm waste pipe to act as conduits for the SWA cable that will power the pump, and a 25 mm MDPE water pipe that will branch off the pump output and feed the horticultural areas.

Next he cut another slot in the rim of the borehole to be one brick course above the overflow. This again will take two lengths of 40 mm waste pipe, one for the pump suction pipe, and the other for the return water from the heat exchanger that will be tucked down the overflow.

Bless him he is returning on Monday evening to make a start on the pump house, that will be based on a 900 x 600 mm flag stone and about 12 courses of bricks high.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 08, 2020, 12:04:41 PM
Another bits and pieces day. I wanted to finalise my plumbing order from BES because I have decided to go with 68 mm down pipe tube as the conduit from the new slot in the well to the 'pump house' to take the actual suction hose - the 40 mm was a bit tight for the hose. Now I had a suitable bit of 68 mm down pipe but no 90 degree bend (well actually 91.5 degrees in rain goods!) to take it from below ground into the pump location hence having to order and I might as well sweep up the rest of the bits needed.

Trying to concentrate on what was already to hand and allocated and what was on shortage proved impossible with a flock of geese honking and people milling about shearing sheep so I used the expedient of threading allocated bits of plumbing on baler twine and tying them where they will be used - I think I got there in the end but interruptions like 'the power is off' when in fact a shearer had plugged into but not switched on a socket tried my patience that was getting shorter by the minute !

OK order placed - next job check that I have enough SWA cable and appropriate glands and pick a source and a route - done (tick)

Next check where I will be able to cut the feed to the horticultural taps and connect them to well water. This involved a bit of digging and to my horror I discovered an underground Tee joint and branch that I had no recollection of (but I must have installed it!). A lot of faffing about, turns out one pair of taps must have been connected before the rest, and before these concrete slabs were poured, but the routing of the new feed and isolation of the old shouldn't be an issue. Done (Tick!)

Next - sort the overflow fitting on the chiller tank. This is solvent weld and of a size not easily available, so I cut the old tank connector, mounted it up in the lathe and bored out the stub of old pipe so that I can re-use the fitting with a salvaged length of the old pipe. Done (Tick!)

Next - dry fit the connection from the chiller tank outlet to the Grundfos pump so that the location of the tank is set. Done. (Tick!)

Next - make four 'tank location brackets' - drill and tap chiller frame base and fit brackets  refit tank - done (Tick!)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 09, 2020, 05:58:36 AM
First job this morning was to bump out 120 bricks and two 900x600 flag stones ready for when my friend arrives on Monday evening to make start a start on the 'pump house' masonry.

Then taking my life in my hands I decided to have a crack at soldering the big 54 mm connections that I've been so concerned about. At the time of soldering it needs a flow and return 28 mm pipe already in the reducer so that they could be all done in one 'heat'. A bit of a mock up first to make sure that the 28 mm pipes were the correct length, and a bit of adjustment in the lathe with emery cloth as they were a bit too tight for comfort in the 54 mm to 28 mm reducers. I suspect that this is actually Imperial 1" pipe not 28 mm - I've had it a long time !

So all cleaned up, heat exchanger on the welding bench solder and flux to hand, my big butane torch set up and my small propane torch to hand (my concern was getting enough heat into the beast) and off we go. All joints fluxed up, both torches on the first joint and we are getting there :thumbup: Solder started to flow nicely - a wipe again with the flux brush and a tad more solder and the joints seem good. Rinse and repeat on the second side, let it cool, take it outside for a good forward and reverse flush out to hopefully get rid of the zinc chloride flux, a blow out with the air line, and refit it to check that I got the pipes in the right holes and of the right length - phew yes  :clap:

As you may imagine completing the soldering on these big 54 mm joins is a big weight of my mind - the rest is more normal sized plumbing.

Time for a coffee    :coffee: :coffee:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 09, 2020, 09:42:20 AM
After this mornings excitement I had an easy afternoon, just cutting a top cover / lid thing for the chiller frame to keep the muck out if it has to go back into the foundry before the roof is fixed. Just a 750 mm square of 1.2 mm Zintec sheet with twelve holes in, and appropriate holes drilled and tapped into the top of the frame.

I actually cheated, and used the drawing for the 'bottom shelf' but deleted the notches for the uprights as they are not needed as it sits on top. I must have made a slight error in the original drawing, as to my surprise the hole pattern isn't symmetrical. I've suitably stamped the frame and panel so I can get them back together after painting, and must remember to do the same to the 'bottom shelf' before it is removed for painting.

Out of curiosity I'm now off to look at the Autocad drawing - not that the error matters one jot !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 10, 2020, 07:46:21 AM
With the latest plumbing order not expected until Tuesday / Wednesday it's time to turn my attention to the electrical requirements of the cabinet. Faily simple really:

16 amp / 3 phase input socket
3 phase on / off switch
Motor starter / over current unit for pump (salvage from original chiller)
12 volt DC supply for temperature indicators (already have one)
A few DIN rail bits and terminals (got)
A box to put it all in

Now the box - could I use the one from the original chiller? It's really too big, and rather rusty. Too big doesn't matter, and the rust is no major problem so long as the paint on it will 'feather edge' as I don't want to have to strip all the paint off.

So I started stripping out all the electrical gubbins from the original cabinet, and when I had a bare box did an experimental de-rusting with a sanding disk, wire wheel and stripping disk. I decided that it actually was feasible, so giving it a good clean up I've given it a coat of hammer finish blue.

Some of you might think that the paint scheme is remarkably similar to that I used on the 110 KVA generator - there's a good reason for that  :clap:

I've not sprayed the door as I need to make holes in it for the temperature indicators and also a door interlock switch that I have ordered that will double up as an on / off switch
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 11, 2020, 10:43:22 AM
This morning I cut the front panel with an aperture that will take the electrical box, and two brackets to support it in the same way it was supported in the original chiller.

I'd intended to just spot weld the brackets to the front panel - both are 2 mm zintec sheet, and as soon as they flexed the welds were giving way, so I replaced the welds with an over abundance of screws !

Jury rigging a temporary support I was able to do a test fit of the box in the hole - now I can mark the brackets for the final mounting screws that go in the sides of the box.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 11, 2020, 02:00:45 PM
So my friend came round after work and we dug the footings and filled them with concrete. The idea is to come up in brickwork a couple of courses, lay lintels across the pipe runs, come up a few more courses in brickwork then lay the lower slab. Then onto this build up in brickwork to a suitable height to easily house the pump and leave working space before putting a second slab on as a roof.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 12, 2020, 02:07:10 PM
So I started the day reorganising the well pump fittings to raise the controller sufficiently that the priming plug is more accessible, and getting the suction and flow fittings in the correct orientation. This is so that the slab can be marked out for core drilling.

Then knowing that the manhole frame can soon be concreted back I made a pair of lifting handles to more easily re-fit the cover.

This done my friend returned and set the first few courses of brickwork. Two below ground to take the lintels, and the two above onto which the first slab will be set - hopefully tomorrow.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 13, 2020, 12:26:06 PM
I've been working out pipe runs inside the new chiller unit today, having decided to run everything in 28 mm copper rather than the 32 mm MDPE as it is a bit more stable.

Amusingly my rolls of 32 mm DIAMETER  MDPE pipe say 32 mm RADIUS  printed on the side! - I can assure you that it isn't  :clap: Someone in China is perhaps confused  :scratch:

My friend made good progress this afternoon with the brickwork. First cutting a suitable hole in the the lower slab for the pipes to pierce, and also a 'drip line' on the underside. Then building up the brickwork to 3 courses from finish height. Three more courses, a roof and a door and it's finished

I had to do a test fit of the pump naturally !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 13, 2020, 03:55:42 PM
are you going to drop a piece of plastic drainpipe over the wires and pipes between the slab and the ground to stop the critters chawing on them?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 13, 2020, 04:41:06 PM
The 'suck' pipe will be enclosed in 68 mm down pipe all the way from the well to the pump compartment, The output, which will be 32 mm MDPE will be in a short length of similar pipe just for the vertical bit. The SWA cable probably will be ok but now you mention it I may sleeve it with 40 mm waste pipe.

In the wife's chicken shed I had to run the 25 mm MDPE water pipe through a bit of scaffold tube as the rats ate it  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 14, 2020, 03:27:10 AM
Last night I drew up a substantial 28 mm pipe mounting clamp and set it 3D printing a pair on the Cetus in ABS. 8 hours and 14 minute job so left over night churning away.

I need substantial clamps for where the four pipes leave / enter the chiller unit and have hoses dangling on them - no easily available plumbing type clips are heavy enough duty.

This morning the first pair were printed and came out OK  apart from a bit of de-lamination of layers near the through holes - (for an idea of scale the through holes are 10 mm). I have introduced some acetone into the cracks and clamped them up hoping that it will re-bond, meanwhile the next pair are printing which should finish about 4:30 this afternoon - only two more sets after that !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: djc on May 14, 2020, 03:47:14 AM
I need substantial clamps for where the four pipes leave / enter the chiller unit and have hoses dangling on them - no easily available plumbing type clips are heavy enough duty.

What you have drawn looks remarkably similar to the clamps used for hydraulic hoses on excavators, hiabs and cherry pickers.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 14, 2020, 04:08:28 AM
Yes that's what I based it on - I have some for smaller hydraulic pipes on my JCB but not that size.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 14, 2020, 12:17:51 PM
So I managed to print a second pair of pipe clamps in ABS - these ones have to be raised 60 mm on stand-offs to clear the first pipe, but the trial fit went well. Again a bit of delamination glued with acetone but should be OK.

I have a third pair printing at the moment - these are in PET-G as I'm running low on ABS. But this time I've rotated the model so that it is lying on it's back, so if there is delamination the holding screws will hold it together - I should have done it this way first time !

This pair won't be done until about 11:30 tonight so unlikely that I can set another overnight run - you never know - there may be a good film on !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 15, 2020, 03:51:48 AM
So of course I HAD to do it - I stayed up until silly O'Clock waiting for one set of clamps to finish so that I could start another set to run over night.

So (I think) that's the last of the 28 mm pipe clamps made. I'd forgotten how nicely PET-G prints, but it's a b***r to get  off the build plate !

I now need to make a little jig to drill holes to mount them, as these mount on the underside of the cross rail, and are in a place compromised by vari-focal glasses  :clap:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 15, 2020, 10:13:03 AM
For a jig I need about six inches of suitable angle iron - casting about I found a grotty rusty bit no use for anything else, so a bit was loped off the end and sand blasted to get the majority of the horror off it, and I laid out the two holes for the pipe clamps at 48 mm centres to coincide with the centre line of the heavy box profile that I made the frame from.

This allowed me quickly to drill and tap the four M8 holes for the last two  pipe clamps while standing on my head under the horizontal frame bar.

Once the clamps were fixed, I could finalise the pipe layout, but first I had to solvent weld the Grundfos pump feed from the tank, so that the position of it's output pipe was fixed. While the solvent weld glue was setting up I re-worked the fixings for the brackets that hold the electrical cabinet in place. I made up 1" wide strips with four studs tapped and soldered to co-respond with four of the holes (that were previously legion!) giving a much neater appearance

OK solvent weld now handle able, so I could fit the pump and know where it's vertical output will be, letting me finish that run of plumbing.

Nearly ready for dismantling and painting  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 15, 2020, 03:41:16 PM
A bit more work this evening and the 'Pump House is up to roof level - or is is really a barbeque  :clap:

Then the frame for the manhole cover went back having mortared in the two pipes.

It'll be ready for electrics as soon as the brickwork ca stand an SDS drill !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 16, 2020, 11:40:33 AM
Looking good! Stellar job on the cooling unit!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 16, 2020, 11:47:58 AM
The time was right today to break down the new chiller unit and give all it's bits a coat of paint. I've tried to keep 'sets' of plumbing still pushed together (although not yet soldered) to aid re-assembly.

Once it was all apart and wiped down with Xylene, I lifted the frame up high on the forklift, put some kitchen foil on the castors to mask them, and gave the underside of the frame a blow over with the Silver hammer finish paint. While that was drying I gave the reverse side of all the panels and odds and sods a coat.

Then I was able to lower the frame and push it indoors to paint the rest of it's box sections.

By the time I'd done that, the panels and odds and sods were dry enough to invert, and paint their face sides.

All together it's not come out too badly - just short of 2 litres sprayed on ! After a major clear up and a shower I can now contemplate putting it back together tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 16, 2020, 11:52:50 AM
Looking good! Stellar job on the cooling unit!
Phil

Thanks for the kind words Phil  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on May 17, 2020, 04:04:50 AM
nice work!
 And just out of curiosity how did that turpentine bees wax anti rust mixture turn out on the long run?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 17, 2020, 06:50:27 AM
Thanks Tom :thumbup:

The turps / beeswax concoction works very well on the wood working machines - a nice thin lubricant / anti-rust coat that doesn't compromise the wood surface. It does however have a tendency to solidify in my plastic hand spray bottle - I suspect that the solvents migrate out - just needs a drop more turps every now and again !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: howsitwork? on May 17, 2020, 08:16:18 AM
hmm n8ce idea Andrew

had forgotten that one. Good to see isolation has kept you busy !

Ian
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 17, 2020, 12:23:43 PM
Today's tasks - start putting it back together, and try and make a start on mounting the electrical isolator switch that prevents opening the enclosure door when 'on'.

Re-assembly was fairly straight forwards - I'd made it like Meccano with this in mind - not started on the plumbing yet.

Working out the correct location for the enclosure isolator and it's back panel DIN rail took far longer than it should but I think (hope) it's in the right place. Then I drew up an enclosure indicator panel in Autocad, cut a plastic template from it using the Laser Cutter, marked the door accordingly and cut bits out with the angle grinder.

The four temperature indicators and an LED 'Live' light will mount on a separate panel that will attach with spot welded studs.

Then it was time to paint the rear of the electrical enclosure, that got forgotten last time, and both sides of the enclosure door. I know that I've inverted the door slightly prematurely so the inside paint will be marked - ah well who can see - it's inside !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 18, 2020, 07:25:07 AM
Time to make an Indicator Sub Panel for the front of the enclosure.

I CNC plasma cut a version of the previous drawing for the template in 2 mm Zintec steel but without the mounting holes. This panel will be fixed with studs welded with my stud welder on the back.

Having filed and fettled the panel I did a couple of test stud welds to check the settings then went ahead with the real thing. After a sand blast and coat of zinc rich paint it was cooked a bit with a heat gun, and a coat of satin black sprayed on just the front face. Another cooking with the heat gun and it was ready to populate.

Firstly checking which way up the four indicators go and marking their rears I pushed them in, retained by plastic grippy ears moulded into them. Add the power indicator and we are ready to fit it.

I put the enclosure door hinges back on, mounted the door, fitted its two locking catches, and also the mains power interlock mechanism, along with the enclosure internal rear panel onto which all the components mount. (This was needed to check alignment of the power interlock)

Then at last the indicator sub panel could go on. Nothing wired up yest - I still need to mount the 16 amp 3 phase input socket on the rear.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 18, 2020, 10:23:27 AM
I thought that I might as well cut out the mounting plate for the 16 amp three phase mains input socket - when that's fitted I can wire and test as I go.

So just a 125 mm x 140 mm 6 mm plate with a few holes in it - usual thing - drawn in Autocad, cut by CNC plasma but it needs painting before fitting. Rather than rattle can black I decided to use the silver hammer finish paint as it is basically part of the frame. Not worth getting the spray gun out I thought, brush paint it. BAD MISTAKE  :bang:

What a terrible finish brush painting hammer paint gives ! I had to wipe the entire sticky mess off with Xylene, and do what I should have done in the first place - get the spray gun out.

Came out OK in the end, and to be honest using the small touch up spray gun doesn't involve too much in clear up afterwards - remember next time  :med:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 18, 2020, 02:25:55 PM
There is a knack to brush painting  hammer finish! I don't know if it applies to that particular paint, which we discussed some time ago, and I bought 5ltrs of, because I haven't used it yet, but I find that the best you can do is experiment with different amounts of thinning, depending on how thick it is as delivered, and then put it on fairly heavy in a warm room, brush it out quickly in straignt lines, then leave it alone. The more you brush it, the worse it gets!
phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 18, 2020, 03:00:31 PM
The problem that I had was the the 'hammers' were coming out far too large.

I think the best approach to brush painting this stuff is not to  :clap:

Spray for me from now on.

,
. . . I got that socket mounted  :thumbup:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 19, 2020, 11:03:26 AM
A solid day plumbing today. Theoretically just soldering up the bits that I had previously dry fitted, but lots of sealing screwed fittings, and adapting the plastic fittings to the tank.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down  :bang:

. . . still barring leaks that should be the plumbing finished when I've blanked off a 1" BSP redundant hole in the tank. Probably need to make something  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on May 19, 2020, 11:06:52 AM
A solid day plumbing today.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down  :bang

You should have marked the orientation of everything as you had it assembled before you took it all apart.,,, :lol:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 19, 2020, 11:22:49 AM
A solid day plumbing today.


I couldn't for the life of me see initially why my pre-cut bits were SO far out - it all became much clearer when I realised that I'd put the heat exchanger in upside down  :bang

You should have marked the orientation of everything as you had it assembled before you took it all apart.,,, :lol:

John, it has a blooming great arrow and UP  in large letters  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 19, 2020, 01:06:43 PM
Never throw away old brass plumbing fittings !

Looking through my odds and sods box produced a 1" BSP female to 1" compression elbow - the female bit contributed a nice 1" BSP back nut once sliced off on the lathe. Then I found a 1" BSP male to 3/4" BSP Male nipple, and a 3/4" BSP blanking cap - all assembled into a 1" blanking plug ready to go in the hole in the tank tomorrow  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on May 19, 2020, 01:17:03 PM


John, it has a blooming great arrow and UP  in large letters 
[/quote]
I heard real men don’t read instructions!
Or is that just a IKEA thing?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 19, 2020, 03:18:48 PM
The problem that I had was the the 'hammers' were coming out far too large.

I think the best approach to brush painting this stuff is not to  :clap:

Spray for me from now on.

,
. . . I got that socket mounted  :thumbup:

too large hammers eh? never had that problem before, and I must admit
 I almost always spray , but as you say, cleanup and gunwashing is a pain if you only have a bit to do!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 20, 2020, 03:30:08 PM
So having fitted that 1" BSP bung in the tank I had to turn my attention to what to do to support the 'house water' inlet and the overflow pipe. Although the plastic tank is quite  rigid I don't want pipes hanging off it unsupported. I came to the conclusion that yet another 6 mm plate was called for, suitably pierced, for fittings to run through and clamp to.

Bit of a mare measuring up precisely where the holes need to go - I ended up with three iterations of plastic templates before I was satisfied. Straight to spraying this time, no messing about with brushes  :clap:

Having  done that I turned my attention to a  bit of wiring. I wanted to get the thermometers at least, wired up. I've run three phase to the overload trip, and a single phase feed to the low current breaker feeding the 12 volt power supply for the thermometers. I've temporarily connected a single phase input for testing, so the thermometers are now powered up, but their sensors are still just dangling in the electrical enclosure. The 12 volt 'Power On' indicator proved to be a useful commoning point for the four displays.

While I was doing this, Andy arrived and started concreting in the surround to the manhole cover, and the slot through the path where we ran trunking under the re-bar. He has cast the 'roof' for the pump house off site, but it's still too green to move - scheduled for Friday evening.

Hope to get the pump electrics connected tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on May 21, 2020, 04:41:27 AM
Just a thought Andrew, have you been able to test the generator under the expected load conditions?
You are plowing on with the other parts of the project but it would be a shame if after all this work and dedication that the project failed due to a defective power source.

I'm sure that with your normal thoroughness you have covered this but I just wondered.

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on May 21, 2020, 04:44:30 AM
He'll  just have to rebuild that too...

-Russ
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 21, 2020, 08:03:45 AM
I've only been able to load the generator up to 16 KVA and it didn't even notice that it was loaded !

Yes that IS one of the imponderables, also I don't know that the big blue furnace driver will work at high power either as it's only done low power 'pings' recently.

These things are like skittles, you need to keep knocking them down one by one as they crop up :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 21, 2020, 12:23:45 PM
Today I completed the wiring in the Electrical Enclosure - apart from running the thermistors for the temperature indicators to their relevant pipe on the heat exchanger where they will be Ty-Wrapped  with a bit of thermal compound for good contact. But I don't want to do that until I've leak tested and proved the plumbing.

Also got the SWA cable run to the pump house and wired giving a pair of 13 amp sockets - one for the pump and the other probably for trace heating to prevent freezing.

A temporary roof comprising a pig herding board will have to suffice until tomorrow night when Andy brings the slab he has cast.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 22, 2020, 09:51:42 AM
First thing this morning I finalised all the plumbing for the house water input, tank overflow, and the flow and return to the furnace including the end terminations on the rubber hose that joins the chiller to the furnace driver. Fittings are sealed with Loctite 542 that is handle-able in 15 minutes but really needs 24 hours for a full cure.

So now the unit is functionally completed (it may get some mesh panels at some time) but it needs leak testing - due to the Loctite 542 this will have to be tomorrow.

I turned my attention to outside works. A trench is needed through the goose field to take the flow and return between the foundry and the bore hole. There was a fence running parallel to the foundry that pre-dates it's building (where it is was just a fence enclosed yard outside the workshop) - fence no longer needed and posts rather rotten so it had to be grubbed out first, along with an Alder tree that had self seeded behind it.

Then I scraped the ground clear of various piles of earth and weeds that had accumulated followed by digging a trench for the pipes going through the gate opening and running practically to the south end of the foundry. This means that there is only about 15-20 foot of trench to dig to complete the run, but will have to been done by hand as there is no room to get the JCB803 in there.

. . . .getting there . . .  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 23, 2020, 10:28:02 AM
This morning having linked both sides of the chiller into one continuous loop for testing I filled the new chiller tank and started leak tests - all good EXCEPT for the plastic feed from the tank to the Grundfos pump that has a slight drip. I'm not entirely surprised as I wasn't particularly satisfied with this pipe run - it is of course rather a pain to sort out. I did try a crude bandage of self amalgamating tape squashed with a Jubilee clip as a temporary fix but it wasn't having it. Of course when the pump is running, as it's under suction, it doesn't leak, but I'll have to re-work it somehow.

But the good news is that all the rest of the pipework is sound and good to go  :thumbup:

Then I started on the pump from the bore hole, making up a weighted suction hose using one of those house bricks that has holes rather than a frog, as this allows it to be securely tied to a safety rope. Weighted as otherwise it curls all over the place.

Once this was secured on the pump and lowered down the well, it was a case of a few alterations to the existing 25 mm MDPE plumbing feeding the horticultural area, and running 32 mm MDPE from the pump to a Tee junction feeding this modified pipework. The 32 mm will continue in the trenches to the foundry but currently just goes to a stop cock for testing.

The pump control unit has a male 1" BSP plastic spigot at the bottom for feed from the pump, and at the top for flow out. Both gave horrendous problems getting a good seal, having to be re-made several times - I loath plastic screwed fittings! But we got there in the end.

The final flow rate, although I've not yet measured it, seems excellent.



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 23, 2020, 10:38:55 AM
That's really coming together!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 23, 2020, 01:19:13 PM
Watch that suction pipe, the corrugations caused me no end of trouble to get it sealed! It was stopping the pump lifting on my rainwater recycling rig, and I eventually use ptfe and two jubilee clips to get it to seal! It was leaking where it joined the foot valve, and allowing the pipe to drain out!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 23, 2020, 03:16:34 PM
Touch wood ATM that bit is OK  (the inner wall is plain - corrugations only on the outside) but I've just noticed a weep from the upper 1" BSP plastic connector  :bang:


. . . .more re-work needed

But I think that I've found a simple solution to the 'tank to Grundfos' pipe leak, hopefully suitable bits ordered

And again , hopefully, the rest of the trench is being dug tomorrow :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 26, 2020, 05:31:07 AM
First thing yesterday I finished hand digging the pipe trench, and have the blisters to prove it :clap: This first part of the trench is quite shallow, so once a few inches of soil are covering the cable and pipes I'm putting old roofing tiles topped with warning tape then fully back filling

Then having identified that I still had some 4 core 6 mm SWA cable (53 amp rated) left over from the Tractor Shed build, unrolled it (on grass to avoid scratching the sheath) and found that there was 15 metres on the reel.

Careful measurement of the only possible route from the main distribution board to a suitable spot in the foundry for a sub-panel showed that it was tight but just about achievable length wise - on this basis I ordered up a 4 way 3 phase panel and started drilling the necessary holes.

Both the main workshop and the foundry wall that needed drilling have changed their form several times over the years - the main shop is timber feather edge clad, but on the welding shop side I've built a fire stop from 100 mm block-work, and on the workshop side it's been foam insulation sprayed and lined with 18 mm OSB board, so the aggregate thickness is quite considerable and fun to drill holes in. Entering the Foundry, the only route was through the 6 mm web of an RSJ up in a tight corner, the other side of which was again ultimately feather edge board with other layers between.

In all a fun time but the cable got there in the end - length limitations mean I can't put the sub panel quite where I wanted, but it'll be OK. From this panel will radiate feeds to two 16 amp commando  sockets (for new cooler and pottery kiln), several twin 13A sockets and the lighting circuit.

Now I need to cut a load of box section to weld into the structure of the foundry to support the sub-panel sockets and a water panel for flow and return from the bore hole.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on May 26, 2020, 10:01:23 AM
I have to say, this is quite an amazing project.... I really hope the thing works for you after all this effort!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 26, 2020, 11:35:20 AM
Well Ade, it would be rather nice if it does :clap:

And if it doesn’t , well there’s another challenge to tackle.

As I sit here typing a friend is putting sealant dope on the corrugated cement roof as it was laid to too shallow a pitch and water tracks up the valleys when it rains and leaks in at the sheet overlaps. Seems to be pretty good stuff with 10 mm fibres to bridge gaps. At the price it should be fantastic 😀
 
It’s called Cromapol and has some pretty good reviews
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 26, 2020, 03:48:00 PM
Chromapol is the dogs whatsits Andrew, It is expensive, but cannot be beaten for roof repairs, especially flat and built up felt roofs. Sweep the water off and apply it straight to the wet roof!!! as it settles into the leak the water comes up through the chromapol, I did not believe it till I used it.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on May 26, 2020, 05:33:35 PM
Only if you're having problems with your hair, Phil  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 26, 2020, 05:42:45 PM
Glad to hear that Phil, as Terry has completed all the joints, and will return to give it all a full coat with, again, emphasis on the joints, but covering everything, tomorrow. It was nice and warm today so it went on very nicely.

Meanwhile I built up the new 3 phase sub-panel ready for installation, and stripped the paint off some more 50 mm box section ready for mountings for the panel, water panel, and various sockets.

Later we laid the flow and return pipes between the bore hole, pump house and foundry. The return goes to the over flow pipe under the man hole cover via a 90 degree bend - no doubt this will confuse someone in the future! But the flow is at the moment not yet connected to the pump. Their ends now emerge in the foundry waiting for me to make up their termination panel.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 27, 2020, 06:26:05 AM
Sorry seadog, all I heard was the whooshing noise as that went straight over my head, although I do have to wear one of my (daughters old tights) hairnets when I use Chromapol....there have been messy disasters!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 27, 2020, 10:30:42 AM
Today's task: form supports for the electricity sub-panel, water panel and 3 phase sockets. I cut six suitable lengths of the 50 mm box section that I cleaned up yesterday, welded a pair for the sub-panel, but before I could use the grinder or welder near the flow and return water pipes they needed protecting from sparks.

Simple solution (I thought!) slip a bit of scaffold tube over them. It wasn't until I was welding that the weight of the scaffold tube managed to kink the MDPE pipe  :bang: It's no big deal - both these pipes emanate from 90 degree elbows at sub-ground level so are quite short - I'll just replace them as I'm not short of 32 mm MDPE pipe. They'd probably be fine having been unkinked, but silly to take the risk.

Then I drilled and tapped for the electricity sub-panel and wired in both ends of it's feed. Irritatingly I found that the brand new 30 mA RCD trip was faulty. It doesn't trip when it's test button is pressed - replacement on the way tomorrow 

 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 27, 2020, 04:13:56 PM
"I found that the brand new 30 mA RCD trip was faulty. It doesn't trip when it's test button is pressed"

Doesn't tend to boost ones confidence in modern electrical equipment does it? Probably made in China. I wonder if it would have tripped in fault conditions, given that the test button simulates a fault, one would suspect not, meaning of course that the faulty circuit would have no upstream protection except the 100amp cutout fuse. God bless the IET, they really know what they are doing by getting rid of those dangerous old rewirable fuses that always fail safe!

Under the old IEE regs, written by engineers, not equipment manufacturers,

"No electromechanical device may be fitted to any circuit as a SOLE means of protection against fault currents".

Rant mode to "OFF"
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 27, 2020, 04:33:16 PM
It's a Wylex, as is the sub-board I'm fitting, so a reputable make.

But amusingly, when you fit an RCD as opposed to just an isolator in the Wylex NH series  3 phase boxes, you have to buy a little 'kit' with extra links and DIN rail to mount it. Included is a clear plastic cover for these links with a label pre-attached saying something like 'disconnect supply before removing' BUT THEY STICK THE LABEL ON UPSIDE DOWN  :clap:

I've fitted several of these boards with the kits - the screws holding the insulation clear cover are asymmetrical so it can only go one way, but the first time I found it, it had me puzzled for quite a time trying to fit it. Now I just peel the label and stick it back the right way up   :ddb:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on May 27, 2020, 05:08:01 PM
Sorry seadog, all I heard was the whooshing noise as that went straight over my head, although I do have to wear one of my (daughters old tights) hairnets when I use Chromapol....there have been messy disasters!
Phil

http://dir.cosmeticsandtoiletries.com/detail/tradeName.html?id=22073


Rather than https://www.cromarbuildingproducts.com/products/cromapol/
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 28, 2020, 05:12:36 AM
Firstly this morning I replaced the risers of the flow and return pipes that got kinked yesterday, and removed the faulty RCD for when the replacement arrives.

On the bench, pressing the RCD 'Test' button introduced no leakage current - it's supposed to put a resistor from the lives to neutral to introduce and imbalance and trip. To prove my theory I did the same test with (admittedly a single phase) spare RCD and could measure the resistance when the button was pressed. OK it's definitely faulty !

Then I drew up panels to mount the flow and return  water pipe terminations on the verticals that I've welded to the building structure and cut them on the CNC plasma table and trial assembled the plumbing that turns them through 180 degrees and gives a barb fitting for more flexible hose leading to the chiller itself. The hex nipple in between the two elbows doesn't give enough separation, but the running nipples that I have on order haven't yet arrived.

. . . now off to paint the panels !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 28, 2020, 07:52:43 AM
OK panels painted, now twiddling thumbs waiting for deliveries !

. . .  and while typing, the coupler for the chiller pump feed pipe, and the full length 1" BSP socket to fix the bore hole pump have been delivered  :clap:



So I set about cutting the leaking Grundfos feed pipe and solvent welding an extension on to allow me to install the universal coupling - but the solvent weld will have to dry first.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 28, 2020, 04:54:26 PM
Sorry seadog, all I heard was the whooshing noise as that went straight over my head, although I do have to wear one of my (daughters old tights) hairnets when I use Chromapol....there have been messy disasters!
Phil

http://dir.cosmeticsandtoiletries.com/detail/tradeName.html?id=22073


Rather than https://www.cromarbuildingproducts.com/products/cromapol/

Now I understand!! LOL, the new girl at the hairdressers could get the push if she mistook one for the other!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on May 28, 2020, 05:56:34 PM
Definitely, Phil. It'd make a right mess of your dreads  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 29, 2020, 08:02:19 AM
Last night I  wired up a 'mini-ring main' to give me some local power sockets, and this morning fitted the 'universal coupler' to the Grundfos feed pump, hopefully eliminating that tiny drip.

I also re-worked the bore hole pump output fitting that had developed a tiny weep - I love rigid plastic threads - NOT!

Having tested that the chiller pump pipework was now sound I fixed the temperature sensors to the appropriate pipes, using thermal compound and Ty-Wraps. Sensor leads not long enough for nicely run cables so a bit of a spiders web.

Having now labelled the temperature display I think that this new chiller is now finished - hopefully !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on May 29, 2020, 08:28:22 AM
Great! So now you can chill out! Looking good!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 29, 2020, 01:06:32 PM
Very good Matthew  :clap:

So the longer running nipple was delivered at lunch time so I was able to dry assemble the components of the bore hole flow and return panel, offer them up to the verticals that I welded on the other day, and drill and tap the mounting holes.

As I was at it I also mounted the panel for the 16 amp three phase socket at a high level to be away from any water leaks, although the 3 phase sockets still haven't been delivered.

Once I was sure that everything was suitably accessible for tightening up, I pulled it all apart and re-assembled it with Loctite  pipe sealant on all except the plastic MDPE connectors where I used thick 'gas rated' PTFE tape.

A bit of careful measurement re pipe lengths, a couple of snips, and the deed was done - panel now fixed awaiting wetting up.

I've done a bit of a re-think where the burn out kiln will be placed - needed to decide as another 16 amp 3 phase socket needed - it's now spun round 90 degrees and crossed the door way !

While all this was happening, the loctite on the bore hole pump was hopefully curing but hadn't had the full time intended, but as a certain person wanted to water her poly tunnel I took the risk and turned things back on - phew no leaks (yet!)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 30, 2020, 05:19:53 AM
Having set over night the Loctite pipe seal on the water panel 'should' now be Ok so I connected the borehole pump output initially via the existing temporary stop cock 'just in case' and did a leak test - all seems good.  So pipe cut to length and connected directly and again tested - all good so far.

And the really good news is that the troublesome joint on the pump controller output that I re-sealed yesterday has so far NOT leaked despite the Loctite 542 being prematurely stressed  :thumbup:

. . .so the flow and return for the new chiller are up and running in the foundry, just awaiting the 16 amp three phase sockets and the flexible umbilical water pipes (water panel to machine)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on May 30, 2020, 06:27:21 AM
You'll be melting by mid summer...

Sent from my SM-G965F using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 30, 2020, 08:59:44 AM
Definitely, Phil. It'd make a right mess of your dreads  :clap:

It DID!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 30, 2020, 09:06:07 AM
Andrew, re the kiln position, could you put one bay of shelving where the kiln is and move the kiln to where the shelving was?
Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 30, 2020, 09:51:22 AM
Phil, a very constructive comment and you are correct that there would be a far better place for the kiln (nearer the distribution box, and backing onto a steel fire door rather than timber cladding. But unfortunately, being 40 inches deep (shelves are 15 inches deep) it completely blocks access to the back door.

Where it is, is rather 'out on a limb'. That whole side of the foundry is a pain as there is a huge sliding fire door floor to roof taking up most of the length of the wall and precluding mounting sockets etc.

Putting the shelves where the kiln is and shunting the foundry bench nearer the rear wall and putting the kiln next to it is a possibility but still has the problem of no where for it's socket and it sticking out a long way  :bang:

When I built the kitchen in my first house (back in 1973!!!) I made a model out of (now banned) polystyrene ceiling tiles - perhaps I should find some ceiling tiles :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on May 30, 2020, 09:59:35 AM
Ah I see, Buggr!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 30, 2020, 10:35:22 AM
Phil, let it not be said that you are without influence - you've got me shifting the furniture AGAIN  :bugeye:

By spinning the Kiln 90 degrees it only protrudes 32 inches when on the end of the second foundry bench and you can still just get at the rear door. The socket problem is overcomable, as although it backs (sides actually!) onto the sliding door, there is an RSJ above that I should be able to fix a socket to. Trailing cables aren't possible as it's between two doorways)

I'll sleep on it, but probably this is a better layout so thank you for prompting me to get the pallet truck out yet again  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on May 31, 2020, 12:37:13 PM
Time to think about making a door for the 'pump house'. Needs to be something a bit more durable than B&Q pine but I'm clean out of recycled oak or any other hardwoods. No, hang on, there's an old ledged and braced  plank door in the stable keeping the rain off the straw pile that we replaced when we did a refurbish on the house some years ago - will it dismantle and provide stock ?

(Picture of it in situ before we virtually demolished the house in 2012 !)

Turns out that it was entirely screwed together making dismantling relatively easy - planks are about eight inches wide but have 1/2" grooves with inserted tongues to hold them together so you lose an inch.

Bottom edge of the door was rather water damaged from neglect but it has provided enough stock to make the new and much smaller door. I also found some chunky window sill material of odd tropical hardwood that was probably removed at the same time from which I milled a pair of  3" x 2" door jambs.

I milled the planks down to five inches so five planks for an approximately 25 inch wide door. I should have passed them through the planer thicknesser at this stage, but it didn't occur to me until I'd cut them to approximate lengths. Never mind - two passes to remove the varnish and glue. Pity it doesn't remove the screw holes as well!

So far I've got the timber and the idea but not yet fixed them together as other things crop up to distract me.

I'm thinking not to hinge this door but to make it a removable panel - possibly retained by rare earth magnets but not decided yet.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 01, 2020, 06:57:16 AM
This morning I cut the pump house door jambs and temporarily mounted them to allow me to measure the door's final size. They will come off for varnishing in due course.

Now having the door final size I trimmed the planks to give me about 1/4" to plane to final size, glued and mounted them up in a pair of sash cramps and fitted the ledges to hold them flat.

I'll give the glue over night to set before any more work on them.

Meanwhile the 16 amp 3 phase sockets have arrived so I suppose that that's work for this afternoon sorted !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 01, 2020, 12:41:35 PM
I decided to give the door jambs a coat of varnish so that it can dry over night and be re-fitted in the morning. I was just starting when a desperate neighbour arrived needing his 'digging spoons' welded as one spade had completely broken off.

This delayed starting the wiring but I did get the 16 amp 3 phase socket for the water chiller fixed, wired in and tested - one more to do for the kiln.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 02, 2020, 10:24:08 AM
Today's job : Mount the 16 amp 3 phase socket for the burn out kiln. To mount it on the RSJ above called for a back plate and angle, with holes drilled up into the RSJ to bolt it to.

Simple drawing in Autocad incorporating the 5 degree slope of the RSJ to keep the socket level. However when I imported it into Sheetcam I found that I had no tools defined :bang:

Yesterday, fed up with Microsoft falsely accusing me of running a hooky operating system, I had changed over to a standby PC that I had previously loaded with all the legacy software that I need to run as 32 bit Win 7 but had obviously forgotten to bring Sheetcam's tool set over. This system I had managed to turn off automatic Windows updates BEFORE Microsoft 'upgraded' to their spoiler version that is determined to stop you using Windows 7. (I have to).

I eventually resorted to bringing up the old system and exporting the tool file but a pain - thanks Microsoft  :(

So at last I managed to plasma cut the backing plate, cut and drill a suitable bit of 50 mm heavy angle iron, clean them up and spray them. This time I remembered to spray the manhole cover lifting keys that I made - they will be living in the 'pump house' so I wanted to at least make a token gesture to keeping them free of rust! I've intended to spray them for weeks and each time the gun has been full I've forgotten. Holes drilled and a pair of 4" No 12 screws put in the back wall to keep them safe :thumbup:

While I was doing this Clive (our 1/2 a day a week gardener) made a splendid job of back filling the shallow trench and seeding the nice tilth that he produced. The pipes were separated, fine earth put between them and about 2" over, followed by continuous roofing tiles to guard against spades and forks, topped with a yellow 'cables below' hazard tape, and earth to surface level.

By this time my paint had dried enough for the backing plate, angle and socket to be mounted - but this time I pre-wired the socket as the last one was a neck cricking nightmare! SWA cable clipped to the RSJ and run to the sub-main distribution box, wired in and tested - All OK and the kiln got a brief warming for the first time in months

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 03, 2020, 07:11:46 AM
A series of little catch up jobs this morning as rain is threatened over the next few days:

Firstly I fitted pipe clips to the outside of the foundry and fixed the flow and return cooling pipes in place.

Then I bored a hole in the wall for the new Chiller tank overflow and fitted a suitable right angle of 40 mm waste pipe - still short of a pipe clip - giving an up stand for the overflow to go into.

Then I back filled the main pipe trench - again a few inches of earth followed by a warning tape followed by the rest of the back fill. The tape warns of cables below but I expect it'll stop rampant digger drivers in the future despite it being water below  :clap:

Then the man hole frame and cover got a good greasing before being put in place after what seems ages  of a temporary cover.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on June 03, 2020, 08:16:53 AM
I am really looking forward to seeing this installation!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 03, 2020, 08:42:52 AM
And so you shall Matthew - I presume that viruses permitting you will be over in December?

After lunch the small oak door for the pump house got it's first offering up and planing to the wedge shape it needs to be (1/4" discrepancy in width top to bottom in the opening!) But then the heavens opened up and stopped outside work.

Quite a deluge, and (SO FAR!) the roof sealing seems (seams!!) to be working in the main span of the roof where the joints were leaking. There is still a leak where the two buildings join and I think perhaps a fillet of cement followed by the sealant is gong to be about the only way to seal it.

To be honest I'm not entirely surprised, but now I have it on video I can work out exactly where it's coming in (and conveniently dripping on the old electrics  :bugeye: )


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on June 03, 2020, 09:46:35 AM
And so you shall Matthew - I presume that viruses permitting you will be over in December?

Viruses permitting!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 03, 2020, 10:58:10 AM
Still raining here so no more roof investigations or door fitting. But I thought at least I can stop up the 'blemishes' in the pump house door with "Brumers Stopping"  ready for varnishing, if only I can find my little tin . . .well I couldn't  :bang:

Buy on line ? - silly money and long delivery - ruled that one out.

OK you've got waterproof wood glue and lots of fine oak sanding dust having faired the door planks - make some stopping ! I have to say that 'Andrews Stopping' came out much the same consistency as the real thing, and the colour certainly will be  better match as it's the same wood!

No doubt it will shrink so I left it proud for later sanding down - probably tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 04, 2020, 08:44:23 AM
Rain threatening again today, so I shot out first thing and measured up and planed the Pump House Door to final size, and made a pair of toggles to retain it. Then I sanded it down and gave it it's first coat of varnish along with the toggles.

Then I pumped out the water from the chiller tank, and removed all the temporary testing loops of flexible pipe, and trundled it into the foundry to it's final location.

The 10 metre coil of 25 mm bore reinforced PVC hose and Jubilee clips arrived yesterday, so I was able to connect up the umbilicals from the wall to the unit for the flow and returns from the bore hole leaving I hope enough slack to pull the unit forward for servicing.

Then it was time to fill the tank with glycol solution. I have two drums of diluted glycol - one diluted to -3 degree Centigrade protection, and the other to -30 degrees centigrade. I moved the pallet with the drums into the foundry and pumped directly into the tank, first half filling with the -3 solution, then topping up with the -30 solution, which according to my Brix meter gives protection to -8.5 degrees C. This will all change when the furnace and driver unit are attached as they contain quite a volume of coolant.

Moving the Furnace Driver into place, although the rubber pipes that connect it to the chiller are just long enough I've decided to replace them. they are rather soft and these were the ones that the rats chewed the end off. I've ordered another 10 metre coil of 25 mm bore PVC reinforced hose - I hope that it's happy carrying glycol solution.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 04, 2020, 12:44:12 PM
So time to sort out the new home for the generator after all these months.

The stable, where it is next going, was stacked with crates of fire wood, IBCs, Pig Weighing Crates, Wheelie Bins and all the paraphernalia that accumulates and it all had to come out. Some could stand a bit of rain and were put in the inner farm yard, but all the wood was transferred to the tractor shed having moved the generator into the yard and covered it in tarpaulins for the night.

I have four very heavy duty wheels and tyres (rated 1700 kg each at 15 kph) whose hub bearings have completely rusted solid. Knocking the races out has left a bore a bit bigger than a scaffold pole, so the plan is to jack the generator up, slide poles through holes in the RSJs that form its base, and put the wheels on and roll it into place. This is needed as I can't approach the final resting place with the fork lift at the right angle so it needs manhandling the length of the stable over very rough concrete.

Meanwhile the fork lift has a new temporary garage !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 04, 2020, 01:19:52 PM
I feel a woodshed build approaching  :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 04, 2020, 01:30:20 PM
Already got one Graham, up by the house, and it's empty, but there is a dead tree close to it that needs felling, logging, splitting and stacking so that it is deepest in / last to be used, before some of those Apple bins  of logs get tractored down to the house and stacked in it.

. . . any volunteers ?

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 04, 2020, 03:37:01 PM
More than happy to destroy a tree. I need to do a bit of manual labour.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 05, 2020, 08:59:31 AM
First job of the day, put another and hopefully final coat of varnish on the pump house door and door frame. This should now be finished bar a handle to pull it open, and the making of a couple of plastic foot like spacers to stop it sitting on the (potentially wet) lower slab and rotting.

Then the big  move - pulled the tarpaulin off the generator, moved it so that it was roughly aligned with where it need moving, put an axle and two wheels on the front, and sat the back on a pallet. The theory being that I could push it with the fork lift to pretty well where it was meant to be.

Well theory and practice often differ  :clap: As the floor of the stable slopes I couldn't stop the front end gradually running off course and going down hill. An 8 ton block and tackle attached to a front chassis member  at one end, and a support RSJ of the stable at the other turned it's head in the right direction. Then the application of a pallet jack to the front allowed a friend to steer it while I pushed with the forklift.

Eventually we got it deep enough in to the stable and close enough to the wall that I was just able to get the forklift under the generator at 90 degrees to the side, pick it up and finesse it's positioning. Getting the fork lift back out was fun as it's a relatively narrow space reduced by the width of the generator, the length of the forks and of course the length of the forklift itself. I think it took about six back and forth jiggles with clearances measured in fractions of inches  :bugeye:

Generator placed and a start performed - it still works  :thumbup: Then started a considerable amount of putting away all that had been displaced. I gained some space by double stacking some pallets in the tractor shed but the stable isn't tall enough for that trick!

Main generator cable unrolled between the big blue Induction Furnace Driver and the generator, and yes, it's long enough so that's another unknown ticked off.

Now I need to sort out the generator exhaust to the outside world - it very quickly fogs up the stable despite 'Yorkshire Boarding' (6 inch planks spaced one inch apart) and fully open drive through doors either end.!

. . . but we ARE getting there  :thumbup: :thumbup: :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on June 05, 2020, 09:30:23 AM
Looking good.
Not sure how your forks are secured on the Hyster, but when I have found myself in a 'sticky' situation, I just slide the forks off their backplate,
move the machine, drag the forks out from whence they are stuck, then pop them back on again. Can save a lot of 'tooing and froing'.
Not sure if that is possible with your machine. HTH.
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 05, 2020, 09:37:26 AM
No Pete, my frame is pegged to stop the forks sliding off. I'm sure with a bit of work that it's possible - but not that easy (by design)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on June 05, 2020, 12:33:47 PM
No Pete, my frame is pegged to stop the forks sliding off. I'm sure with a bit of work that it's possible - but not that easy (by design)
Mine wasn't easy until I took the safety bolts out. :bugeye: Having said that, it's usually easier to just drop the complete backplate/fork assembly off the machine with a couple of small levers.
As your machine is a specific forklift, I did not think the latter facility would be available to you, but that the former might.
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 06, 2020, 11:12:30 AM
So varnish dry, PTFE spacers fitted and door finally in place. Why PTFE - 'cos I happened to have a stick of the right diameter sitting by the lathe !

With the door on it was now worth making and fitting the anti-vermin shield round the cable and pipe entries in the Pumphouse floor. I drew it up in Autocad and had intended to cut a trial in plastic using the Laser Cutter, but when I turned it on, on performing it's initialisation homing sequence it's ignoring one of the sensors and crashing into the end stop. They are hall effect sensors and in fact waving a bit of metal at the 'faulty' one it lit up so possibly a broken wire - something to investigate  :scratch:

So never mind - cut it in metal. Actually it fitted rather nicely - three bits needed to be able to get it in place, and rare earth magnets join them pretty effectively.

But having cut the steel on the CNC Plasma Table why is the welding shop full of fumes? The automatic fan hadn't turned on as it should but works happily if manually turned on. Something else to investigate.

OK next job, extend the generator exhaust to a height that it will clear the feed bin lids when they are open, and make up the length to take it outdoors. It's 2 1/2" BSP heavy walled steam pipe. I had about 50" of it and a length of flexible exhaust left over from when I got the generator. Careful measurement told me that by lopping 14" of the pipe and threading both ends I could get the height right and there would still be enough to reach outside if I used a bit of the flexy that already had a threaded stub welded in one end.

So how to thread 2 1/2" BSP - my threading gear stops at 2". No alternative really than single point threading it on the lathe using a fixed steady.

Slight snag - no 55 degree external threading tips - got internals but that's no use. Hang it it's not a nuclear submarine it's an exhaust - use a 60 degree tip and wing it  :clap:

Slight adjustment to threading depth to get a reasonable fit, and a bit of crest rounding with a file and my 'thread gauge' (a malleable iron elbow) was a tolerable fit. Time to assemble it all.

Firstly I bored a five inch hole through a six inch Yorkshire Board in the stable wall which should be enough clearance to keep the hot exhaust off the timber. I need to find some insulating material to support where the pipe passes through the timber.

Then all was screwed together and a test run performed - all OK

Incidentally I went to fire the generator up last night and there was a very loud bang and a spurt of flame from the side of the generator. Scary at the time, but it proved to be the cheap Chinese battery isolator switch had failed in a spectacular way spewing it's contacts in molten form across the top of the battery. Needless to say I took the switch out of circuit!






Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 07, 2020, 01:20:35 PM
WE HAVE A WORKING INDUCTION FURNACE !

What a day  :ddb:

I started by making a bracket to hold the generator exhaust pipe central in the hole in the Yorkshire Boarding to try and avoid fires.

Then, as the new roll of 1" PVC reinforced pipe had been delivered yesterday set to reworking the hoses that run from the new chiller to the furnace driver box. All fairly straight forward, jubilee clips onto hose barbs, though I have double clipped all ends just in case.

At this point I was able to connect the chiller to the furnace driver which was already connected to the furnace body (where the crucible is) and test for leaks.

All was well except for a slight drip from one of the 1-1/2" unions that the driver unit uses. This was eventually cured once I'd found an ancient tin of Boss White that was still workable, the first one being solid !

So now dare I try powering up?

Cables run out - by heck they are HEAVY! Generator started, furnace driver switched on and it immediately tripped it's main breaker - not good, but knowing that it had been OK on genuine mains 3 phase at low power it pointed to a generator or cable fault.

Measuring the input to the Furnace driver voltages were all over the place - 250 (ish) between two phases 415 or so between others. At the generator end all was well with the correct 415 between phases.

It MUST be the cables, but I'd buzzed them through for continuity when I dug them out recently and they were OK. Very odd  :scratch:

Major engineering feat opening up cable ends (plugs / sockets) and to my absolute HORROR found Live 1 and Earth interchanged on one of the sockets. I'd hunted for the core to test with a meter probe but not paid attention to what connected to what. Now I know for certain that this cable (these cables) had been working fine before I moved from Bromley, so how the heck had two wires changed place in the mean time.

Then it dawned on me. Shortly after we arrived here EDF wanted to recable their overhead wires into 'bunched cables' and I'd had my previous Agrekko  generator running for a couple of days while they were on site. A week later they'd rung me up and begged the loan of the generator as it was towable, to keep a local village powered up as a care home couldn't be without power. I remember saying that I had the heavy cables but no socket for the other end for them to use, and getting the reply 'No problem we'll remove the cable end and put it back afterwards.

99% certain that the EDF contractor had interchanged those two wires - hideously dangerous  :bugeye:

OK now we have proper 415 volt three phase  :clap:

Does the furnace driver work - no  :bang: I got the same error that I had had a few weeks back that the water flow wasn't being detected. OK link the error out and press on. Unit goes 'Pret' (ready) and pings the furnace body determining it's resonant frequency.

A length of 1/2" steel black bar in the crucible and try proper heat. Now I daren't actually melt anything yet as I have no compressed air to invert the furnace and dump the melt out, so lowish power test.

Good signs - smoke off the residual oils on the bar as it heated then a nice dull red glow - I wound the power up to 20 kW just to get it a bit brighter and decided that it was probably as well to quit while I was ahead.

The temperatures on the water chiller all looked sensible but in my excitement I failed to take pictures.

. . . in all a good day and a big relief  - now for . .  :beer:



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: pycoed on June 07, 2020, 02:20:07 PM
Bravo :clap: :beer: - but, but, but,what are we to look forward to next? How about major hydraulic repair on the tractor or JCB? (Just finished minor hydraulic repair on mine)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on June 07, 2020, 02:44:05 PM
14 pages thread and on #340 post it is alive! Anotoher great mega project. Even writeup is major work, not to mention the several units fixed, checked, moved overhauled during the process. I am very impressed. Showed the picture of the generator to my wife and said that we need one. She said "sure" and then I told what size it is....she was ready to dial for a professional help.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 07, 2020, 05:25:46 PM
Fantastic news Andrew. Well done, again   :bow:   :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on June 07, 2020, 05:55:07 PM
Glad to see it working! ....... So what are you going to cast?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on June 07, 2020, 08:12:55 PM
Well done mate! Soon be time to break out the moulding sand and the flasks! I don't remember whether you were using green sand or petrobond?

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on June 08, 2020, 01:12:03 AM
Good show!

Just make sure you keep your ring finger out of there when it's switched on   :D :D :D
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 08, 2020, 11:20:51 AM
Thanks for the comments chaps :thumbup:

It's a huge relief to find that the Furnace Driver is fundamentally working still after all these years lying dormant. After all the excitement yesterday I readily admit that today I feel exhausted, so trying to scale back on activity just wanted to do a bit of 'first fix' for the compressed air supply, ready for the bits that should arrive tomorrow.

First I had to weld two more vertical box sections to give  something to fix the panel to, and I decided to mount a twin 13 amp socket as well as the air termination. (The location is well down towards the large roller shutter and a socket will be handy for work outside)

In the end I did do the wiring for the socket - this will eventually be part of a ring main, but currently is wired as a spur as the next socket round the ring main will be where that roof leak still hasn't been cured so cannot be completed.

. . . time to put my feet up  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 09, 2020, 11:06:37 AM
Rather late in the day my plumbing bits arrived, so compressed air has now reached the foundry  :clap:

Or rather it hasn't yet as I'll leave the pipe thread sealant on the stainless and brass screwed fitting overnight to go off properly before opening the isolator valve.

. . . getting there . .

I'm now beginning to look at the cosmetics of the CFEI furnace driver where it has suffered significant surface rust over the years but I think it is recoverable if not left too long. Can't be a proper 'strip and blast' job as too much to dismantle - some panels and doors can be removed, and the rest will have to be a careful masking job.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 10, 2020, 06:14:40 AM
Now that I have compressed air plumbed to the foundry I am able to work on the two 'furnace bodies' that I have (an "inverter" and a "tilter" )

Today it was the turn of the "Raydyne Tilter" - I had re-built this body years ago (2006) replacing the crucible with one from a batch that I had had made behind the old Iron Curtain (as they weren't available as stock items). I also modified the control system from purely pneumatic to 'air over oil' at the suggestion of the late John Stevenson as just using air it was difficult to control 'bounce' as it went up and down. I built in a differential 'up' and down' system using one way valves and a flow rate control for each direction.

The oil reservoir is a cut down carbon dioxide cylinder and most of the plumbing was domestic water fittings as that was all I had access to.

A quick inspection showed that a 15 mm stainless pipe had been whacked and kinked but probably still worked and a few brass pipe clips had sheered off. So I connected it up to the new compressed air system and tried the 'up /down' lever - it was bent but judicious bending got it moving however apart from a bit of hissing nothing happened  :bang:

Checking the reservoir - yes there was oil. Slackening off fittings - yes oil from the 'up' outlet but nothing at the cylinder  :scratch:

As I turned away there was a big 'POP', and turning back oil was spewing out towards the Oxy-Acetylene store at a great rate of knots - the flexible hose to the cylinder has burst off it's crimp. Over the years the hose has adversely reacted to the hydraulic oil and was blocked - after all it was only designed for water!

A quick assessment gave me a count of six flexible hoses - replace one replace ALL I think, and I was about to order them up when it struck me - I now have proper hydraulic pipe and fittings with the crimper to go with it - make your own. So I will !

I'll do a bit of re-design to eliminate as much as possible of the water plumbing and do it all in 1/4" BSP hose and fittings as it's rather more flexible than 1/2" (although I have stocks of both)

(Pictures below are of the crucible and a test firing I did shortly after replacing the crucible (to dry the lining) back in 2006, NOT today but the other pictures ARE today)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on June 10, 2020, 07:56:17 AM
Andrew, I have not noticed you saying how much melt you can produce at a time.
I'm following your progress with much interest.

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 10, 2020, 11:02:52 AM
John,

It's an odd thing but I was sure that I'd replaced crucibles in both furnace bodies with new ones both of the same size, however in trying to answer your question I see that in fact the tilting one has a much larger crucible than the inverting one. I have the original box on the shelf from 2006 in which they were delivered (to my place in Bromley) as I had to order several at the time. I will have to open it up and see if in fact I ordered two sizes, or if my memory is playing up and perhaps I only replaced one  :scratch:


. . . . old age is a dreadful thing  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 10, 2020, 11:48:48 AM
Well I'm not cracking up after all, I DID replace both crucibles. I obviously bought four of each size and still have three of each size remaining.

See pictures for sizes
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 12, 2020, 02:59:34 PM
Yesterday I managed to get the cast concrete slab onto the Pump House as a roof. This has been cast with a 1"  fall from front to rear to shed the rain. Sadly I managed to chip one corner but never mind, it's no great issue.

Having the lid on allowed me to fit the 80 watt tubular heater that on it's lowest thermostat setting is supposed to be proof against frost - handily this had just been delivered so could go straight in. I knew when I ordered it that is was going to be a tight fit - it's the same length as the inner rear wall to within a millimetre and JUST fits - phew !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 12, 2020, 03:25:28 PM
Today's task was to complete the ring main in the foundry. The roof leak is still present and will be until the weather improves and we can work on it, so I took the cowards way out and re-located the final double socket out of the drip zone  :clap: This involved threading cables and fitting girder cable clips in odd inaccessible places and took longer than it should have, but come lunch time it was finished and tested, allowing me to finally close up the sub-panel and label it's various ways.

Conveniently over lunch Hermes delivered a 125 amp three phase 'free socket' that I won on eBay. I wanted this so as to be able to power up the furnace driver (at low power) off local mains for testing rather than rolling out the long heavy cables and starting the generator. I had worked on the two issues I've had preventing it going 'Pret' (ready) and wanted to prove that I'd fixed them - I had  :ddb:

So now is the time to pull everything apart for painting. The paint (hammer finish light blue) is the same paint that I sprayed the generator with, and also the electrical enclosure for the new chiller unit. Although obviously it's not an exact match for the original, it's actually not a million miles off. I will try to spray it in such a way as to form minimal hammer effect (high pressure, light coats, don't wet out surfaces fully). It's a pretty tough forgiving paint that covers many blemishes and oh boy will it have to ! (paint and thinners also arrived yesterday)

I now need to devise the easiest way to drain down and disconnect the four hose / cables to the furnace body and two hose to the chiller, and also the inner passageways of the Furnace Driver with minimum loss onto the floor and maximum retention of the expensive glycol solution. I have in mind to sacrifice my 'Clean' wet & dry vac to this purpose. It's supposed to be reserved for vacuum hold down fixtures on the CNC mill - I supopose if it suffers they are not THAT expensive. My (identical) workshop vac is disgustingly filthy and any liquid recovered using it wouldn't be worth saving !

Doing an inventory of the rusty bits just now and making a photographic record they are quite extensive  - all external surfaces need doing but amazingly the internal surfaces have faired far better - the door and panel seals must have done a good job of keeping the moisture out.

I must admit I'm not looking forward to this bit of the project. It wasn't worth doing before I'd proved that the unit worked, and now I know that it does I'm loath to take it apart, but if it's not done now it never will be, and those rust spots will become far more of a problem to deal with.

The plan is to remove the six castors from the base frame, sit it on it's adjustable feet and move it about with the pallet jack. (I fitted the six castors at my last place as there was no room to get the pallet jack at it, and four castor weren't rated for the weight !)



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 13, 2020, 05:25:49 AM
In a flash of inspiration in the early hours of last night I remembered that I had a Numatic car valeting wet & dry vac tucked away on a shelf in my container that I had bought off eBay 'as it looked useful'. I think that it's only been used once by a friend who had had a smashed windscreen and cubes of safety glass everywhere.

Emptying the glass (!!) and washing out the innards and hose it was eminently suitable for sucking up the coolant as it escaped as I undid various plumbing fittings. In the end I managed to  're-cycle' three gallons of coolant, which I passed through a fine mesh filter. So not only is that three gallons of not inexpensive coolant saved, it's three gallons NOT on the floor to mop up  :thumbup:

Applying the vacuum hose to the two large flow and return ports on the furnace driver effectively sucked out not only the inner workings of the driver unit, but also the hose / cable assemblies leading to the furnace body. This made undoing them easy as coolant wasn't splashing everywhere (as it has in the past!)

So that's Phase One completed :thumbup:

Next - Phase Two, remove the castors . . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: nrml on June 13, 2020, 06:49:08 AM
It's a bit late to be of any use now, but wouldn't one of those air driven venturi vaccum coolant filling devices been ideal to just suck it all out from a low point in the circuit without any mess at all? With all the coolant and various other fluids you use across your workshop, you could do with one of those. They are pretty cheap these days.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on June 13, 2020, 10:51:19 AM
I have one of those Numatic vacs as a shop vac for swarf and general dirt. They are fantastic for both wet and dry. They do single and twin-motor variants.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 13, 2020, 11:04:43 AM
A good solution, thank you, but the Numatic actually worked quite well. I had one of those venturi coolant mixers but I sent it back and got my money refunded, as the mixing ratio quoted was miles off what I could measure with my Brix gauges

So Phase Two starts :-

Firstly the six castors. It seems that I'd drilled and tapped to fit them, so getting them off was easy with no struggling to reach nuts - probably why I did it that way!

Then I removed all external labels, door furniture, operating handles, locks, catches, captive bolts etc. Then for the operating panel. This is not an 'unplug' job - some is but most is hard wired. I worked out that there was just enough cable length to remove it from the front door, and fold it back into the cabinet. I wrapped it in bubble wrap, and as luck would have it the 3 phase sub-panel cardboard box was just the right size to secure it in, and tie it with the ubiquitous baler twine.

The main input 125 amp socket I knew was going to be an issue to remove. Held on by four M6 bolts into thread inserts, but one had cross threaded and pulled the insert out of the panel, and getting to he rear was pretty impossible being more than I could reach through the internal electronics from the other side. There was JUST room to grip it in a Mole Grip, closing it with the tips of my fingers. Mole grips tethered with another bit of baler twine, as when (if) the screw comes out the Mole Grips will plunge into more inaccessible space below. However a quick application of the rattle gun to the bolt head working against the inertia of the mole grips got it off, and as expected they went crashing into the depths but was able to be pulled out by string.

So I think that's Phase Two completed  :ddb:

Major paint stripping and rubbing down next. I think that I will swathe the internals in dust sheets - do all the stripping and rubbing down, then remove the dust sheets and mask up properly before spraying.

I'm in two minds how to handle the doors. As they are at the moment they would just lift off their hinge pins, and that would make preparation of the frame somewhat easier, and preparation of the bottom edge of the doors would be a lot easier. I may lift them off, prepare them and the frame, spray the frame then re-hang the doors for spraying. Not decided . .  :scratch:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 14, 2020, 04:38:47 AM
So - Phase Three: Prepare for Spraying.

This morning I went over all surfaces with a rotary wire brush removing loose paint and rust. This helps to reveal and take off bits of loose paint that superficially appear sound but actually are separated from the base metal. It also saves the stripping disk (which is the next process) - also rotary wire brushes last longer and are cheaper !

The wire brush leaves a harsh step between the remaining sound paintwork and the base metal, whereas the stripping disk (if used gently) allows you to blend the junction.

So four sides and the top took about an hour so I was finished by 9 am and came in for my fingers to stop tingling from the angle grinder and have a coffee. Hopefully using the stripping disk wont take much longer, though it does need gentler application.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 14, 2020, 11:28:26 AM
So to complete Phase Three took one and a half stripper disks and as expected took a bit over and hour for the stripping and about as long again to mask up for spraying.

I liken masking with paper to hanging the cheapest wall paper that you've soaked too long in paste - it tears at the first excuse!

Covering up the innards took a bit of taping ingenuity as of course you cannot get to where you need to put the masking tape - never mind I got there in the end - not the most robust, indeed I had to drop the roller shutter as the slight breeze threatened to blow it all off.

So Phase Three completed  :ddb:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 14, 2020, 11:39:24 AM
Onwards with Phase Four then - spraying.

While the gun was very full and would still spray canted over, I sprayed the lower lips of the doors and panels. Then up the ladder to get a coat on the roof, followed by the exposed frame.

That gun full ALMOST did the right hand panel and surround, but needed a refill to do the remaining three doors - pretty much exactly two gun fulls to finish this coat.

Although it's dry now, I'll leave it over night before it gets the next coat. One or two places need rubbing down a bit - seems that I disturbed a spiders web over head with the air from the gun which got embedded in the paint.

Second coat definitely needed as it's not exactly uniform in density in places.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on June 14, 2020, 03:09:25 PM
No runs Andrew, thats the main thing, I am painting the welder tomorrow, same paint but in green!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 14, 2020, 03:17:57 PM
A quick light flash coat over the panel then come back and give it the proper coat usually prevents runs.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: JerryNotts on June 15, 2020, 03:28:20 AM
Morning Andrew,

Nice to see some carefully done spraying.

You don't say what size your gun pot is but there are a lot of different capacities. You could go for a pressure pot, say 5 litres, olde non-metric gallon pots can be found. Use with sufficient pot pressure to push the paint to the gun inlet can work fine. I trust you set-up is a  decent make.

Jerry
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 15, 2020, 05:10:51 AM
Hi Jerry, the gun is a Binks-Bullows 230 that I've had for Donkey's Years ! - must be getting on for 40 years old! Capacity - not sure but probably about one litre.

So having remembered to replace the Rivnut that had pulled out that holds the 125 amp input socket I got on with spraying the top coat. First I rubbed down with a green Scotchbrite pad to remove a few bits that had settled on the job yesterday, and then mixing a carefully measured 10% thinners as recommended had to it.

I must say that 10% with this paint and with my gun and nozzle is a bit of a struggle - I wanted to try and keep to the recommendations to get a decent dense coat, but in the end added a further splash of thinners - it may be that my nozzle is too fine, but it's the only one that I have !

It's an acceptable job, but I could criticise  it if I had to - it'll be far better when all the door hardware and labels go on to take the eye away  :ddb:

So that's Phase Four completed.

Phase Five - put it all back together - starts tomorrow.

So . . . a paint drying day for the rest of today with a bit of  :coffee: and later  :beer:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on June 15, 2020, 02:58:58 PM
Nice job Andrew  :thumbup: :thumbup:

Can't wait for the first melt!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 15, 2020, 03:05:28 PM
Thee and me mate  :clap:

I did rescue a rather tacky cast iron 'well hand pump' of the Chinese variety from a friends skip the other day thinking that it could be the first victim to melt  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on June 15, 2020, 05:06:46 PM
Thee and me mate  :clap:

I did rescue a rather tacky cast iron 'well hand pump' of the Chinese variety from a friends skip the other day thinking that it could be the first victim to melt  :clap:

That makes three!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on June 15, 2020, 07:05:33 PM
I’m looking forward to your first melt. Are you going to try greensand or mix a batch for cast?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 16, 2020, 02:28:55 AM
I will probably use sodium silicate and silver sand.

When I’m at that stage I’ll start a separate thread
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 16, 2020, 12:04:53 PM
Yesterday afternoon I stripped off all the masking paper and had a nice anti-social bonfire of it in an oil drum brazier with all the paint rags creating a brief but impressive black plume. Lucky we have no near neighbours  :lol:

And this morning I started putting it all back together - bang on cue Parcelforce delivered the little 3 mm plastic rivets from RSComponents so I could re-attach all the various labels and warning signs.

Before I re-connected it to the furnace body I cut the Ty-Wraps holding the four Brewers Hose driver cables and re-arranged them to lie a bit more uniformly before binding them back together with more Ty-Wraps.

Then having attached to furnace body, and the flow and return hoses from the chiller I was able to test for leaks and start pumping water round the system - all sound thank goodness.

Using my 'test mains cable' I was then able to power it up off local three phase, check that it goes ready, and 'ping' the furnace body - it's still working amazingly.

So - next job it to sort out a way of having the high power cable from the generator permanently connected. Rolling it out each time is a major exercise and means that I can't fully lower my roller shutter so I can't leave it as is.

I need to work out whether to trench in the big 6" electrical ducting that I have, or whether either laying it on the surface  or fixing it to the rear wall of the barn is the best option. A bit of cogitation called for  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 16, 2020, 04:57:35 PM
It looks like new. Another Mawson success  :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 16, 2020, 05:17:25 PM
Thanks Graham.

Do you remember that heart stopping day when we realised that it had a 15 year old back up battery and shot out to the workshop to investigate  :bugeye:

That was nearly curtains for the project!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 16, 2020, 06:24:32 PM
I certainly do, Andrew. I'll be sorry to miss the inaugural firing of the first load, unless things ease up, of course  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 17, 2020, 01:53:16 AM
Graham you probably wouldn’t want to be closer than two meters anyway so I don’t see that a visit would be a problem.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 17, 2020, 11:41:26 AM
Keep me posted then  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 17, 2020, 04:20:49 PM
I won't be long Graham.

This evening I've bought an 18 metre length of brand new 4 core 35 mm csa SWA cable on ebay at a pretty cheap price (£54) and have put it up on Shiply for quotes for delivery (it's in Kidington, Oxford) . By co-incidence the best so far is from the chap who delivered the two humongous Heat Exchangers, one of which went into the new water cooler. They totalled 75 kg - this cable in 'only' 50 kg !

This will enable me to direct bury it in the earth between the generator and the foundry without any conduit and have enough either end to fix a plug and socket in convenient places. I already have a 10 metre length but it only just reaches and it's ends would have to be in darn inconvenient places.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 20, 2020, 06:35:26 AM
The extra 18 metres of 4 core 35mm csa SWA cable is due to arrive this afternoon so I need to consider how to get it into the foundry from it's proposed underground trench.

It's not very flexible, and needs to raise from horizontal in it's underground trench to vertical up the inside wall of the foundry, so just drilling a hole through the wall won't work due to the minimum bend radius of the 30 mm diameter outer sheath . I hit on the idea of core drilling a hole at 45 degrees through the corner of the concrete slab / wall junction. Then when the trench is dug it can slightly under mine the slab and the cable can take up a somewhat gentler bend.

So using my diamond core drill and both the extensions that I have for it I drilled the hole. It ended up about 14 inches long. Sounds simple doesn't it but producing that hole represents two hours of my life :bugeye:

My core drill perhaps doesn't have as many diamonds as it used to have, and I had to alternate between two drills as they were getting mighty hot so . . .

. . . . it may look like a pathetic little hole to you but to me it represents an achievement  :ddb:

Now I need to find someone to hand dig 20 foot of trench as, the state my back is currently in it's not going to be me  :(

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 20, 2020, 12:30:13 PM
I've made a note in my diary.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 22, 2020, 12:19:26 PM
A bit of an update:

A/ The 18 metre length of 4 core 35 mm CSA SWA cable arrived as promised late Saturday afternoon.

B/ I have been ordering the bits needed to make up the permanent installation (Glands, CC12 cable clips, a Male and Female fixed plug & socket, and male and female free plugs & sockets, and an underground poured resin cable joiner) and some, but not all,  bits have arrived.

C/ I have a volunteer 'trench digger' who was due to do his stuff this evening but as his Sister in Law has been rushed into intensive care that's off the menu.

D/ I've had a friend unroll the alleged 18 metres of cable and measure it both physically and electrically - it's 18.1 metres (so that's OK) and electrically sound, as is the 10 metre roll and also the 28 metres of flexible cable (despite it's antiquity)

The current (!!!) plan is to run the SWA so that the 'underground resin joint' is actually above ground inside the foundry - this is convenient for the two cable lengths and means that the male and female wall mounted plug and socket can be mounted immediately adjacent to the generator and furnace driver respectively and it minimises the amount of cable needing pulling through that 50 mm concrete hole that I drilled on Saturday reducing the risk of damage to the sheath.

But frustratingly I've not personally been able to do anything but be an onlooker to these activities as it seems I've either trapped a nerve or possibly pulled a muscle in the vicinity of my left hip and cannot be on my feet for more than about a minute before being in agony. Hopefully it'll sort itself out after a few more days but this is day three already  :( If it goes on much longer I'll need to order a Zimmer Frame  :bugeye:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on June 22, 2020, 12:55:13 PM
Look after yourself!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on June 22, 2020, 01:33:06 PM
I'd offer to help, but I'm not in much better shape. I've had really painful knees for some weeks, difficult to squat down even. Still, starting to get better finally. Hope you mend soon Andrew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete W. on June 22, 2020, 01:47:25 PM
Andrew,

Get well soon.  I wish you that for your own sake, not for the sake of us rubber-neckers on the telegraph wires!! 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 22, 2020, 01:56:31 PM
Thanks chaps. The trouble is none of us are getting any younger but we still expect to be able to do what we used to do.

Personally I find it quite embarrassing that I have to watch friends doing what frankly is a none-essential activity - they are apparently very willing but accepting help I find remarkably hard - it's usually me solving issues for others  :bang:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on June 22, 2020, 03:30:28 PM
Get well soon Andrew! you sound an awful lot like me, it has been said that I am not good at accepting or asking for help from others too! Hope you are soon better.
Phil, East Yorkshire.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on June 22, 2020, 05:10:27 PM
.....
But frustratingly I've not personally been able to do anything but be an onlooker to these activities as it seems I've either trapped a nerve or possibly pulled a muscle in the vicinity of my left hip and cannot be on my feet for more than about a minute before being in agony. Hopefully it'll sort itself out after a few more days but this is day three already  :( If it goes on much longer I'll need to order a Zimmer Frame  :bugeye:

Have you seen a competent doctor?

Two months ago my wife had incresing back pain (not uncommon for a witress/cook at all). She got prescription of pain killers and started biking in addtion to our daily 5-10 walks, but it got worse. I started to think it's Sciatic nerve....such were the symptoms. She had a day off when she clound not stand any more, one leg would go limp. The pain was nearly intolerable.

I took her to first aid and they only wanted to know if she had corona...no.no.no just back pain. She met a doctor, they run tests, took x-rays, could not conclude, but admitted her in and scheduled for more tests and MRI. Right after MRI hell broke loose and they scheduled her for back surgery next day. They removed pound coin size tumor that was pressing all nerves on lover back and causing **** load of problems.

She was admited home next day and was adviced to start walking slowly. She made it to mail box, bout 10 meters first morning. You can imagine that that was pretty bad for morale....but she doubled every day and after six weeks she is biking 30-40 km on one go (once or twice a day) and we still have our daily strol of 5-7 km.

She is not alowed to lif anything more than a kilo or twist her back, but could start working soon. She said that pain went away right after surgery and she can move more freely than months.

Chances of you having same type of problem is low, but I would advice to be checked if there is no clear and obivious reason for the back pain.

Get well

Pekka
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on June 23, 2020, 04:17:36 AM
Thanks chaps. The trouble is none of us are getting any younger but we still expect to be able to do what we used to do.

Personally I find it quite embarrassing that I have to watch friends doing what frankly is a none-essential activity - they are apparently very willing but accepting help I find remarkably hard - it's usually me solving issues for others  :bang:
Welcome to the Club, Andrew. Get well soon, although you can't get younger...
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 23, 2020, 05:21:34 AM
Thanks for your comments chaps - I'm going off this old age thing rapidly ! Pekka I'm sorry to hear about your wife, and am glad to hear that she is recovering, please give her my best regards.

Following prompting by Pekka's suggestion and also that thing's aren't getting any better I had a 'telephone consultation' with my Doctor this morning - Covid 19 still stopping normal visits - he reckons that it's muscular and is proscribing stronger pain killers - I hope that he's right!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on June 23, 2020, 05:43:24 PM
Thank you Andrew, I relayed the greetings and she said that "hope it is muscular and starts to get better soon, if not: you need to be checked". Her recovery is remarkable, we went swimming on the lake. And drove nearly 50 km on one go. No problems. Huge improvement and most importantly: no pain and she feels she is recovering fully.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vintageandclassicrepairs on June 24, 2020, 06:58:10 PM
Hi Andrew
Get Well soon  :wave:
I know how it feels to be stuck looking at "things to be done" and unable to get on with them
I'm on my third week with a crock knee, but have been able to get to see a doc get an MRI and have a physio appointment tomorrow, I am not going to let them do much until the MRI report arrives

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 25, 2020, 06:38:29 AM
Thanks chaps for all the good wishes I'm touched (people have been saying that I'm touched for years!)

John I hope that gets sorted soon - as you say extremely frustrating having things needed doing but your body won't co-operate.

Well I don't believe in miracles, but I had one yesterday (*) and I can now stand without screaming pain, so long as I limit the time that I am 'up' and this has allowed be to do a couple of minor jobs to at least keep a bit of forwards momentum.

Firstly I did a bit of carpentry and fitted a ball catch on the double doors between my main workshop and welding shop - been meaning to do it for years and had ordered the catch last week. They  used to blow open and bang if not bolted and were quite an annoyance.

Having found that my 'new body'  coped with that I mounted up the final 125 amp female socket where the SWA cable will terminate - only four 8 mm holes through an RSJ but at least it's done now and makes visualising the cable run easier. Having done this it confirmed me in the belief that the input socket on the Furnace Driver should be rotated 90 degrees to keep it's umbilical cord shorter and out of the way of the pipe/cables that go to the furnace bodies.

All little things but at least they are done.

(* my miracle - I'd spent a hopeless night racked in pain, only manged to get downstairs by hauling myself inch by inch prone on the floor to a chair in our 'snug' and was there for a while when nature called. Trying to walk I got about four foot before having to fling myself chest down onto a 'pouffe' that my wife uses as a foot stool and slid it towards the 'facilities' breast stroke fashion with me on it. Having 'done' I got up cringing in anticipation, but ,no pain - hang on I'm upright what the heck has happened? Since then although I get a bit of pain if up for more than about 5 minutes the agony has gone. I can only assume that throwing myself horizontal onto the pouffe  bent me in a way that released whatever nerve was trapped.)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: NormanV on June 25, 2020, 10:43:30 AM
I have a heart warming story about back pain. I used to live on the Isle of Wight and one friday I was on the train arriving at Lymington to catch the last ferry that day to Yarmouth.  As I got off the train my back seized up and all I could do was cling onto a bollard and watch the boat sail away. To my amazement it did not move and I was eventually able to hobble on board. Thank you to the captain who must have seen me from the bridge. If the boat had sailed it would have taken me at least three hours to travel back to Portsmouth and catch another ferry.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on June 25, 2020, 02:22:48 PM
Good news Andrew! Glad to hear your Pouffe gymnastics seems to have fixed the problem, but light duties for the next few days please!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on June 25, 2020, 02:32:43 PM
A similar thing happened to my stepson a couple of weeks ago - he was hobbling about with a very sore back. at work he hopped over a low fence and when he landed all his pain disappeared in an instant. Been right as rain ever since.

I'm glad you're feeling batter Andrew. I don't suffer back problems but on the rare occasion when I do something silly and give myself a twinge it tells me how lucky I am.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 25, 2020, 03:40:29 PM
Thanks chaps - Norman I know that ferry (and missing it) only too well, call outs to computer problems at Albany Prison always seemed to end with me sleeping in the car having missed the last ferry :(

So this afternoon I decided to tackle terminating the 10 metre length of 35 mm CSA four core SWA by fitting a waterproof gland and making it off on the 125 amp socket that I'd mounted earlier.

This cable is particularly stiff, the cores having been compressed into pie slices and the copper being hard drawn bending it is great fun. So much so that I decided that I had no chance of leaving the socket on the wall, I'd have to dismount it and make off the cable on the ground.

Although it is big, it's construction is just like smaller SWA in that the cores get gripped between a conical part and a tapered ring to physically grip the cable and also provide earth continuity. Somehow I lost the taper ring - searched high and low, was about to use the ring from the second gland only to find it exactly where I was working - I reckon that the Pixies are teasing me  :clap:

Now I've picked up a couple of useful SWA tips recently watching YouTube. When trimming the cable shroud, first push it in reverse onto the cable, then just trim where it bulges - so simple! Then when the gland and cable are loosely put together run a fixing nut onto the thread and use it to tap the taper assembly firmly together before tightening the conical bits to get a well packed tight cable.

You can tell you are working on big cables when you have to use Stilsons to grip the nuts as you have no spanners big enough  :bugeye:

Getting the cable cores into the 125 amp socket was hard work as they just wouldn't bend, but eventually they all got into the right holes (I hope!) and were made off.

Then to re-mount the socket - due to the rigidity of the cable I had to use long bolts to slowly pull it into place then once there I replaced them one by one with the correct length. While this was happening I had loosely suspended the cable from the Z purlin that it would be attached to by CC12 cleats to get it roughly in place and take the considerable weight.

OK socket mounted, then I worked across the Z purlin fitted the CC12 cleats with 8 mm bolts and temporarily laid the cable behind the RSJ that it will be cleated to hopefully tomorrow.

The cable end currently dangles close to where I bored that 45 degree hole in the concrete. I will bring the other (18 metre) cable in through the hole (once the trench is dug) and they will be joined with a cast resin junction of the type intended to be buried.
 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on June 25, 2020, 04:25:09 PM
Good work Andrew, but hardly light duties!! I remember with horror my apprentice days of running 400a submains underground, in winter, and trying to unlay the cable off a drum and down the side of the trench to get the twists out of it. The boss insisted we could do this job, even though we had no drum stands and large cable gear! I remember being one of three apprentices who were lifted bodily off the deck and chucked across the trench when we lost control of the loops we were trying to unroll towards the switch room, Bend it? We couldnt! We used to fit the switchgear wherever we could get the cable to run to!  Them most certainly were not THE days!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vintageandclassicrepairs on June 25, 2020, 07:00:00 PM
Hi All,
Good to hear you are back at work Andrew, Mind Yourself !!!
The physio gave me some good tips today and a different knee support has relieved some of the pain
After 35+ years of working as a spark, I can appreciate the difficulty terminating the 35Sq having done it many times. One bad one was having to re terminate a 4 x 120sq lying on my back in a cable duct underneath a panel !! the failure happened near the end of a 12 hour shift and with commissioning engineers back on site first thing in the Am we had to work on through the night to do the repair
I'm paying the price for all that stupidity now  :(

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: edward on June 26, 2020, 04:02:10 AM
Excellent stuff as usual Andrew.

I am pleased to see that someone other than me uses those 'Safe-T-Crocs' work shoes :)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 26, 2020, 05:59:08 AM
Edward, I get through three pairs a year at least !

This morning I finished off cleating the cable to the RSJ up in the gods. It's amazing how inventive you can be using the ubiquitous baler twine to haul things into position while you are trying to get a cleat, a bolt and a hole all lined up at the top of a ladder at the same time as an Anaconda is fighting you  :lol:

Oh - and I topped up the Chiller tank with about three gallons of anti-freeze solution - it had been drained off when I 'unplumbed' for painting.

So now activity is dependant on getting that short trench dug - I put out feelers locally as there was a chap looking for outside work - it's only nine yards long by a spade wide and deep so nothing for a youth (!) - but not heard back yet.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 27, 2020, 06:50:46 AM
At last the trench is dug  :ddb:

A friend of a friend came round this morning and kindly dug my trench - quite a big excavation initially to get a good angle to access the end of the 45 degree hole that I'd bored some days ago through the concrete. And of course it HAD to emerge just where years ago there had been a 6x6 fence post concreted in. Once the remnants of it's concreting in had been broken away life got a lot easier - the trench was brought up to about a spade depth and continued to the complicated corner where all the water pipes are currently exposed.

The corner of the concrete slab will need cutting off to bring the cable into the stable at a more benign angle and another friend is hopefully coming this afternoon to help me with that, and actually pull the cable though the hole.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 27, 2020, 12:47:52 PM
My friends came this afternoon and between us we got the cable pulled through the hole in the concrete using a bit of waste pipe as a sleeve to protect its sheath.

About 4 metres extra was pulled through to allow the bend of the cable to turn 180 degrees for jointing in the resin joint. Once that joint has been made and tested the excess cable will be pulled back into the trench and into the stable.

The corner of the concrete by the stable was cut off and again the  cable sheathed in a bit of waste pipe to protect it as the excess length is pulled back.

So, a resin joint to make off, a 125 amp wall mounted plug to make off, and two relatively short flexible umbilical cables to be made and apart from back filling the trench we are there  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 28, 2020, 11:38:04 AM
To more easily tackle the resin joint I decided to make an assembly jig to hold the two cables firmly, and pointing concentrically at each other. A couple of plasma cut steel plates mounting four suitably spaced cable cleats elevated on bits of 4x2 and screwed to a board.

It's just as well that I did this as assembly was a bit of a pain. I came across an issue that has never occurred to me before - the two ends of a cable are DIFFERENT. In this case looking at one end the cores read clockwise L1, L2, L3, N BUT the other end reads (again clockwise) L1, N, L3, L2. Now usually this doesn't matter a jot, but in this case where four heavy cores are being crimped in a tight space, and are separated by a cross shaped piece of insulation, two of the cores have to cross over no longer leaving a space for your cross shaped insulator  :bang: Had I realised this earlier I could have threaded the last cable starting at the other end, and the cores would have all been flowing the same - but too late for that. A bit of ingenuity re-manufacturing the cross shaped insulation and forming the cores with a mallet to ensure adequate spacing, and an assembly was formed that was JUST compact enough to go in the plastic shell ready for pouring the resin. Before the actual pour I did an insulation test at 1000 volts and got well over 500 M ohms.

It is now probably already cured, but I will leave it overnight just to be sure as manipulating it into place and pulling back the excess four metres of cable is likely to put a bit of strain on it - certainly it will need a further insulation test before powering up.

. . . hopefully that's one more milestone ticked off the list  :thumbup:


 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on June 28, 2020, 11:52:12 AM
There is always something trying to trip you up  :doh:
John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 28, 2020, 02:03:55 PM
John, if life was simple it wouldn't be fun  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on June 28, 2020, 07:26:48 PM
are you sure the electrons can go down the wire in the wrong direction? :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on June 29, 2020, 02:31:03 PM
I would leave the jig on whilst you get the cable into place, if thats possible. I once had to attend one in the middle of a field, and wondered how I would find it, don't you worry bout that said Mr farmer, you just stand there and watch yonder, and toddled off to switch on the power in his deep litter hut, After a few moments, a little column of steam could be seen rising from the ground, and it was promptly dug up, to find that the cable had not been laying flat on the bottom of the trench when the joint was made, and as a result the joint had cracked across the resin, I was able to cut 6" off both cables and still have enough to remake the joint. It has given no further trouble, but I must admit those jointing kits are not my idea of fun! This one was the type which used four little line tap type connectors with plastic boots to cover them.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 29, 2020, 03:00:08 PM
Well Phil great minds seldom differ - that's EXACTLY what I did !

Oh - Boy what a day - lots done but long and intensive.

While I was waiting for a friend to help me push the four metres back down the hole I made some careful measurements and cut 2.4 metres off the 10 metre flexible conductor, and fitted a further 125 amp fitting to convert it into the 'short umbilical'.

Then my friend turned up, and just as Phil suggested I kept the cable jig on the cable until the last minute as we pushed, pulled and cajoled the cable back down that hole. Once this was done I cleated either side of the resin joint fixing it firmly to the wall inside the foundry. Then I was able to pull the excess cable into the stable and cleat it to the wall at a height that hopefully will stop it being knocked ready for the end  wall mounted 125 amp plug to be fitted
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 29, 2020, 03:35:33 PM
Then it was a case of making off the SWA into the male wall mounting 125 amp plug. Having had a problem at the other end I had this time plasma cut some large spanners ready to fit the gland.

Opening up the plug it was revealed that there was no way to make off an SWA gland in it's 'bulkhead' and have enough free cable movement to pull the actual plug unit out to access the cable fixing screws - the whole thing slides into a shroud about 50 mm deep that completely obstructs the cable screws :bang:

The only solution the we could come up with was to saw the bulkhead horizontally through the 32 mm gland entry hole and remove temporarily that bit of the fitting. Then the cable and gland could go deeper in giving room to get the cable ends into their sockets AND fix their screws - the the gland and cable could be pulled back 50 mm and the gland seated in it's now halved hole, and the other 'half of the hole' re-assembled before the gland nut was tightened onto the banjo earth fitting and bulkhead. All rather fiddly and essential to get the cable length EXACT or it wouldn't fit. This took three assembly / disassembly sequences before it was right.

Eventually the cover could be re-fitted and that fortunately also serves to clamp the two halves of the bulkhead back together. Time to screw it to the wall . . .

. . . . arg . . . Houston we have a problem . . I'd assembled it 180 degrees out in the casing. The socket that mates with this plug has a spring loaded lid that needs to be away from the wall or otherwise there is no room for it. Not just a case of rotating in the housing as no way would this cable rotate 180 degrees in less then a few metres  :bang:

Fortunately a friend pointed out that as the plug / socket will effectively be permanently mated the lid is redundant - take it off. So I did  :clap:

At this point we did an electrical leakage tests at 1000 volt and continuity check - all good  :thumbup:

Time to make up the longer umbilical cable. This used the rest of the 10 metre flexible cable so 7.6 metres - I opened up and checked the already attached plug, cleaning up a bit of corrosion, and fitted a free socket to the other end. This umbilical runs from the wall plug up along the RSJ structure of the stable and down to the socket on the generator.

Gosh - fixed wiring FINISHED  :ddb: :ddb: :ddb:

Time was getting on and domestic pressures were mounting, but I did manage a very brief test - again getting a bar glowing in the crucible. I ran everything up to about 60 KW and nothing went bang or got hot apart from the contents of the crucible.

More testing tomorrow  :zap:

I have managed to source a large three phase RCD unit that has selectable over current tripping (125 to 160 amps) and  selectable leakage current tripping (30 mA to several amps) so I will be fitting that to the generator for peace of mind when it arrives, and I also want to improve the earth bonding of the generator, the Furnace Driver, the new Chiller Unit and the particular Furnace Body that's in use. I'm intending to also earth bond the steel structure of the foundry building to these units and the steel structure of the workshop.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on June 30, 2020, 12:51:30 PM
Today was largely taken up with other domestic matters, but a run of surface drains that had become clogged with pea shingle afforded an opportunity to use the recovered gravel back filling the cable trench.

This is overkill, 'as dug' back fill would be perfectly adequate so long as sharp stones are removed, but as it was there the cable got bedded in the shingle, then a few inches of earth followed by a row of roof tiles (anti spade penetration!) more earth, then a warning tape before fully back filling to surface level with more earth.

No doubt it will settle, and the far end by the stable is still 'open' as there are water modifications to do before closing the trench. When that's done it can all be re-seeded, and a bit of normality regained!

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 01, 2020, 05:35:20 AM
So let's try and actually MELT some metal  :bugeye:

First I carefully scraped out the crucible that is embedded in the inverting 'Furnace Body' and removed some iron slag and very small traces of copper slag. (Remember that I installed this crucible brand new many years ago, so this confirms that in the past I have melted both iron and copper with this beast). It's an awfully long time ago and I've had various furnaces over the years, so what was done in which gets a bit hazy !

Then, as I had no mould prepared, I selected a conventional crucible from my stock that would sit inverted on top of the furnace body, and when clamped and inverted would receive the molten metal - let's call this the 'drop crucible' (and hope we don't !!!!)

A test clamp, invert, release and all seems well so I charged the main crucible with a bit of copper scrap left over from the installation.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 01, 2020, 06:15:45 AM
So :-

A/ Start the generator and close it's isolator

B/ Turn on water stopcocks from Borehole, which automatically starts the borehole pump

C/ Power up the New Chiller Unit and check for water flow

D/ Turn on the massive main switch on the CFEI  and 'Ping' to measure resonant frequency

E/ Check Compressed Air is 'On' to Furnace Body

F/ Change CFEI Keyswitch from 'Test Frequency' to 'Normal'

G/ Wind the power control to minimum and press 'Chauffe' keeping fingers crossed!

H/ Slowly turn the power up to initially 67 KW then 75 KW listening to the generators 'note' getting harsher.

I/ Watch things starting to smoke then glow very hot.

Now I have no recollection of this happening previously, but a light saying 'Limit' comes on around 75 KW and no further increase seems to be allowed - it must be a pre-set parameter but as I say I have no recollection of it. In fact the display tops out at 77 KW.

So, watching the pot, things are getting extremely hot but no apparent melting happening - the long copper pipe had a dribble of molten metal down its side which formed a cut in the tube, but it's not forming a pool in the base of the crucible as I had expected.

I left it running at 77 KW for a while, and went to inspect the generator which was running magnificently but nothing looking untoward - I took a picture of it's control panel showing 150 amps of load but it's come out very fuzzy - either I was shaking or the camera didn't focus!

The chiller unit using the bore hole water seems to be working fine - I think that the maximum return temperature from the furnace was 34 degrees C - it's picture DID come out OK!

So, ramping the power back down I shut everything off and inverted the furnace body to drop the result into the drop crucible.

When it had all cooled I could then examine the results - each pipe section had. like the long one, a melted bit down it's length that had turned the complete circumference into a 'C' shape.

My theory -and PLEASE COMMENT if you have other theories is as follows:

The furnace melt metals by inducing eddy currents into the charge by transformer action, the charge effectively forming a short circuited secondary winding. Here the pipes having broken the circle are no longer carrying the major current that they were.

I think, given a reasonably dense initial charge that will form a pool in the base, and absorb much of the power, further small stuff will melt into the pool quite satisfactorily

Time for more reading and experiments, but I'm being called away on 'other matters' at the moment.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on July 01, 2020, 07:53:33 AM
Can you start with something dense, as you suggest, but maybe aluminium or even a small coil of copper wire?

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 01, 2020, 10:44:07 AM
If at first you don't succeed, try, try again  :lol:

I've had a lump of what I'd thought was copper at the back of my bench for years - rescued from the scrap of my foundry when I moved all those years ago, so I thought I'd try and melt that - about 5 kg.

Well it was too large for the crucible on the inverting furnace body so I started cutting it in two on the band saw. I wasn't entirely surprised when the blade broke - copper can be gummy, it was over an inch thick and far from stable on the saw table. Never mind, finish it with the Angry Grinder with a 1 mm disk. Now soft copper and disk cutters don't go well together, so why was it cutting so well :scratch: Because it's BRASS  :clap: It had only looked coppery as the surface had been de-zincified.

So now it fits in the pot I went through same rigmarole turning everything on, ran it up to 75 KW - took a decent picture this time of the generator panel (!) returned to the foundry and it was already practically melted. Another less than a minute and the zinc was boiling off, time to invert the furnace.

I got a little bit of brass splash as it went over - I was probably a bit too slow doing it - then the furnace driver gave me an error light. (Water pressure or temperature to / from furnace body but not sure which)

Everything turned off, drop crucible released, and a 2.5 kg dome shaped lump of brass was deposited on the floor.

It was at this stage things got a bit hectic as one of the brewers hoses that carry the chilled cables from the driver unit to the furnace body decided to burst and squirt coolant onto the floor.

Now this is not entirely a negative, as it will persuade me to replace them despite the not inconsiderable cost, and it is best for safety anyway.

So this escapade had proved that the furnace is fully working, albeit that I have a few issues to correct.

Quite impressive rate of melting - 2.5 kg of brass in about 5 minutes - actually probably a bit less as I'm taking that timing from time stamps on the photographs.

. . . off now to cost rolls of Brewers Hose  :bugeye:


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on July 01, 2020, 12:48:56 PM
I think you will have problems melting Things that are only a few skin depths in one dimension.

I've seen that worm tracking thing back when I tried to build a RF shunt to handle a kilo amp using thin brass sheet.  Some kind of field concentrating thing going on that runs away gleefully with positive feedback.

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 02, 2020, 05:34:36 AM
Bowing to the inevitable I removed the cables / hose assemblies this morning, measured them up and I reckon in the current layout I can shorten them all by about one metre for a neater 'lay'.

Order placed with Anchor Pumps, who are the people who supplied the  ceramic seal kit for that Grundfos pump by co-incidence, being the best value that I could find.

While I was at it I also ordered some reinforced neoprene 1" bore hose to replace the reinforced PVC that I'd fitted, reckoning that it'll be a bit more durable and things will already be drained down so relatively easy to do.

Bits should arrive mid next week. I now need to work out how to clean the ends of the 70 mm CSA welding cable that passes up the hose to a standard that will let me braze it to the fittings. Acid dip probably. As I recall I made a 'cup' shape on the fitting that passes into the hose and  receives the cable, the hose being pulled a fair way down the cable and clamped to keep it away from the heat. Then the clamp is released, and the hose pulled onto the 3/4" body of the fitting and secured with two 'Band-It' stainless clamps.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on July 02, 2020, 05:47:38 AM
Phosphoric acid should do the trick. Or maybe Baker's fluid.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on July 02, 2020, 10:10:52 AM
Phosphoric acid should do the trick. Or maybe Baker's fluid.

Baker's fluid for Brewer's cables?

Suddenly I am hungry and thirsty!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 03, 2020, 09:06:08 AM
Very good Ade  :clap:

Amazingly the replacement Brewers Hose and also the 1" bore chiller feed hose has arrived this afternoon - I only ordered it yesterday and it wasn't due until next Wednesday !

Now this is good, but I daren't start to re-make the hoses as I've got heavily involved in a bit of water diversion, re-using a redundant 20 mm feed that comes from the domestic garden / garage up to the barn and was crying out to be connected to the bore hole water system for garden watering. Intercepting the pipe down by the garage was easy as a manhole / stop cock marked it's run, albeit 4'6" deep (Remove stop cock, cap pipe, extend other part of pipe up wall to a tap) but to do this the water feed had to be turned off. BUT when I came to turn it back ON it was jammed closed (plastic tap) so although the house still has mains water, nowhere else (including the loo in my workshop or any of the animal troughs  :() does. And getting at that stuck stop cock involves digging up the patio. The other end by the workshop / borehole pump was dead easy, just inserting a 25 mm Tee fitting with branch reduced to 20 mm - and is now all live and awaiting back filling.

. . . so I daren't start on those hoses until this mess is cleared up  :bang:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 03, 2020, 02:08:49 PM
Thank goodness normal service is resumed   :thumbup:

A friend and I managed to unscrew and remove the entire top of the offending plastic stop cock by extending a special plumbing tap wrench to the depth of the line. Once the top was removed it was relatively easy to unscrew the jammed operating bits and re-assemble them. Once done the stop cock worked normally, but I really feel that plastic underground stop cocks are the pits, and best avoided. I wouldn't mind but they are not at all cheap!

So, on a roll we back filled the excavation for the new borehole sourced tap, and 'tracked' the ground with my JCB803 until reasonably firm. Raking the pea shingle back you'd not know we'd been there  :ddb:

As far as that job is concerned there is just a 'Butler Sink' and associated hose reel gubbins to move over, screw the tap to the wall . . . . AND I CAN GET ON MAKING NEW HOSES  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 04, 2020, 04:56:09 AM
It's a squally wet day here today so no outside work - what a shame I'll have to get on indoors with those hoses  :clap:

First off, before anything is cut, I need to sort out the hose lengths - they are not all the same, but I'd made the originals to be the same resulting in them sitting at odd angles - set them up and measure the difference. Turns out that the two at the top (A&B) need to be six inches longer than those at the bottom (C&D) at the Furnace Driver end due to the A&B angled fittings having to clear the C&D ones.

Then I did a forensic dismembering of one end to remind me how I put them together - it seems that:

A/ I've crimped the 70 mm CSA stripped welding cable into a tubular lug, which I've brazed to a length of 3/4" Imperial copper pipe

B/ The copper pipe is brazed into the screw end fitting

C/ The Brewers Hose is pushed on to the 3/4" copper pipe

D/ Three 1/4" Band-It clamps have been fitted

E/ All is then served with black heat shrink tubing

I have all the bits (must check my box of Band-It bits though) bar the heat shrink which is coming on Tuesday

Now I noticed that in the act of pushing the Brewers Hose onto the 3/4" scalped the innards of the pipe leaving a bit of rubber pushed down the pipe, so I must take precautions when I do it this time.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on July 04, 2020, 06:18:29 AM
Looks like there isn't a lot of room for water /coolant inside that hose...

Certainly hope the copper cleans up. It looks pretty manky...

So close and then someone orders a couple more meters of tunnel.

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 04, 2020, 07:17:56 AM
Yes that was my reaction when I first opened it up just now Russ, but I think what has happened is that manipulating it to cut the rubber has scrunched the weave of the welding cable up making it fatter and more open weave.

The new hoses will be about one metre shorter so I can lop quite a bit off each end, but I did just now go and check that when twisted back there is room, and it should be fine  :zap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on July 04, 2020, 10:33:04 AM
this could partly be the reaction of any sulphur in the rubber leaching out and attacking the copper, especially in the presence of warm water! Same reaction seen in early VIR cables, which was why they started using tinned copper wire in VIR.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 04, 2020, 12:37:00 PM
So I stripped out the cable from one old hose (the burst one, not that that matters much) and un-brazed the crimped lug. I'd hoped to do it with a propane torch but in the end had to use the big guns and dragged the O/A set out. The Portapak had a cutting torch on it but we managed!

OK time to get brave and cut some new hoses, but first I needed to check that the 16 metres had indeed been delivered. It just fitted stretching from the foundry to the end of the welding shop tied between two 1 CWT cast iron weights which not only let me check it's total length (marginally over 16 metres  :thumbup:) but also mark out the two versions of two shorter by six inches.

Time to pull the copper wire into a length of hose. That went easily using the reel of yellow fibreglass duct pulling rod.

What didn't go easily was getting the 3/4" copper pipe with the lug brazed on into the new rubber pipe -far too tight. It's the lug stopping it, so I'm going to have to re-design the fixing but that's enough for today.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 04, 2020, 04:24:33 PM
I've rather come to the conclusion that I need to do away with the crimped lug entirely, form a cup shape from the 3/4" pipe to receive the 12.25 mm diameter of the 70 mm copper wire, and directly braze the wire to the cup / pipe.

This actually is as I thought that I had done it years ago, and maybe when I open up some more 'ends' that will be revealed, but the lug on the outside of the copper tube is too big and needs to go.

I've had one of the brand new short driver cables on the workshop floor for a while - these are the ones with the wrong conical ends fitted. So I decided to butcher one to see how it was done. Turns out that basically they also have formed a cup in pipe, but it's apparently thick enough to be crimped.

So I'll be doing much the same but brazing not crimping.

The internal 19 mm bore of the pipe gives 283.5 square mm  and  12.25 mm diameter of the copper wire gives 122.7 sq mm, so the copper takes up 43% of the bore, and the water 57%

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on July 04, 2020, 06:01:30 PM
I've got to say, I like the short hose version a lot better!

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 05, 2020, 02:34:29 AM
Sadly not easy to replicate though I wish that I could.

You’ll notice that the cable is a flat plait, and the tube forming the crimp is very thick wall, neither of which I have
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 05, 2020, 10:34:20 AM
What I do happen to have though is eight 70 mm 'Butt Splice' crimps that I maybe can modify.

Objective is to modify half the butt splice to be able to encircle the 3/4" copper pipe, but leave a gap for water to emerge and use the other half to crimp the 70 mm welding cable.

So, cut half way through in the middle, slit half the length and form the resulting mangled bit of copper round a steel bar held in the vice. Then trim off corners, a bit of filing, then a run through the sand blaster.

Looks like it might work  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 05, 2020, 10:53:12 AM
So now it's a case of cleaning up the welding wire by immersion of the end in phosphoric acid followed by a good rinse, crimping the modified butt splice, cleaning any flash from the crimping to save tearing / cutting the hose as it enters, and pushing it in.

. . . and in it went - easy peasy  :clap:

The other end isn't going to be quite so easy. The rubber Brewers hose needs pulling back about five inches, gripping while the cable is gripped and cut to length before crimping on another modified butt splice brazed to the copper pipe. Once cut if the Mole Wrench gripping the cable lets go you are up the Swany as the cable will retreat back up the Brewers Hose never to be recovered  :bugeye:

Once the first crimp is made things can relax a bit - I made a total of three crimps each end to reduce the entire length of the butt splice to 'crimped diameter, and had to tidy away quite a bit of crimping flash.

After that it was relatively easy to push the fitting into the hose once the Mole Grips were released, as the compression of the hose was helping this time !

So that is one hose assembled bar the Band-It clamps and serving with heat shrink.

. . . one down three to go and at least now I have a process that seems to work  :thumbup:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 06, 2020, 10:24:37 AM
Last night I mass produced modified butt splice crimps ready for an intensive day of cable / hose making.

First cable this morning went together really easily, the 3/4" copper end terminals slipping up the Brewers Hose very easily with a drop of Hellerman cable lube.

The next cable was an absolute nightmare. When I stripped the ends ready to pull the old cable out for re-use I was met by cable end in an appalling state - really badly frayed. And pulling the bulk of the cable from the hose it wasn't in the best condition. My first reaction was that this must have been one of the original cables that I re-used, but looking at the big reel of 70 mm welding cable that I still have from all those years ago they both have the same very fine wire format wheras the other two cables had somewhat thicker strands.

No choice though - this wire cannot be re-used so I set to and stripped the insulation from four meters of welding wire off the reel, and crimped a lug on the end to pull it through the hose with the lug hole Ty-Wrapped to the eye in the end of my  6 mm fibreglass pulling rod.

Now this was exactly how I'd pulled the other wires through, but this time it was an absolute pain and put up a huge fight - no real idea why. I got to within 21 inches of the end when the Ty-Wrap (a stout THICK Ty-Wrap) snapped  :bang:

Shining a torch down the hose I could see the lug, but how to get at it? In the end I went fishing with a hook bent into the end of a 1.6 mm welding rod. First attempt got it half way before the hook straightened - second attempt was sucessful.

Next job, crimp the end fitting on and pull the cable back, pushing the fitting into the hose. First inch was fine but after that I paid dearly for every millimetre of progress despite loads of Hellerman lube on the fitting. But we got there in the end.

Then it was a case of compressing the hose back down the cable six inches, clamping with a Mole Grip, and crimping the other end on, followed by releasing the mole grip and pushing the fitting up the hose - this end wasn't too bad.

So (apart from Band-It clamping the ends and serving with heat shrink) that's three down and one to go. but I've called it a day - our first set of 'Cottage Guests' arrive shortly, we having been closed down by Covid-19 so I need to be able to meet and greet at short notice.

I did however remove the ends from the last cable, and sadly it also is the finer strands, so that's something to look forwards to tomorrow  :bugeye:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 07, 2020, 06:57:11 AM
Well I'm pleased to be able to report that the last cable wasn't as bad as it could have been. although the fine strands were a bit frayed at one end there was sufficient 'good' cable to make up the remaining assembly.

And even better - the lengths do seem to be better than previously and dress together nicely on a trial fit.

To complete the last hose, having had yesterdays major issue pulling the copper through the hose, this time I first pulled a length of 6 mm polypropylene rope through, then used that to pull the copper, rather than trying to pull directly on the rigid 6 mm fiberglass duct rod (which is hard to grip)

Having done a trial fit to check the lengths are now correct (they are!) I then flushed out each hose using mains pressure water to get rid of the last of the phosphoric acid and any debris that may have entered. The end fittings are 3/4 BSP Female with a cone internally, but using a stack of rubber tap washers formed a passable seal for this temporary exercise. Pleasingly they are all free flowing (as they should be) but when I dismantled the original hoses I found bits of hose lining jammed in the copper pipes that had been scalped out as they were pressed in. To try and avoid this I spent quite some time and trouble fairing the copper fittings, even buffing them on the wire wheel.

I'm now off to re-fresh my memory how to use the Band-It tool and do one or two test pieces !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 07, 2020, 10:52:20 AM
Reading the very scruffy and out of focus instructions that I had secreted in the Band-It box I decided that there must be better copies 'on the web'. Well, downloading one from the makers web site it told me to cut the stainless band before wrapping and tightening resulting in a loss of about 6 inches of band for every clamp - blow that for a game of soldiers - I've 24 of these to do - that's a lot of wasted stainless band :bugeye:

So I 'winged it' and in practice it's not too bad to do - with the roll of banding uncut it gets in the way of cranking the tightening handle, but that's simply cured by deflecting it with your thumb as you crank. In relatively little time all twenty four Band-It clamps were applied, and I was just thinking 'time for tea' as I still hadn't received the delivery of large heatsink tube to dress the clamps to save cuts on the sharp bits when Adrian the ParcelForce man hove up delivering my order from RS.

Tea will have to wait - eight 100 mm long slices of heatshrink were cut and shrunk over the Band-It clamps so the hose assemblies are ready to re-fit.

I'll not refit them until I've replaced the Chiller flow and return hoses with the new ones that were delivered the other day - I'd thought that I could use the existing Jubilee hose clamps but of course the new hose is much thicker wall than what is on, so that doesn't work. I had considered using Band-It clamps, but they would be permanent so I ruled that out.

. . . so more Jubilee clips on order - as I said to Adrian - See you tomorrow !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 08, 2020, 09:44:31 AM
The larger Jubilee Clips turned up just before lunch, so I've been able to replace the flow and return hoses for the Chiller with ones with a more substantial construction, with a far thicker wall.

All went well, not much coolant split, and I was able to install the newly re-made cable / hose assemblies. Again this went well with no leaks - well not entirely true, I'd left one coupler nut only hand tight so it weaped, but easily cured.

However the Furnace Driver will not go 'Ready' as coolant is not flowing in the left hand flow gauge so it's magnetic float is not lifting with flow. Now this is indicated as an 'Ext 1' fault on the control panel, which is what happened just before that hose burst.

I know that the new hose / cable assemblies all flow satisfactorily as I tested them, so there must be a blockage elsewhere. The documentation gives no indication of the plumbing so I'm going to have to 'knife and fork' it. It could be the furnace body or the furnace driver - time only will tell, but I'm now allocated to other things so that's a job for tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 08, 2020, 12:33:08 PM
Well I couldn't just leave it, I had to have another look to keep my sanity.

First thing to check - there is an input mesh / screen filter that I've never been able to get at properly due to the way the flow and return chiller pipe block access. So a bit of heavy dismantling involving my biggest Stilsons got the big connections  undone so that I could remove the whole assembly, check it and put it back in a different orientation so that it was accessible in future. Now this screen is on the input, and coolant was flowing, so unlikely to be 'the' fault but it needed looking at. Sure enough there was a fair amount of debris that was easily washed away under the tap, but it wasn't totally blocked.

Then I removed the four recently re-made hose / cables and again proved that there was free flow down them - there was.

I then turned my attention to the 'furnace body'. There are two coolant paths, "A to B" and "C  to D" - I believe that the continuous copper tube coil of the furnace has a deliberate block to coolant in it's centre, and coolant flows in at the top and bottom, (A&C) and out at the centre (B&D)

Blowing with an airline there is free passage from A to B, but C to D is blocked.

Why ? I have no idea. Perhaps a bit of debris stuck in there? Or perhaps one of the 'QD' connectors have failed? Either way it's going to have to come apart.

 . . As you can imagine this is a bit of a set back to the project - let's see what tomorrow brings
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on July 08, 2020, 02:14:59 PM
could you try a vacuum cleaner sucking in the opposite direction to the flow?  I guess you will have tried the airline both ways, but just a thought!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 08, 2020, 03:51:04 PM
Yes Phil the wet and dry vac was much in use as it also saves dumping all the coolant on the floor. All bits that could be sucked out were (behave in the back Jones Minor!)

But now I'm even more puzzled than before - I went out after supper to strip off the QD connectors - they were all free and passing my 'blow' quite happily, yet earlier those lower ones weren't :scratch: Have I dislodged something - no I don't think so as I'd have seen it come out.

I now think that the 'furnace body' has been exonerated, but it's VERY strange.

Now the output from the furnace driver has four 3/4" BSP fittings for electrical and cooling connection. A&B on the top line and B&C on the bottom. The electrical connections are a massive pair of copper straps 'B to C' and 'A to D' but coolant I think passes from A to B and C to D

It all gets VERY confusing as seeing the back of the panel where all this happens is neigh on impossible due to a mass of pipe and hoses, but one of them has a distinct kink - is the kink enough to completely block the pipe? I have (again!) no idea but that going to be my line of investigation tomorrow.

Oh joy I thought that this was nearly finished :bang:

Have a picture of my spare Furnace Body coil - you can see the two pipe connections in the middle - there is no passage between them, they connect to top and bottom threaded fittings. All irrelevent now if it's not the fault anyway
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 09, 2020, 02:21:05 PM
A long and very confusing day :

 - I was determined to precisely map out the coolant water flow from inlet manifold (from chiller) through the Furnace Driver with it's monitoring flow gauges, out to the Furnace body via the Brewers Hose / Cable assemblies, back into the Furnace driver and eventually returning to the Chiller. Now within the Furnace Driver there is an absolute tangle of hoses as not only is the Furnace Body water cooled, but the power semi-conductors and tuning capacitors have cooling plates and a radiator / absorber for the low power electronics.

Now the pipes can be seen at a distance through the left hand door, and most terminate or originate on two manifolds under a shelf at the front again through a door. By grasping a hose by inserting a 'litter picker' between the 415 volt buss bars (power isolated!) I could wiggle it, but not quite see the other end. If I could remove that shelf . . . Seven bolts later the shelf was free EXCEPT whoever built this machine bored a hole in the shalf and ran a cableform through it. Every other thing passing through the shelf has a notch so the shelf would still come out - but not this one :bang: No room to make the hole into a notch. Desperate times, so I started to plan rigging up a web cam when one of the multitude of visitors that have come today proved to be a useful extra pair of eyes  :thumbup:

So - plumbing map made and various tests performed. One necessitated pulling the pair of flow sensors slightly off the right hand panel to disconnect it's hose. It has a proprietary low profile hose clip allowing it to go through a small panel hole not much bigger than the pipe itself. It had to be replaced with a Jubilee clip, and the panel hole filed to accommodate the clip going back through !

OK - Tests showed NO blockage so I turned my attention back to the Furnace Body that I'd partially dismantled yesterday. I re-tested and proved flow through both it's water circuits, so all VERY odd - what was the previous fault as these things don't just 'go away'  :scratch:

While I had the Furnace Body apart I decided to have a close look at the Quick Disconnect fittings.  Shortly after I'd installed them years ago I became aware of a problem with their retaining ball bearings - some were corroding very badly - I assume being a fitting suitable for water that they are stainless steel. I came to the conclusion that despite the fitting having a brass body, at times the balls were carrying some of the huge currents hence the damage. My modification was to put a link of 70 mm CSA cable round the fittings, with suitable female hex pillars brazed to their adaptors.

Well of course those balls are still grotty so today I found out how to dismantle them, the intention being to order up some definitely stainless replacements. The balls that I took out were in a shocking state and accurate measurement wasn't possible. They were 'about' 1/4" or 6.35 mm but the corrosion and pitting gave readings from 6.1 to 6.6 mm! Just on the off chance I had a look in my 'might come in useful' bearing box, and for some obscure reason had a bag of 'about 1/4" ' balls - no idea what they are left over from, but they measured 6.33 mm and were magnetic so presumably not stainless. Well they fitted nicely, the QD worked like new and this confirmed me in my suspicion that the originals were 6.35 / 1/4". a bag of 100 now on order from Simply Bearing, delivery due tomorrow :thumbup:

So the plan now is to re-assemble everything, wet it up and do some flow testing (when the balls arrive)

 . . as I said, a confusing day  :hammer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on July 09, 2020, 05:50:57 PM
I dont quite follow the flow diagram. The arrows don't 'flow', and one of the 2 blue 'one way' elements has contra flow..



-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on July 09, 2020, 06:17:31 PM
Blue is cold and red is hot, to state the obvious. I think that Andrew said that the pipe pairs are A&B and C&D. Therefore you have two cold lines in and two hot  lines out.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on July 09, 2020, 06:40:33 PM
 :{
Should have enlarged it... I didn't see the 'manifold' words - there is obviously flow between the in and out manifold not shown...

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 10, 2020, 02:40:46 AM
It is very confusing looking at the actual machine which is why I wanted to do the diagram to sort it out in my head.

The manifolds connect to flow and return on the Chiller, and as Graham says the pairs to / from the furnace body are A & B, and C & D

But then additionally there are the electrical connections. B & C are strapped together as are A & D and these two connections connect  the coil of the Furnace Body, and the internal capacitor bank and form a tuned resonant 'tank' circuit

Once drawn out it’s actually pretty simple.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 10, 2020, 08:58:18 AM
The new ball bearings arrived just before lunch, so I've just stripped and rebuilt all four quick disconnects.

I'd intended to clean up the inner brass-work with a bit of steel wool, but as I'm not changing the O ring seals decided against in case a strand of the steel got trapped under the rubber.

They came apart and went back together surprisingly easily - I used a tiny smear of Vaseline in each ball housing to hold the balls - I didn't want loads as although theoretically the coolant path should not come in contact I didn't want to risk Vaseline trace in the coolant.

Intriguingly the new balls measure 6.33 mm not 6.35 - just like the bag that I already had. Now my first thought was that the difference was due to using a digital vernier guessing stick rather than a proper micrometer, but as I happened to have my metric slip gauges handy I measured a 6 mm slip and it was dead nuts on. This digital vernier has always been surprisingly accurate and I had to apologise to it for doubting it's voracity :clap:

So is the 0.02 mm a looseness for normal bearing fits  :scratch:

Sadly I can't do more this afternoon. Now lock down is lifted on holiday cottages our bookings are picking up and today is a 'double change over' with two sets of guests leaving, and two arriving, and the Covid-19 cleaning regime required is unbelievable and very time consuming.

Tomorrow should be better and I can then hopefully re-fit the Q/D's and hoses and resume testing  :med:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 11, 2020, 04:50:46 AM
A bright and early start to put it all back together for testing - and also a nice bight day to go with it  :thumbup:

First I refitted the Flow and Return pipes for the Chiller completing the coolant circuit between it and the Furnace Driver.

Then on the Furnace Body I re-reinstalled the four Quick Connects and their associated linking straps that hopefully will preserve the newly installed stainless balls. Then the four new hose / cable assemblies from Furnace Body to Furnace Driver went back on, and that's about it . .

. . . time to turn on the coolant pump and see what happens. Two sharp 'click' sounds - I know what that is, it's the Flow Gauges - their magnetic torpedoes rise with flow knocking the top of the gauge, a good sign, actually a VERY good sign as previous symptoms were no flow in the left hand  one.

Now previously the pump bypass tap had to be fairly closed, (ie higher pressure) for the flow gauges to rise, but now I can open the tap fully (ie lowest pressure) and they still work. I do remember that as the pressure was adjusted from low to high the right hand one lifted first, followed as the tap was closed further, by the left hand one. So there must have been a partial blockage for some time - symptoms were there but I hadn't recognised them.

So, in for a penny, in for a pound - put 'local power' onto the furnace driver and see if it goes PRET (ready) - oh yes. I then intended to 'ping' the Furnace Body to confirm resonance but inadvertently had the key switch in 'CHAUFFE'  (heat), and I got the characteristic 2.4 khz humming and 15 kw indicated as power consumed. Quickly pressing stop, and feeling the 2.5 mm 5 core cable from local mains luckily no harm done, but I wouldn't normally try and actually HEAT something without having it powered by the big generator - phew got away with that one.

In conclusion, there must have been a  partial blockage previously, and like a blood clot moving about the body, got to somewhere vital and killed things. My various activities over the last few days have cleared the blockage but I'm no closer to knowing where it was apart from that is was in the left hand Flow Gauge / 'C' Port / Inlet Manifold loop UNLESS that input mesh screen was the issue all along. (but if so why was the right hand flow gauge not affected as well?)

Now I've disturbed a large number of coolant connections in this investigation (17 at a quick count!) so I've left the coolant pump running while I write this and have a coffee, let's hope no leaks and no floods when I return.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on July 11, 2020, 05:51:18 AM


-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 11, 2020, 10:12:31 AM
Thanks Russ  :thumbup:

I'm glad to say, still no leaks despite having the pump running for several hours - I took to turning it off for a bit then back on reasoning that the start up is probably maximum strain - I also varied the pressure up and down. In retrospect it would have been handy to fit a pressure gauge to the coolant system to help notice any changes - maybe later.

I've spent the afternoon wrestling serpents again  :bugeye: When I fitted the long umbilical from generator to wall socket I didn't have the right sized cleats to fix it properly, so used some humongous Ty-Wraps. The proper cleats arrived several days ago but the coolant blockage took priority. I also decided to run it on the opposite side of the RSJ as it lay better there. Blooming heavy and although supposedly flexible it still has a mind of it's own.

Next job : sort out the earth bonding . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 11, 2020, 10:56:40 AM
Getting ready for a CPC (Circuit Protective Conductor) - or Earth to people of my age  making session tomorrow I though it wise to check that the tubular crimp lugs were compatible with my crimper when using the 70 mm CSA cable that I intended to use, as these are unbranded generic ones.

As the cable sheath is Black I'm heat shrinking Green / Yellow onto the ends partially encapsulating the lug as support, and I wanted to check that the 'shrink ratio' brought it down to size.

All's well so let bonding begin . . tomorrow . . I've had too much excitement today  :clap:

In actual fact these 70 mm CSA tubular crimp lugs crimp much nicer than the tubular butt splices that I used in making the hose / cable assemblies, with far less 'crimp flash' where a bit exudes and leaves a sharp fin. Same crimper, same cable.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 12, 2020, 07:08:51 AM
OK Bonding Day !

Simple really, drill a few holes, tap a few holes, crimp a few tubular lugs and shrink some heat shrink sleeving on, what could be easier :ddb:

Well very oddly my Cembre HT45  hydraulic lug crimper (of 1985 vintage) decided that today was the day to start playing up - it was somehow hydraulically locked and would neither open nor close. After a bit of an oily session on the bench dismantling its pump mechanism and its release valve, cleaning and putting it back together normal service was resumed - I'd only used it late yesterday afternoon to do that test crimp, and it was fine then - very peculiar.

So, slight delay starting, but I've decided to bond the Furnace Body, and Chiller Unit to a common point on the roof of the Furnace driver, and from there to the steel frame of the foundry building.

The very fine strands of the 70 mm CSA welding cable that I'm using make it nice and flexible, but it's a bit of a challenge to get the strands all into a crimp lug at the same time and also manipulate the crimper. I hit on the idea of compressing them with a small Ty-Wrap right at the end of the stripped length, then pushing the crimp lug on, which pushes the Ty-Wrap back towards the un-stripped cable sheath. When sufficient is in to be stable I then cut the sacrificial Ty-Wrap off pushing the strands fully into the lug. Unconventional, but it works for me !

So everything in the actual foundry building is now bonded together with ridiculously heavy cross section cable - better bigger than smaller  :clap:

Yet to do is bond the Generator, and the frames of the four buildings to each other.

I should perhaps explain:

A/ My Welding Shop is a steel framed 'lean to' added to the South side of my main workshop, and is made of bolted together RSJ's and angle iron, fitted to flying brackets welded to the steel frame of the main workshop.

B/ My Foundry is a steel framed building added onto the west end of my Welding Shop, and although again of RSJ and Angle Iron construction is fully welded but as far as I can tell is 'free standing' as far as the steelwork is concerned, and just joined by the roof so no real electrical connection between the two.

C/ The 'Stable' where my big generator sits is another 'lean to' added to the North side of the main workshop, and is made from RSJ uprights and  rafters as three frames, but they are held apart by timber purlins and free standing so again no electrical connection

So bonding this lot together gets a bit complicated. Certainly I will bond the generator frame to the adjacent RSJ frame of the stable, and try and get a cable through the wall to bond them both to the steel work of the main workshop. And I will try and bond the foundry, main workshop and welding shop frames together where they all come together at a corner. But I don't think I'm going to go as far as bonding all the stable frames together - not fully decided - we'll see!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 12, 2020, 12:27:08 PM
This afternoon, despite interruptions (*) I managed to bond the Foundry steel work to that of the Welding Shop and Main Workshop - this went quite smoothly when I was able to do it !

Then I turned my attention to the big generator. Its main earth terminal is inside the control box down at nearly floor level, but I wanted to bring the cable in from the top through a gland, so that it more directly could run to the nearest RSJ frame. This was a bit complicated as it involved removing the safety covers, the perspex one in particular is a pain to get in and out (I know - I made it, it's my fault  :bang:)

I still have to bond the two RSJ frames in the stable to both the generator and the steel work of the main workshop but that's a job for tomorrow - I've had enough!

(* a friend presented me with a bolt - "I'd like one almost like that but a different thread"  Well the bolt he had brought was 1/2 UNC and apparently it screwed in a bit but was loose. Now this is off a (possibly) Japanese grey import digger so the thread could be almost anything! It's a critical application as it's holding the main hydraulic pump so best get it right. Pump currently held by one bolt and is too heavy for him to get back in place single handed if removed for measurement. In the end I turned him a tapered piece of delrin and told him to force screw it in, back it out and bring it back for inspection - might work  :scratch:  )

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 13, 2020, 03:24:01 AM
Another fabulous bright and sunny day, so I was up with the lark, and had finished the last of the bonding between the building frameworks by 8 am  :thumbup:

. . . perhaps now I can get on with something a bit more interesting and less neck cricking  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 15, 2020, 05:32:04 AM
Continuing the theme of trying to enhance the safety in the foundry before I start using it in earnest yesterday I admitted defeat with a small but persistent roof leak. Only happens when wind in a particular direction, but the drip was dripping directly onto (and through  :bugeye:) a double 13 amp socket used for the roller shutter electrics. Amazingly it's never tripped the 30 mA RCD over the years. So if I can't cure the drip, live with it and move the socket  :ddb:

. . so I did - actually I added a spur to the foundry ring main (in a sheltered position !) as previously it was fed from the shutter circuit for the main workshop roller shutter and now is off the local sub-main so more logical.

Towards the end of the day I ventured down the 'blind alley' that is between our boundary and the welding shop to try and find the safety cover that originally bolted onto the right hand side of the Furnace Driver and covered the exposed output connections. I found it hidden under an inverted plastic water tank that I'd used as air trunking on top of the old refrigerated water chiller that failed. Being of welded sheet aluminium construction it had survived the years pretty well but was absolutely FULL of wild life. Snails, slugs, spiders and goodness knows what! I roughly brushed it clean(ish) and left it in the foundry over night to dry off for inspection.

So this morning after further brushing and blowing out time for inspection. I decided to scrub it with a strong citric acid solution - I'd thought perhaps caustic soda that works well on aluminium, but the citric acid won as it's nicer stuff to work with.

Apart from some pitting corrosion where I had previously stuck a Danger sign it's actually scrubbed up pretty well. A good hosing to rinse the citric acid off, followed by an air blast and an hour in the morning sun and it was ready to bolt on . .

. . .so I did.

A new warning sign ordered, and when fitted will cover those corrosion pits nicely  :clap:

Meanwhile I've devised a way of plumbing in a means of measuring the coolant pressure when operating - bits on order - hopefully this will help to give an early warning of any more blockages  :scratch:

Incidentally, up the 'Blind Alley' I came across a large Air Receiver that I used as a reservoir in the loft of my last workshop and is now redundant - If it is of any use to anyone it's 'free to collector' - you can just see it on the picture.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on July 16, 2020, 03:06:00 AM
One day, in the future, when a new civilisation rises from the ashes of this one, your place is going to prove absolutely fascinating to archeologists!  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 16, 2020, 12:27:43 PM
. . . and I'll still be here Ade plodding along through my list of jobs  :lol:


Today I installed the coolant system pressure gauge. This required a modest bit of engineering - turn a 28 mm slug of stainless steel, through drill it and bore and tap 1/4 BSP to accept the rear entry gauge fitting. Simple really and only cost me the tip of a centre drill - not too keen on stainless!

The bit I made sits in the branch of a 28 mm Tee compression fitting that I inserted in the vertical pipe run from the pump at a height that meant I could work without draining down the tank.

The book calls for a pressure between 3 and 5 bar. The pressure switch in the Furnace Driver Inlet Manifold clicks over at 2.8 bar, and the Grundfos pump can produce a maximum of 4 bar. So I set the pump bypass tap to give a system pressure of 3.5 bar - comfortably within the spec.

. . . no leaks so far  :thumbup:

(and yes, I now HAVE cut the 'glycerine pip' on the gauge to allow for expansion !)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on July 16, 2020, 01:16:41 PM
Looks like it's coming along nicely!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 16, 2020, 01:32:06 PM
Ready when you are Matthew  :thumbup:

I took delivery of the replacement fireproof cladding for the box on the inverting furnace body yesterday but haven't had a chance to experiment cutting it. The stuff I used before was 6 mm tile backing board and this is 'Aquapanel'  so similar stuff but 12.7 mm / 1/2" thick. When I've cut the panels to size I intend to slather them in sodium silicate solution to firm up the cut edges which tend to be rather powdery. They say that, like plasterboard, you can scribe one side and crack to size, but with the thinner stuff certainly you end up with one side rather 'undefined' - I think I'll experiment with an angle grinder.

This stuff contains a load of cement, so any saw won't be much good after a few cuts, but a diamond angle grinder blade might have better luck :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on July 16, 2020, 02:59:19 PM
The way things are, I can't see crossing the Channel before Christmas! Looking forward to seeing this in the flesh!

Cheers, Matthew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on July 17, 2020, 04:12:19 PM
I was just thinking Andrew, with all the monitoring you have fitted to the project you won't have time to watch the crucible  :doh:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 17, 2020, 06:25:38 PM
Well it got used this afternoon - cottage guests had left and Penny was away so an opportunity to fire it up without any complaints of generator noise  :ddb:

At first I had a bit of a panic. I'd been doing my testing on local mains when fitting the pressure gauge and all was fine. Swapped over to the heavy cable connection,  started the generator up (OK it IS a bit noisy, but a good sound!) but nothing was happening what so ever at the furnace driver - panic . . is wasn't until a few minutes of poking and prodding had elapsed that I realised that when I was fitting the earth bonding in the generator, I'd flipped off it's internal isolator.

A flick of it's lever and all was well with the world!

The very first unsuccessful melt of some copper pipe where the pipes ended up with slits in that I'd done when everything was put back together a few weeks back was tossed on top of a lump of brass as a 'starter pool' resulting in a lump of maybe 4 kgs of very coppery brass after not much more than 5 minutes heating.

It was just another trial dumped into an inverted spare crucible. In the picture the coppery one is the one I did today (brass plus copper scrap) and the brassy one is the other half of the same brass ingot but without added copper.

Now I need to start up the mould making side of things. I'm going to have a try at 'lost PLA' casting using forms 3D printed

I did manage to stick on the Danger notice on the safety guard, and order up some replacement  foundry boots from Zoro Tools. Proper ones with steel toe caps and insoles and heavy leather spats to keep molten splashes from spoiling my socks! What I thought was a modest price at £42 including postage - not many places stock boots that fit my size 13 hooves! The ones I used to use are long lost long ago !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete W. on July 19, 2020, 08:53:16 AM
Hi there, Andrew,

I quote: 'Proper ones with steel toe caps and insoles and heavy leather spats to keep molten splashes from spoiling my socks!'

I seem to remember reading somewhere that the spats are more to cover the lace-holes of your boots - they're more splash-retaining than your socks and the boots are slow to remove!  What material is used for the RN's flash-resistant clothing?  Is it cotton?  If so, maybe cotton socks should be the order of the day.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 19, 2020, 09:52:35 AM
Pete, they've not arrived yet but I think that these ones have quick release fixings for both the boot and it's spat.

As I'm sure you realise reference to my socks was tongue in cheek !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 19, 2020, 02:56:02 PM
OOPS - wrong picture - try again !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 19, 2020, 04:26:45 PM
I started drawing up a model in Fusion 360 of a label for our 'Bore Hole Taps' - it's 25 mm x 75 mm and needs refining as the detail is going to be too fine for the silver sand I am using with sodium silicate. The idea is to use 'lost PLA' - ie encase the model in silver sand with 4% sodium silicate mixed in, set it with Carbon Di-Oxide, then burn the PLA out in a pottery kiln set to 650 Centigrade. More work needed.

But as an adjunct to this I cut some slices off that big lump of coppery brass that I produced on Friday, and to my surprise found that it was hugely porous. Now I've had this with aluminium castings where hydrogen gets entrapped and forms bubbles but not with brass. I strongly suspect that the metal was far too hot, and the bubbles are zinc vapour. Hard to prove but I'll make a conscious effort next time to pour at a lower temperature.

It's all a (re) learning curve !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on July 19, 2020, 06:35:47 PM
Interesting I wouldn’t have thought about the temperature vs zinc gas bubble formation.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: pycoed on July 20, 2020, 05:51:04 AM
Look on the bright side, Andrew: you've just invented Oilite : :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on July 20, 2020, 09:57:12 AM
ded.

But as an adjunct to this I cut some slices off that big lump of coppery brass that I produced on Friday, and to my surprise found that it was hugely porous. Now I've had this with aluminium castings where hydrogen gets entrapped and forms bubbles but not with brass. I strongly suspect that the metal was far too hot, and the bubbles are zinc vapour. Hard to prove but I'll make a conscious effort next time to pour at a lower temperature.

It's all a (re) learning curve !

Hi Andrew,

It may be just air bubbles due to your casting in an open crucible.

Have a look at Olfoundryman
&t=0s

He's casting in Al, but his sprue and risers are worth looking at!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 20, 2020, 04:49:54 PM
Very informative and certainly food for thought Matthew - thanks for the link.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 26, 2020, 05:58:08 AM
Time to tackle the 'Tilting' furnace body - if you remember I'd previously used domestic plumbing flexible hoses that had adversely reacted with the hydraulic oil in the 'air over oil' set up.

So first drain the remaining oil - most had already been squirted out when the hose fitting burst a month ago!

Then strip off the old fittings and pipes.

Then do a 'dry fit' of the stainless hydraulic fittings that I'd bought to check that I'd got the right quantities and genders.

. . . all a bit of a rush as I've got a chap due in 6 minutes to discuss (fencing of the agricultural type - not epees !)

Have a few pictures:
 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 26, 2020, 11:30:04 AM
So it was an afternoon of crimping:

First dig out the Parker crimping machine with it's hydraulic hand pump and a set of crimping dies for the 1/4" hose that I'm using. This size is a rather an arbitrary choice - I hope that I will get sufficient flow remembering that although it's using hydraulic oil, the pressure is only 'airline pressure' at about 100 psi. But I already had the hose and fittings and only had to buy the fixed adapters so that swayed me. Time only will tell . . .

Now the sequence is:

a/ Measure the application and cut a length of hydraulic hose to suit.

b/ Fit a ferrule over each end ensuring that it's fully home by tapping with a mallet.

c/ Insert the appropriate barbed fitting (straight or 90 degrees in my case).

d/ Crimp one end

e/ In the case of two 90 degree fittings adjust angular alignment 'on the job' and mark up the hose, ferrule and fitting.

f/ Crimp the other end

All quite easy, but short hoses with both ends a 90 degree fitting need careful alignment as this hose doesn't rotate to accommodate errors!

The crimper consists of a hydraulic cylinder that, using a 'gathering plate' forces a set of dies down a tapered hole over a set of 'teeth' to close down round the ferrule and squash it firmly, uniformly, and permanently round the hose and barbed fitting.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 26, 2020, 11:35:45 AM
Then it was a case of measuring up and assembling the various hoses on the machine, but in 'free space' as I've not yet decided how I'm going to clip them. I want to hold them as far from metal drips as possible, and maybe bend up 'drip shields' to go over them where possible.

However, until I can get it back into the 'able to tilt' state it's not easy to predict what will foul what as the crucible rises up - I may even have to adjust some hose lengths.

So now all the hoses are made and loose fitted and I'll wait until tomorrow to fill it up with oil as the adapter fittings have been 'Loctited'  and that needs to go off
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 27, 2020, 05:40:25 AM
By this morning the Loctite pipe seal had had ages to 'go off' so I tightened all the cone seating pipe nuts and did a 'dry trial' ie no oil in the reservoir.

I'm pleased to be able to report that it worked splendidly - it sort of questions whether I need the 'air over oil' set up, but I expect with a full crucible I probably do - certainly that was my conclusion back in 2006 when I installed it.

So now I need to sort out pipe clips and some sort of sheet metal splash guards for the pipes. I'd rather assumed that the 'Munson Clips' that I'd previously used were a right off after bad handling in storage, but it turned out that only one 'foot' was broken, and amazingly I had one in my box of 'might be useful' bits (probably originating from the 2006 build!). I've temporarily put them back on, but they hold the pipes too far off the chassis and will be replaced, probably with rubber lined steel 'P clips'.

The arrangement of the Quick Disconnects is as a straight line of four QD's and foolishly I've never marked up what is what. However I dug out a photo of the inside when I commissioned it in 2006 which will let me work it out.

Among the pictures were a pair that reminded me of an issue that I'd had - the copper pipe was barely able to carry sufficient current even with water flowing though, and I'd had to parallel  up 70 mm CSA welding cable to give it a hand with all those pesky electrons! There was also a picture showing where I'd managed to fuse some of that cable - I hate to think what current that was carrying,but I can't remember the circumstances that caused it. (well it IS 14 years ago!)

So I'm now off to order up a few pipe clips !

Have a video of it working:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 28, 2020, 06:34:19 AM
Today's task: make up a set of copper commoning links for the Raydyne complete with flying leads of the 70 mm CSA welding cable so that  changing from one furnace body to the other is simplified, as the links on the Inverting Body are a bit of a pain to remove.

OK - need copper bar - no suitable copper bar in stock - squash some 28 mm copper pipe in the Epco 60 ton press and use that! So two six inch lengths were cut off, flattened, marked out, drilled, profiled, and cleaned up in phosphoric acid. I then prepared two short 'flying leads of the heavy welding cable with lugs on the end crimped so as to be at 90 degrees to each other to avoid a twist when in situ.

All then assembled and finished - well not quite as I'll replace the steel nuts and bolts with brass ones when they are to hand.

Meanwhile I dismantled the stainless plumbing arrangement that had previously been used and rescued most of the fittings for the 'may come in useful' box.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 28, 2020, 12:22:36 PM
I've just re-filled the reservoir with 32 weight hydraulic oil - no idea what I'd used before - unlikely to have been a hydraulic oil as I had no hydraulic powered machines then.

Using just compressed air, a full tilt was 6 seconds, which is too fast. Putting 3 litres of 32 weight hydraulic oil in the reservoir (cylinders total swept volume = 2.8 litres) it takes about 30 seconds which is too slow - I'd like 15 seconds for a smooth controlled pour. Perhaps I can cut the oil with something to reduce the viscosity?

A bit of 'googling' suggests that the oil in a J&S 540 head with the plain bearings is either ISO 10 weight or 32 weight cut 10% with paraffin.

So what can I use to 'cut' hydraulic oil? Paraffin perhaps - suggestions welcomed !



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 28, 2020, 03:04:24 PM
As I don't have any paraffin oil, and getting it is a pain, I used Red Diesel. Google tells me that their viscosity is much the same. So I drew off 1 litre with a stomach feeding  syringe (sorry next years lambs!) and replaced it with 1 litre of Red Diesel.

The result: the 30 second rise time is now down to 22 seconds and the current mixture is 1/3 Red Diesel and 2/3 32 weight hydraulic oil - so that is definite progress.

Tomorrow I'll adjust the ratio again to maybe 50:50 - or even less, as if I go too far I do still have the flow rate valves to adjust - they are fully open at the moment. Need some hydraulic oil in there for cylinder lubrication, but it's not a high stress application really.

When the aerated hydraulic oil that I drew off has settled it can go in the dumper truck, as it leaks like a sieve!


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on July 28, 2020, 05:40:00 PM
Hi Andrew,

If I remember correctly, your red diesel has a dissolved, wax ( it's the element that solidifies when diesel freezes) in it which is there to lubricate the injector pump when used as fuel in a diesel engine. So please, correct me if I'm wrong, in my opinion, lubrication is not  a problem!

Cheers, Matthew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on July 29, 2020, 03:26:14 AM
I started thinking this Yesterday, but I have first hand experience on normal hydraulic olis of VG32 and VH46 viscosity. The company chooses Iso VG 32 over 95% of the thime, then VG 46 is used only when ambient temperature is significantly higher. On lower end of the ambient temperature tank heater kicks in and the hydraulic oil heats due to work it performs.

I wonder if the normal iso VG 32 oil would perform fine in the working temperature?

Most normal hydraulic oils are pretty much normal mineral oils that have some additives to prevent foaming, help filtering, disolve water (water is one of the biggest problem in modern hydraulics, you don't want it to steam on elevated temperature of cavitate at uner pressure, or rust) and usully a litte amount of EP additives to help lubrication.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 29, 2020, 03:38:48 AM
Matthew I think that you are entirely correct - diesel HAS to have some lubricity otherwise the injector pump would sieze up, and this is why 'certain travelling folk' add oil to stolen central heating oils as it's "slipperyness" is much less.

Pekka, the oil 'should' remain at ambient temperatures when in use (barring disasters  :bugeye:) so it's viscosity isn't going to decrease sadly. All my farming equipment uses ISO32 as it's rare that we get very hot here.

This morning I drained down the oil / red diesel mixture and re-filled with neat red diesel. Timing the rise (pour time)  it is now at 18 seconds which is about acceptable but I'd still prefer to be able to set it a bit faster.

Obviously this is as fast as I'm going to get without either:

a/ Raising system pressure (a pain as it uses my air distribution system common to many machines)

b/ Increasing hose bore

c/ Finding an incompressable medium more fluid than Red Diesel (unlikely)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on July 29, 2020, 09:50:33 AM
OK. Because that system has no pumps, tanks, filters etc. there is no real reason to use hydraulic oil. Unless there is no special seal/hose/componenet reason you could go down to 5W straight/mineral transmission oil. Multigrade engine oils has allready many (unnecessay on this one) additives, and the car 5W-something oils actually have higher viscosity than VG32 hydraulic oil at room temperature.

https://www.engineeringtoolbox.com/iso-vg-grade-d_1206.html

There noteworthy thing is viscosity at +40C, different grades are defined very different ways. They don't compare in simple relationship.

There are very low viscosity oils, but they are a bit special and have their own issues. Hard to get lower than that mineral base oils...needs to check too many variables....hydraulic system might work with PAO-base oils too. But where to get them in cosumer market? And they suck at fire resistance :doh:


https://www.machinerylubrication.com/Read/31106/polyalphaolefin-pao-lubricants

Interesting problem.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 29, 2020, 10:33:00 AM
Yes it has all sorts of ramifications Pekka. For instance the exhaust port silencer now puts out quite a bit of diesel vapour as the cylinders are discharged, so much so that I've put a plastic cup under it to catch the drips.

Obviously is not viable when actually pouring molten metals instead of testing. I am tempted to go back to 'straight air' and drain the reservoir again. I originally went to 'air over oil' as  I was getting rather too much bounce with just air, but maybe if I throttle it back it'll be OK? -

. . . I'll experiment if time permits tomorrow.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on July 29, 2020, 11:57:35 AM
Dnot wishing to teach grany etc. etc.
 If operating speed is an issue whether pneumatic or hydraulic, cant you use speed restrictors to increase the operating time?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: PekkaNF on July 29, 2020, 12:10:08 PM
Air tends to be bouncier than incompressive liquid...I understand the merit of the air-over-liquid, liquid throttless nicer.

I wonder if a simple viscous damper would work in addition of the orginal air system? But it involves additional mounting poins, a little calculation and experiment. Also it probably does not not work equally well with min/max loads.

I never used waterbased hydraulics...apparently algae growth is a problen there, glycol coolat based might work, but that one too needs special seals. I would use the original system with air and add separate damper cylinder with liquid throttling or viscous damper.

We used once a system that had two hydraulic cylinders to perform same "swing" because the weight sifted "over the centre" of the gravity. Simplest form was to laod one cylinder (one side) with a constat pressure to prevent load from sifting direction at the middle of the stroke (that would produce a major jolt). There are load lowering valves etc...but each solution has it's own set of problems.

I have seen very well dampened pneumatic systems, but they had servos....
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 29, 2020, 01:28:47 PM
Dnot wishing to teach grany etc. etc.
 If operating speed is an issue whether pneumatic or hydraulic, cant you use speed restrictors to increase the operating time?

John, If you look 'up thread' you'll see that I have two one way valves (up & down) each followed by a flow restrictor
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 29, 2020, 01:39:11 PM
Pekka, to be frank I doubt that any practical to use liquid, including water, is any less viscous than diesel, which is pretty free flowing.

Using a liquid as the operating medium has the advantage that it is theoretically incompressable hence no bounce.

BUT Raydne designed it to operate on air - so I'll see if I can temporarily revert to just air and play with the flow restrictors
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on July 29, 2020, 02:01:15 PM
Ahh...sorry Andrew, missed that bit... :Doh:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 30, 2020, 05:13:38 AM
Pay attention John  :lol:

So I decided to revert to 'air only' tilting on the Raydyne furnace body as originally designed. I wasn't happy having the oil fumes in close proximity to the molten metal and the speed of tilting was a bit slow. It definitely was less bouncy, but at an unacceptable price in terms of other parameters.

I could put the oil system back relatively easily, but to plumb for 'air only' necessitated physically removing the reservoir (a cut down CO2 cylinder!) as the plumbing for the flow restrictors was screwed into a tapping in the cylinder wall. Just one pipe to remove and a somewhat longer one to make and it's done.

With the restrictors set full bore it now raises in 4 seconds and comes crashing down - just cracking them open gives about a 10 second rise and probably I could extend that a bit with careful setting of the valve. There is no longer a delay in raising the crucible, as that previously was caused by it taking time to pressurise the air over the oil in the  reservoir.

It'll take a while for the remains of the oil / diesel mix to flush out of the pipes and cylinders - already afer only a few cycles the exhaust 'air' is getting a lot cleaner and less fumy.

Meanwhile the more suitable pipe clips have arrived so I'll try and fit those today - not sure my back is up to all the bending down so I may try raising it to waist level with the forklift.



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on July 30, 2020, 06:00:03 AM
Hi Andrew,
Are your molds going to be attached to the body?It would seem to me that you'll need to be able to adjust the speed on the fly to be able to have a full sprue to avoid taking in air. How did that work out in the past?

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 30, 2020, 07:00:23 AM
No Matthew, with the tilting furnace body you either fill a ladle and pour from that, or arrange your moulds at a suitable height to pour direct, in which case it's a matter of raising the tilt sufficiently for the metal to start flowing, and reversing the lever to start descending to stop the flow when the sprue is full.

I managed to clamp the hoses - I can't say I'm over happy with the way they lay - flipping awkward stiff things !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 31, 2020, 09:52:25 AM
Gentlemen (and Ladies if present!)  I have a dilemma  :bugeye:

I've been wanting to power up the Radyne and use it, but at the moment I'm completely confused as to it's connections. I'm SURE that I used it previously after installing the new crucible, but the way it's internal plumbing is illustrated in the picture below it CANNOT have worked I think.

I had expected the terminals to map A, B, C, D from left to right and indeed on one photo the extreme right hand pipe has a D on it

As the photo clearly shows, Terminals 1 & 2 are connected ELECTRICALLY as are Terminals 3 & 4 - you can see the blooming great copper horizontal strap between them.

Now the actual induction coil  has a deliberate blockage where the nylon reinforced hoses from Terminals 2 & 3 come together.

So coolant entering 1 can ONLY exit by 2 (and vice versa) and coolant entering by 4 can ONLY exit by 3 (and vice versa)

BUT the electrically commoned terminals on the furnace driver are pairs "A & D" and  "B & C" with coolant flowing out of "B & C" and returning on "A & D"

So if "A & C" on the driver map to  "1 & 4" so that the top and bottom of the induction coil are connected correctly coolant has to come out of  "2 & 3"

On the tilting furnace body the terminals that are commoned at it's end correspond to the commoned ones at the furnace driver.

If I screw this up it could be curtains for the driver electronics  :bugeye:

So if any of you have been able to follow my confused ramblings - please go logically through this and tell me where I've gone wrong - or have I gone wrong - or did I plumb it up wrongly back in 2006 ? (I can see that if I swapped over the two internal nylon reinforced hoses within the Raydyne it might make more sense :scratch:)

. . . my head hurts . . . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 01, 2020, 05:43:29 AM
So in the absence of other suggestions, this morning I opened up the back of the Radyne Tilter, and lo and behold it seems that I'd done a second re-plumbing eliminating the welding cable current reinforcement by using heavier walled pipe. (It looks like I've used 3/4" air con pipe tailed with 15 mm) However the issue remains in that if connected up it would put a direct electrical short across the Furnace Driver - not good.

I 'think' by interchanging the nylon reinforced pipes I have a solution that 'should' work - certainly now no direct short across the driver !

I was able just to uncouple the threaded fittings and move the pipes, but I'm not happy with their lengths as they are touching the copper driver pipes, but I'm out of stock of 15 mm bore nylon pipe - they'll do for test purposes until I can get some more.

So now "A & D" are electrically commoned at both the Driver and Crucible ends, as are "B & C" but the order of connections on the base of the furnace body are a bit illogical reading "C B D A" left to right

I do remember having standard metal Jubilee Clips getting hot in the field of the coil and melting pipes and sure enough the ones on the outer connections of the nylon hoses are nylon clips to avoid this problem, but oddly the ones on the other end of these pipes are standard metal ones
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on August 01, 2020, 05:57:53 AM
Hi Andrew

I'd just spent 10 minutes trying to understand this when you posted your latest update.  I think I agree with where you've got to.  Clearly the electrical connections have to take priority and that means the piping wouldn't have worked unless there was something strange going on at the connections on the side of the coil.  The other variable I was trying to get my head around was whether there was any significance to the direction of coolant flow - for example to keep the nylon pipes cooler than the copper ones - but I would hope that they would be kept sufficiently cool for that not to be a problem.

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 01, 2020, 06:23:13 AM
Russell, now you see why my head hurt - thanks for your ten minutes - much appreciated !!!

One 'advantage' of this flow system is that cold coolant enters both sections of the coil at their respective bottom coils and leaves at their highest coil thus circulation is aided by thermal / gravity effects. Whether this is at all significant is debatable though!

Much search for 15 mm bore nylon reinforced pipe so far has drawn a blank. 13 mm no problem. 16 mm no problem. 15 mm no sign  :bang:

I am conscious that access to the centre connections on the coil is severely limited so struggling a pipe on would be an issue - the other end access is easy so no problem.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: charadam on August 01, 2020, 09:01:44 AM
Any use?


https://www.hoseshop.net/reinforced-pvc-hose/pvc-reinforced-hose-18mm-od-x-13mm-12-i-d-15-mtr
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 01, 2020, 10:37:41 AM
That's the sort  of stuff, but sadly they also only offer 13 & 16 mm o/d  :scratch:

I've found a place on eBay that stocks 14 mm so I've ordered a bit (1 metre) of that, and also a metre of their 16 mm. Probably the 14 mm will be OK when warmed up a  bit, but as I said before access is tricky. (The adjacent side panel does bolt on, but it also holds the pivot that the whole thing swings on so not easy to remove)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on August 01, 2020, 11:25:09 AM
The 14mm hose will easily go onto a 15mm barb if you poke it up an exhaust pipe for half a minute. I've done this many times on site especially in winter.

Engine has to be running :)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on August 01, 2020, 01:03:03 PM
Andrew,

If your object was to give us head aches, you  succeeded! I couldn't see it from your explanation and diagram! Seems to me to be break out the ohm meter time! Good luck with the hoses! It's so near now!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 01, 2020, 02:12:17 PM
Matthew I knew that it was a difficult concept to get across - I struggled writing it coherently - but basically if connected so that the coolant flowed correctly it would have put a dead short across the driver output and if connected so the electrical drive was correct, no coolant would flow (I think!)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on August 01, 2020, 03:42:38 PM
Andrew,

I sort of understood your worry, I would have needed to see more to under stand it easily! The ohm meter is your friend!

All the best! Matthew.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 02, 2020, 04:34:57 AM
No point in procrastinating any further - get it connected up and try it !

. . . . so I did, but firstly I connected up the low power local mains feed - can't really start the big generator as the cottages are full of guests - and made sure all was working on the inverting furnace body before disconnecting it. Yes - all OK - so I removed the four hose / cable assemblies. Proved continuity where it should be, and connected up the Tilting body.

First test - does the coolant flow? Argh - NO  :bang: Oh heck NOW what's up? Intensive investigation and what do I find - those pair of flexible pipes that go to the centre of the coil do a little jig round the back and come out REVERSED ! So what appears to be the top of the lower half of the coil is in fact the bottom of the upper coil, and vice versa. So Russell you pretty well put your finger on the problem in you post where you said "unless there was something strange going on at the connections on the side of the coil".

This has been the issue all along - the pipes I moved were in fact in the correct places - there WASN'T a problem - it was actually correct in the first place.

OK, get over it, swap the pipes back, prove coolant flow - YES flowing in both circuits.

So, next test - put (low) power on the driver, let it come ready - yes it does - 'ping' the furnace body - whoopee yes we get a good result at 2.25 kHz - as expected a lower frequency than the other body as this one is a physically bigger coil so presumably markedly different inductance.

Now until I can get the place to myself and hence fire up the big generator that's about as far as I can go for the time being apart from tidying up and sorting out the safety shields etc for the pipe / cable assemblies.

. . . phew it seems to be working . . . thank goodness . . . it took long enough !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on August 02, 2020, 05:13:34 AM
 :clap: :clap: :clap: :clap:

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: edward on August 03, 2020, 04:53:37 AM
Andrew, I've enjoyed immensely following this trouble shooting and you getting to where you are now. Its the same with all your threads for me, the detail, analysis and skill in solving problems is brilliant to see.

I have a question, to which the answer might well be'because I can/want to/its there', but what will you do with it once its up and running? Do you do casting a some kind of business, for fun or just enjoy fixing up old machinery.

Its not a criticism at all, I'm just curious :) I get asked a similar type of question as to why if I have 4 bikes I need to build myself a 5th one, to which the answer is that I like bikes!

P

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 03, 2020, 05:21:01 AM
Edward, it's a bit like the 'why do you climb mountains' question - it's not logical  but I enjoy it - that's fixing problems by the way not climbing mountains!

No there is no commercial thing here, and I really no longer need to make castings, but at my last place I'd set my self up and was determined to re-create the facilities that I'd lost in moving. It's only taken 13 years  :bugeye:

It all began when, many many years ago I was driving home from work through Peckham in SE London and spotted something 'interesting' in the far corner of a Taxi repair garage. After several days of rubber necking to see what it was I stopped to have a good look. It turned out to be a "Hoverair Hoverhawke" three engined hover craft in 'basket case' condition. Chap said that I could have it for peanuts if I took it away.

Back then I had no workshop or machine tools. Well it ended up on the back lawn on tressels needing comprehensive repair to parts of the box section chassis, and the engines and propellers re-assembling and missing parts sourced. One missing part was an aluminium casting shaped a bit like a pudding basin, that bolted onto an engine flywheel and coupled it to the propeller. This got me involved with a local (to me then) foundry and a machine shop, and this kindled my interest in casting and machining.

The rest is history - my workshop has developed from that project over the decades. I got the hovercraft back together and hovering on the lawn - it was pretty big with a three man enclosed cabin - but I never finished the cosmetics. I'd put a bid on an entire redundant computer network infrastructure in the city and my bid won. The kit was in a warehouse in Kew at a vast rent so had to be moved pronto into my dining room (floor to over the picture rail), three removal lorry fulls - about 7 tons ! and the powers that be put her foot down and said she wanted either the lawn or the dining room back - most unreasonable.

I sold the Hoverhawke to a chap in Essex, but now it is in the hovercraft museum:

 https://www.hovercraft-museum.org/collections/




The network kit - that financed buying my next house and ultimately the farm where we are today  :clap:

Now I'm sitting here willing my cottage guests to go out for the day so I can start up the big genny - I've sort of decided that if they'e not gone out by 11:00 I'm doing it anyway !!!!!!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 03, 2020, 06:26:47 AM
The 11:00 deadline came and went so I fired up the 110 kva generator and did a simple 'bar heating' exercise to put a bit of load on the connections and wiring - all seems well  :thumbup:

The same bit of 16 mm mild steel bar that I'd used before was raised quickly to glowing point - a matter of a couple of minutes or there abouts.

There must be some sort of power limiting algorithm running on the furnace microprocessor - it 'topped out' at  59 kW this time - I suspect that it is based on the charge in the crucible. I must experiment when I have the place to myself with greater and lesser charges and see when the yellow 'limit' light comes on as I turn up the power.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: edward on August 03, 2020, 07:36:34 AM
Thanks Andrew - I love your threads and the forensic detail you go in to with your repairs.

There is no better reason for doing something than because you love it. I've been building bike wheels recently, mostly because I wanted to learn the skill rather than any actual need to do it, and when it all comes together its just so satisfying.

Your Hovercraft video gave me flashbacks to a trip I had across the channel on one of the big Hoverspeed craft with the venture Scouts when I was in my teens. It was really rough, half our unit were up the front enjoying crashing over the waves and the other half back aft somewhere, filling a lot of those paper bags with the contents of their guts. Luckily I've always had pretty good sea legs :)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on August 03, 2020, 07:39:41 AM
Now I'm sitting here willing my cottage guests to go out for the day so I can start up the big genny - I've sort of decided that if they'e not gone out by 11:00 I'm doing it anyway !!!!!!!

Seems like a plan  :clap:
John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 03, 2020, 08:27:08 AM
Well they've actually all gone out now - one couple were still there when I did the previous run but they were indoors so may not even have heard anything - after all it was over in five minutes - that's the good thing with induction heating.

SO - let's do a second run with more mass in the crucible and see what happens. I added a 550 mm length of 33 mm hexagonal mild steel bar to the 16 mm round that was already in it, fired up Big Bertha and again ran to glowing heat - just a few minutes. Limit came on this time at 70 kW / 147 amps (had been 59 kW  / 122 amps previously)

I'm now thinking maybe the electronics is measuring the resonant circuit peak voltage and putting a limit on that - it's not entirely consistent but first run the voltage was  646 v at limit, this run it was 639 v. Need much more data I think.

Anyway I learnt two three lessons in this exercise.

a/ Driver goes into limit at different powers depending on charge in crucible

b/ Don't worry TOO much about the noise - it's much less at distance and I'm up close.

c/ And DON'T poke your tape measure in the crucible to measure a bar length - even when everything is OFF it's still hot enough to remove the paint !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on August 03, 2020, 10:22:04 AM

c/ And DON'T poke your tape measure in the crucible to measure a bar length - even when everything is OFF it's still hot enough to remove the paint !

So you are human after all!  :D
Would also echo Edward's earlier comments about the thread, 'twill be a sad day when it ends.
Pete
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 03, 2020, 10:45:11 AM
Quote
So you are human after all!  :D

Pete

Only too human I'm afraid Pete - you've seen a few cock ups in this thread surely !

And there was I thinking I was boring the pants off you all with my ramblings

I've been looking in detail at what circuit diagrams I have for this beast - the power electronics is comprehensively covered, but the control electronics is treated as a 'black box'. It's a single large PCB called a Saphyr Monocarte with loads of  microprocessor support chips and both digital and analog circuitry. Fortunately the manual labels the various connections to it, and I've managed to deduce that it IS monitoring the voltage on the resonant circuit (Internal massive capacitors and external crucible coil) through a step down transformer, so presumably that is the 'Voltage' displayed on the control panel, and it looks as though it has a limit set at around 646 volts as that value features in several of my pictures when 'at limit' independent of which furnace body is connected. The 'Current' displayed is the 3 phase input current and fairly closely corresponds to the value that the diesel generator indicates.

. . . it's all a learning exercise !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on August 03, 2020, 11:20:28 AM
 :D :) :D :) :D :) :D :)

Great stuff!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: kayzed1 on August 03, 2020, 03:03:41 PM
Just imagine how many shillings you would need to feed the old meter to run that :zap: :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 03, 2020, 03:21:55 PM
Well it wouldn't be TOO bad.  Including the standing charge we are paying about 18 pence per KWH. So running at 100 KW for an hour would be £18. BUT the heats I did today both were only minutes long. Say 10 minutes to do something useful, so £18 / 6 = £3

Not cheap but not earth shatteringly expensive. I've no idea yet a comparable figure is for running my generator  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 05, 2020, 06:21:40 AM
Before I start using the foundry in earnest there's quite a bit of sorting out needed - stuff has just been piled up all over the place to let me get on getting the furnace working - well now it does so time to start the sorting.

Just outside the foundry sliding door, in the welding shop, were two 1 metre wide shelving units that historically have held electrical installation materials, rolls of conduit wire, adaptable boxes,  isolator switches - you know - the stuff that accumulates and is too good to throw out as undoubtedly it WILL be needed. Over the past weeks I've been re-deploying it elsewhere - largely successfully but you always end up with stuff with no home  :bang:

In the clear out I found a brand new emergency 'maintained light' unit - sensible to install it in the foundry if it still works - it's NiCd 4 AH 2.4 volt battery was down to 1 volt so it's now on charge but 'the jury is out' whether it will actually work.

The idea was to remove the two shelving units, put a back on one of them to stop it racking and also stop bits falling off at the back, and put it in the foundry for crucible, pattern, moisture meter etc storage where the 18" square clothing locker currently is where the PPE kit lives. This necessitated moving a foundry bench (that still has a load of Mansfield sand in it) sideways six inches, a feat accomplished with help from a friend yesterday.

So today I looked at the pile of sheet metal for a suitable backing sheet, and found a full 8 x 4 sheet of galvanised expanded mesh left over from building the Plasma Table extraction system - a result as I'm unlikely to need the mesh in future and it saves a sheet of useful Zintec for other needs.

I'd intended to lay the shelving unit down with the mesh on top, and cut it with an angle grinder, but then I remembered an electric hand held shear that I'd bought some years ago but found to be pretty puny. Rated for 1.2 mm it really struggled, but it ate this mesh like nobodies business  :ddb: It was the inability of this shear to really work 1.2 mm steel that prompted me to get a guillotine so I shouldn't really bear a grudge!

OK back fitted, shelving unit installed, quite a bit of foundry related 'stuff' put on it AND I now have a two metre length of wall space in the welding shop that has allowed me to push the Linisher, the Corner Notcher and the Band saw up to the wall out of the way - all of a sudden movement is far easier!

The second surplus shelving unit has found a temporary home in the Tractor Shed - it needs fixing to something to stop in racking though.

I just need now to find somewhere for the clothing locker - the corner by the roller shutter would be perfect apart from the roof leak above it that I don't seem to be able to cure  :bang:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 05, 2020, 04:00:08 PM
So, after a suitable time interval I checked the NiCd battery and amazingly it's come up to a fully charged state :thumbup:

So I plugged the main inverter PCB back in connecting the battery and mains. The fluorescent light tube lit and the LED was OFF - it should be the other way round !

I then made a close examination of the PCB, which only has four transistors and two diodes plus a bridge rectifier - getting it lit up with a torch to read type numbers (I'd intended to replace the lot!) I noticed what initially looked like a scratch in the PCB but actually was a crack. It's cheepo paxolin not fiberglass so not very strong. I identified no less than six breaks in copper tracks (remember this is new never used!). Scraping the conformal coating off the tracks I made solder 'bridges' over the damage and tried again plugging it in. Result - it now works as it should  :clap:

Now solder bridges are not going to be very reliable, and if I decide to use it I'll put wire links in to replace the tracks. I seem to remember I bought a 'job lot' years back when I was equipping the main workshop - they were genuinely unused but one was declared as not working so it must have been this one.

Barely worth repairing as I can buy a new one for £25, but quite satisfying  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on August 06, 2020, 02:29:14 AM
"Barely worth repairing."

BARELY WORTH REPAIRING?   :bugeye:

Wash your mouth out man  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 05:19:54 AM
Well Graham it's two and a half hours into a three hour 'run test' and doing well - 2.4 volt battery down to 2.23 volts.

So you'll be pleased to hear that I WILL put proper repair links on the PCB along with a bit of epoxy glue, re-assemble it and stick it over the sliding door entrance to the foundry - pictures will follow later !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on August 06, 2020, 05:28:29 AM
 :beer:  :D
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on August 06, 2020, 05:51:20 AM
Amazing it worked at all with that damage...

The score so far as best I can remember...

Buy and restore 100kva generator
Buy, restore and sell trailer for generator
Clear and renovate outbuilding for generator
Diagnose faulty  chiller
Replace chiller with total loss heat exchanger
Find, test, restore bore hole
Install bore pump and pump house
Replumb irrigation system to allow use of bore water
Replace coolant hoses
Restore air over hydraulics
Repair emergency light
Install earth bonding between multiple outbuildings
Clear room for furnace
Build external storage cage for O/A cylinder storage (part of clearing)
Reinforce shelving
Install 3phase 'domestic' supply for 'ping'
Repaired cold saw
Provide enormous entertainment and education for the unwashed

No doubt some I have forgotten.

I'm hoping this is not the end, but maybe you have something even better in store...


-russ
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 07:44:50 AM
Gosh Russ, you at least have been reading my posts  :clap:

. . . scary isn't it - just to play at melting a bit of brass !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 08:37:57 AM
This 'non-maintained' (meaning it's not on all the time) emergency light is rated to last 3 hours. My test showed it to actually have a run time of 2 hours 50 minutes. If I can't get out of the foundry in less than 2 hours 50 minutes I have other problems not solved by lighting  :clap:

So I went ahead and did the repairs. Firstly I cut a strip of good quality fiberglass printed circuit board and super glued it across the crack to try and stop further movement. Then I put wire 'salvage' links between the nearest component pads either side of the breaks. There was one exception, where the track is deliberately very thin to act as a fuse - in this case I scraped away the solder mask and soldered directly to the track. All salvage links were then fixed down with a few drops of super glue.

I seem to remember when I worked at Ferranti on the process control computers boards were allowed to have up to five salvage links, but they had to be identified with a short length of red sleeving to distinguish them from 'modification links' - you were allowed loads of mod links! Mind you these were complex multi-layer boards with oodles of ic's on board.

Having proved it still worked I then mounted it over the sliding door entrance to the foundry running the lead to a spare 13 amp socket in a dual that also feeds the roller shutter.

Seems to work OK :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on August 06, 2020, 12:00:42 PM
Ferranti computers?....
Argus GD700 by chance?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 12:21:10 PM
Argus 400, 500, 600, 700. first one I worked on (Wiggins Teape #5 paper mill in Dartford) was an Argus 400 with Argus 100 input output racks !

My era was mostly A500's & A700's in many variants and applications but I did have an Argus 600 in the office that I'd programmed as a digital clock - about all it was good for though Barclay's Bank used to run payroll on them at Juxon House in St Pauls Churchyard - a hideous architectural monstrosity next to the Cathedral.

We did everything from the 4 minute warning (Russian Hoards over the horizon, deep RAF radar bunkers) to mixing dough for Ginger Biscuits (McVitie's Waxlow Road Harlsden)  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on August 06, 2020, 03:04:51 PM
I was working at a gas terminal in Barrow-in-Furness during the 80's where they had a 700 series supervisory system. I had the job of site acceptance testing and commissioning of the control system....quite strange how the operating system was loaded and run from discs...
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 03:46:30 PM
We had quite a bit of kit on gas and oil rigs. Your Barrow one would be part of the Morcombe Bay field. I had staff on rigs there but loads of other places as well from Bacton in Norfolk to Port Harcourt in Nigeria as well as Orkney & Shetland with monitoring at Dyce near the airport.

Glad those days are over - my phone never stopped ringing day & night  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: John Rudd on August 06, 2020, 04:15:31 PM
I'm glad those days are gone too, the Easington terminal that I moved to after, had a Taylor system, again with Hawke disc drives.....Great when they had a head crash!! not!!    Especially at 2-3 am ...and got called to site to repair/rebuild....
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 06, 2020, 04:35:48 PM
Disks were a major step forwards. Mobil's Coryton refinery had two Argus 500's with Burroughs 2 megabyte fast disk storage - 20" platter, 100 heads each side flying on compressed air but these were fast memory access not for loading - that was from a paper taper reader.

I remember one night having to change the disk enclosure (a three man lift due to weight) and the reload took (I calculated) 14.1 MILES of paper tape. because it was from Fortran source code that had to be compiled on the way in  :bugeye:

I HAND WOUND every inch of that tape - it was a long night !

(An other enclosure change on a hush hush site involved taking the platter the length of the M6 under military escort  so that they were able to witness it being cut to pieces with oxy-acetylene - a bit extreme, but it did contain the NATO fleet deployment details !)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on August 07, 2020, 03:19:41 AM
(An other enclosure change on a hush hush site involved taking the platter the length of the M6 under military escort  so that they were able to witness it being cut to pieces with oxy-acetylene - a bit extreme, but it did contain the NATO fleet deployment details !)

It would have been just as effective, surely, to attach the platter to the back of the landrover on a piece of rope and drag it behind? By the time you reached the M6 it would have been ground into dust.... much shorter trip!

I was lucky (unlucky?) enough to miss those early days of computing; by the time I entered the fray, desktop PCs were normal, albeit not entirely across the organisation. A little prior to that, whilst at North Staffs. Polyversity (it actually changed to a "University" in the middle of my course), I got some experience with a DEC VAX machine, which left me with an enduring soft spot for VMS. To the point I currently have 6 MicroVAXes..... As much as I'd like an 8800, I don't think I've got suitable storage space for it!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on August 07, 2020, 06:16:53 AM
Ade there were a myriad of ways that we could have ensured total destruction of the data, ranging from strong magnets, to acids to dissolve the nickle plate (magnetic layer) off the brass platter, but when you are dealing with these official bodies, and their 'expert' has made a plan they won't budge !

The easiest way would have been to force a 'head crash' on all 200 heads by over pressuring the flying mechanism . . .but no . . they probably wanted a nice day out . . but all they got was Wythenshawe in Manchester :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on August 07, 2020, 07:31:53 AM
Quote from: AdeV
  I got some experience with a DEC VAX machine, which left me with an enduring soft spot for VMS. To the point I currently have 6 MicroVAXes..... As much as I'd like an 8800, I don't think I've got suitable storage space for it!

One of my recent projects was migrating some mission critical apps on openVms from alpha hardware to an alpha emulator running on Linux running on vmware esx running on x64 hardware. One of the apps was originally running on Burroughs A series, ported to Vax.



-russ
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 08, 2020, 04:22:58 PM
Progress on the foundry has been held up by 'other stuff', but also by a persistent roof leak many have tried to cure :(

The foundry is an 'addition building' to the welding shop which is an 'addition building' and the leak is where the three roofs join.

Initial problem is that the foundry fibre cement roof has been laid to too shallow a pitch (4 - 4.5 degrees - 'big six' should be at least 5 degrees) so water was tracking back up the corrugations and entering at joins - this has been solved by painting with a patent fibre loaded roof sealant.

However, the 'welding shop roof' tucks under the overhang of the 'main workshop roof' then the foundry roof abuts this but the levels prevented the roofer properly flashing the junction with (say) sheet lead. Joins have been 'reinforcing mesh' taped and again painted with the gunge and I really thought that the problem was solved until the wind came from a different direction and again we got water in  :bang:

This was traced to water entering the ridge of the main workshop and running down inside to the join. This was hopefully sealed a few days back but we've had no rain since.

I've just been out to inspect as we've had light drizzle for an hour or so, and darn me there is moisture on the floor - but now I'm confused as to whether perhaps this is not a leak but the floor sweating :scratch: No sign of water where the previous ingress was.

To sort out in my mind the layout of the three roofs I went onto Goggle to try and expand the view and much to my amusement I find where the leak is was some very odd looking object. It took me some while to realise that it is one of the many roofers 'caught in the act' of trying to fix the leak  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 09, 2020, 02:48:10 PM
We've just had a bit of 'significant' rain in the last hour, and this shows that the roof IS still leaking and there's no point in trying to convince myself that it was the floor sweating  :(

I'm very tempted to try injecting squirty expanding foam in large quantities from below into the voids that must exits up between the three roofs, after all there have been many attempts to stop it coming in from above by people far more qualified than me.

Can it make things worse - answers on a post card please . . . . :scratch:



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 09, 2020, 03:40:31 PM
Two observations Andrew. It is usually possible, and indeed usually far easier to make things worse than it is to make them better! Trying to fix a leak from underneath doesn't work in my experience. I think you or someone else (preferably you and someone else) need to go up on crawling boards and have a look. Now is not the time of year, but if needs must you CAN paint Chromapol on to a wet roof, the water wicks up through it and it does work, even though it sound unlikely! If the big 6 is in decent condition, and it looks like it is leaking at one place only, you need to start at the top where the roofs meet, and work your way down, removing all the moss and dirt, and any previous attempts to repair the leak, and you need to look carefully. We had a recent leak on a built up felt flat roof, which dripped into the kitchen quite consistently, and I eventually found a tiny crack in the felt, which I scraped out and filled with Chromapol, even though I was very dubious that I had actually found the leak, but it cured it! Nothing more depressing than a leaking roof, I wish I lived closer I would be up and fix it!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 09, 2020, 04:07:52 PM
I think the count is now 5 (or may be 6 now) experienced roofers have attacked this without success Phil and every seam, join and overlap have been coated in several applications of Chromopol as have bolt heads etc.

Moss has been removed - the sheets are only about 10 /12 years old, and much crawling about on scaffold boards has been done !

Careful application of a hose pipe gradually working up the roof did at first reveal a weak spot, initially one fixing bolt head lowish down and then right on the ridge / apex of the workshop where water tracked down under the facia / barge board so some twenty foot from where the water emerged. Since then nothing shows up until it rains. This evening there wasn't even significant wind !

. . . but thanks for the thoughts and anyway a bit of googling has revealed that none of the expanding foams create fully closed cell product - the best seem to be 70% closed  cell so will become waterlogged.

. . . . foamed cement perhaps  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on November 09, 2020, 05:25:37 PM
I wonder about flexseal anyone ever try it?
https://www.amazon.ca/s?k=flexseal&gclid=Cj0KCQiA7qP9BRCLARIsABDaZzjeyWuUOBDwmENH5bi0lONmaIxBqYzBqtxcHFNipUq6Get9wsl0ADcaAru0EALw_wcB&hvadid=208225827327&hvdev=c&hvlocphy=9001314&hvnetw=g&hvqmt=e&hvrand=5745184742793747989&hvtargid=kwd-300327936467&hydadcr=8147_9617955&tag=googcana-20&ref=pd_sl_16u0hohih7_e
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 09, 2020, 08:21:51 PM
My experience is probably similar to yours Andrew so I know I'm not saying something new, but ..... a persistent problem leak is often located far removed from where it appears in the building. Water leaks in, hits an internal horizontal member, and then travels a distance along that before falling off. If it hits another horizontal surface, it can then travel in another direction.

If 5 or 6 professional people have worked on a particular area and the leak is still occurring, then most likely the leak is not where it is thought to be. Maybe if you think about it definitely not being there, some other possibility will occur to you.

One other suggestion, which may not be practical, but if there's some way of tracing the water, you might get a clue about where it's entering. If you could spray with a hose a small patch of some colored water on different sections of roof (or different adjoining roofs) the color of the leaked water may give an indication of where the leak is coming from.

That's about all I could think of anyway. I do agree that trying to stop a leak from inside is probably not the best way. If the leak appears to be stopped from some expanding foam, there still can be water buildup inside -- and constant damp is destructive to structure. Or the leak may travel out of that patched area, and appear somewhere else.

Tough situation, especially with cold weather coming on. Fingers crossed, I hope you find the source.  :beer:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Peter Cordell on November 09, 2020, 10:51:55 PM
Could water coloring pigments/tracing dyes help narrow down the search or thermal camera should show cool damp patches?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on November 10, 2020, 02:59:58 PM
You can buy tracer dye for this purpose. https://www.screwfix.com/p/monument-tools-flourescein-drain-dye-133g/31595 (https://www.screwfix.com/p/monument-tools-flourescein-drain-dye-133g/31595)

Could get messy though and would take some methodical working to avoid inconclusive results.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 10, 2020, 03:04:33 PM
My (possibly crackpot) idea at the moment is to rig a tarpaulin over the apex of the main workshop (where the last leak was found) and observe what happens in the following rain. If nothing comes in I can reduce the size of the tarpaulin and watch and see again.

I fear that dyes and. colorings will get awfully confusing very quickly.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on November 10, 2020, 03:27:59 PM
Is there any product that is visible with a black light?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 10, 2020, 03:30:45 PM
Good idea Andrew, the reason I am still repairing roofes (Rooves?) is that I have no faith in the so called Professionals. I asked a local roofer to put another top sheet on my workshop roof, he has a good reputation, but a pair of "subbies" arrived and did the job when I was away, took them a day, and only cost a grand.............and was as rough as a bulls lug, which is why it got box profile sheets with insulation as soon as I could afford it. Can you take some pics when you are up there?
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on November 11, 2020, 05:44:23 AM
Roofs  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 11, 2020, 11:17:42 AM
My (possibly crackpot) idea at the moment is to rig a tarpaulin over the apex of the main workshop (where the last leak was found) and observe what happens in the following rain. If nothing comes in I can reduce the size of the tarpaulin and watch and see again.

Seems like a good plan to me. :dremel:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 11, 2020, 12:16:55 PM
Implementing it won't be easy though Steve. Both flanks of the main workshop have 'lean too' buildings attached that have shallow pitch roofs, so fixing ropes isn't going to be straight forward. And the apex / end wall / ridge where the one leak was found is where the 415 volt three phase supply enters the building.

I'm wondering if sand bags tied to ropes tied to tarpaulins might work with the bags (of necessity) resting on the slopes of the workshop roof. But we do get some pretty fierce winds at times and tarpaulin = sail = potential for a disaster   (there is an 11,000 volt three phase line not very far behind the workshop on this side) :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on November 11, 2020, 01:33:18 PM
potential for a disaster   (there is an 11,000 volt three phase line not very far behind the workshop on this side) :bugeye:

Hmmm - where you see potential disaster, I see potential opportunity  :lol: :zap: :zap: :zap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 11, 2020, 01:57:31 PM
Ade, I'm ahead of you. When I'd just applied for a 415v 3 phase connection when we moved here, some yellow coated men came knocking on the door wanting to know who owned the land, as they wanted a way leave to re-cable the 11 kV to 415 transformer and the (at that time) bare overhead 415 v 3P cables.

Having just been quoted £7,500 to string a wire from that very transformer to my barn to give me 3 phase in the workshop, I assured them that the land owner would, I was certain, grant a way leave if he got his feed installed F.O.C. And that's how I got a 160 amp per phase 415 volt three phase supply in the workshop  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 11, 2020, 03:35:21 PM
Is it feasible to staple the tarp at it's top edge along a long 2 by 4 (while on the ground)?  Then maybe roll it a couple turns to make sure of the connection. and then clamp that timber at it's ends to the edge of the roof at either end? I really have no idea how wide these roofs are --- also no good mental picture of what the roofs look like/sizes, etc., so forgive the dumb suggestion (if it is).

If that's do-able at all, you could do the same with the bottom edge of the tarp. That might hold it better in the wind. You could add additional clamped cross battens after (not stapled) between for more security.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 11, 2020, 04:10:40 PM
Steve if you look at the Google Earth picture that I posted above, the main workshop is about 40 foot square and it’s flanking lean too’s are about 40 x 20 from memory, so it’s a substantial area of roof, but only the end with the foundry abutting the welding shop is the problem despite at least one leak coming from the ridge of the main workshop. 

Sadly clamping is off the menu as the roof edges at the ends are trimmed by 90 degree L sections of fibre cement  with no overhang and of course the lower edges project over the lean too’s with a very small gap that has been foam sealed.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 17, 2020, 11:05:21 AM
In the continuing exercise to try and waterproof the foundry building I've decided to re-make all the joins and laps in the roof using a re-enforcing mesh fibreglass tape. Using the same Cromopol compound that has fibres mixed in, the idea is to paint a layer on, embed the mesh, then put another layer on top. Two rolls of 150 mm wide mesh on order, and scaffold boards hoisted ready this morning onto the roof for when it arrives.

Meanwhile I've turned my attention to the roller shutter door. I know that rain has been penetrating under it. Unfortunately the concrete floor slab slopes marginally the wrong way INTO the building at one corner (remember this was laid as a yard not a floor!) resulting in the rubber base seal of the shutter having a harder job to do. To counter this I had hand laid a cement raised kerb for the shutter to close onto, but even so the seal wasn't very good.

I noticed that the rubber of the seal had gone hard over the years, and it's single 'lip' in places had folded under and taken on a 'set' not to return. So this morning a replacement arrived - this time with multiple lips and of course softer rubber.

It just clips on to the 75 mm wide bottom bar of the shutter so I fitted it this morning. It still fails the 'hose test'  playing a garden hose onto the shutter but this is pretty severe and it is still sealing to an imperfect threshold.

It's my intention to remove the hand laid kerb with a Kango back to base concrete, and mould a dead horizontal but somewhat wider one (maybe 10 inches) whose top will  slope outwards maybe by an inch, and when this is fully set, hand form shallow ramps inside and out from sharp sand and cement so that wheeled 'things' can still move around. This will form a smooth surface for the shutter seal and make any rain that penetrates flow back outside. All a  bit of a fag, but it should work.

One issue is that water hitting the shutter currently is entering the top of the seal where it grips the 75 mm bar, and flowing along inside the seal and out at the ends, but I think that this can be solved by using a brush full of the roofing gunge at the metal / seal joint.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 17, 2020, 11:29:15 AM
Water, never where you want it when you want it, and always where you don't.

"It's darn slippery stuff, I tell you," he said, staring out the window at his now emptied 3000 gallon cistern, surrounded by a world of mud, more rain due in the afternoon, with a wood splitter and 3 more cords of wood to split in the middle of it.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 06:18:12 AM
OK I've determined that water is getting in in three places  :bugeye:

A/ Under and round the roller shutter:

    The old bottom seal was replaced yesterday but the seal to shutter joint leaked. Last night I pryed back the outer upper lip, put roof seal gunge  under
     it, re-seated the seal then put more gunge in the angle where they join, and am pretty sure that is now water tight.

    The threshold 'kerb' that it comes down onto is uneven leaving a 1/2" gap in places - I'd intended to chop it out (it's soft sand and cement with added
    PVA) and re-instate it in sharp sand and cement but I've changed my mind - I'll still hack it out, but I've ordered a commercial moulded rubber
    threshold that incorporates a step as a dam and is bonded down with Everbuild Stixall that by all accounts seems amazing stuff and even can be
    installed under  water (It may have to!)

B/ Where the foundry corrugated sheet roof meets the bargeboard above the roller shutter.

    We tried sealing this junction with 'eaves closer' foam inserts and roofing gunge - it improved things but wasn't a full cure. It is this junction that I tried
    (and failed!) to improve today. The re-inforcing mesh arrived so I was up on the roof while the weather was good trying to install it. Sadly the mesh
     hasn't got the 'give' to  sink into the corrugations and still remain on the bargeboard - it just spans across. I had to pull off what I had done for a re-
    think. It did however successfully let me seal two gaping bargeboard joints.

C/ This is what I think of as the 'original leak' as it was the first that I was aware of.

     Water is running down the outermost corrugation of the main workshop roof and straight into the foundry. Theoretically water should never enter this
     corrugation as it is covered by the upper face of the bargeboard, and the sheet to bargeboard has already been taped and sealed as has the moulded
     ridge   capping. This corrugation emerges into the foundry due to the history of the three buildings being built sequentially and the roof being (lets be
     polite!)   imperfectly designed. I think that this leak is going to prove the hardest to cure.
     
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: modeng200023 on November 19, 2020, 07:21:04 AM
Well Andrew, there is one thing that comes out of your roof capers.
You are getting plenty of exercise  :clap:

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 07:59:17 AM
Yes John, but not the sort that I like . . .  roofs are NOT my natural element . . oh and by the way that Cromapol is amazingly slippery if you accidentally put a hand or foot on it . . AMHIK . .  :bugeye:

I think the way forward with that particular joint with the corrugations is a squirt of expanding foam into each 'rabbit hole' and when set trim it off vertically and paint a thick layer of Cromapol over the foam.

. . . but I'm open to suggestions . . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 19, 2020, 09:23:48 AM
The roofing should lap over the barge board, and there should be an overhang past the barge board. That's the basic problem. Right now It forms wells which are actually the lowest points on your roof. The lowest point should have been the drip edge.

Water will sit in those wells, and no matter how you plug the roof/board juncture with goo and foam, that will eventually crack under exposure and freezing and thawing of those wells, and wick water in.

Around here in Vermont any damp juncture that has spray foam inside is sooner or later discovered by ants, who think it's an ideal nesting medium and excavate tunnels in it. It's similar to decaying wood which is easier to carve and more insulative than new wood. This is the downfall of some modern foam panel house construction methods here as well. Any sealing imperfections are eventually discovered by ants. In fact many embody insect repellents for that reason.

I think the only good solution is to eliminate those wells and cover the barge board so there's a continuing slope past the wall to a drip edge. What comes to mind, other than re-roofing properly, is somehow continuing the roof line over the BBoard. I can't think of any ideal easy way to do that. A hesitant suggestion from me would be to try to fill in for a short distance up the roof with overlapping lengths of new corrugated roofing.

Unfortunately this properly should tuck underneath the old roofing, and then overlap the BBoard. I suppose you could try to lap it over both, but then you are presented with having to seal the edge where the old and new roofing lap. Still this is a much smaller thickness joint than those wells, and the reinforcing mesh and goo would likely have a better chance of surviving, than they would in the present location. The other advantage would be the possibility of extending the roofing past the BB for a proper overhang. The overhang might help with your threshold water splash ingress as well
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 09:31:23 AM
No Steve you've got it upside down. If only it was that easy ! This is the high point of the slope of the roof, The barge boards are designed to fit over the sheets, but obviously not at the low end where the gutter is !

So DPD delivered the threshold strip just now so my job for tomorrow (weather permitting - it's just started raining again) is to hack off the old threshold, make sure that the underlying concrete is a smooth and dust free as reasonably possible and glue the new threshold into place.

Obviously delivered rolled up but I've unrolled it in a heated workshop to give it a chance to relax into an approximately flat state prior to laying.



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 19, 2020, 09:44:19 AM
Okay got it, impossible to tell from the photos.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 09:52:28 AM
Steve I'm adding another annotated view of the roofs involved to clarify what I mean. The label 'Top Barge Board' is where I was working today - this is the top (upper) part of the foundry roof and the fall is away from this point.

The label 'Main Workshop Side Bargeboard (Sealed)' has the one corrugation of that roof that penetrates the foundry and is leaking. Goodness only knows how rain is getting into it.

By the way - the foundry is entirely of non-combustible construction so no acrylic sheets I think


(And I see that man is STILL on the roof  :lol:)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 19, 2020, 09:55:03 AM
I guess the top "barge board" is what we would call the roof cap here in the States. Seems short for that, particularly on a low pitched roof. Any chance of putting a second wider cap over it?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 19, 2020, 09:57:11 AM
aaah we're cross posting...... I'll shut up for awhile...
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on November 19, 2020, 10:01:24 AM
I've used that rubbery threshold under / behind my roller door and it's been totally successful. I also used that Stixall "hybrid" adhesive and it hasn't failed anywhere. The clever part was looking at the ends where it met the pillars and sealing that too, to avoid water creeping round.

This stopped the puddles forming inside the doorway when we had heavy rain (the concrete floor isn't level and slopes the wrong way).
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 10:08:03 AM
For a double pitched roof (like the main workshop) we have moulded ridge pieces in the fibre cement material that fit neatly into the corrugations each side of the ridge (visible in one of the pictures  - photo #7 of post #546) - I'm not aware of a barge board equivalent ie flat on one branch of the L and corrugations on the  other - anyway one isn't fitted but it would be a good solution if it exists and not impossible to retro-fit.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on November 19, 2020, 12:53:24 PM
Cast one in place?  Yeah I know........:loco:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 19, 2020, 01:03:06 PM
A bit of googling shows me that they ARE available in 1 metre lengths, ie one roof sheet widths at about £20 each so about £100 for what I need. They are called Eaves Corrugation Closers.

I think the foam and gunge wins at the moment  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on November 20, 2020, 07:29:48 AM
Could you use wide sheet metal flashing? So it extends well over the edge and well back onto the corrugations.
Notch around the corrugations so it sits quite close.

Of course the angles may have done my head in and I'm missing the point...

I think there is also a lead replacement sheet material that can be dressed into the profile.



-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 20, 2020, 07:46:53 AM
Well Russ the plan for today was first to squirt some expanding foam to fill the 'upper bargeboard to corrugations' gaps, and while it was expanding and going hard start to remove the old sand and cement threshold ready for the new rubber one to be bonded down. By this time the plan was to trim back the expanding foam at 45 degrees with a sharp knife and liberally coat it with the Cromapol roof gunge.

Well all plans have to be flexible when weather is considered ! It was minus 1.5 degrees C here this morning and there was ice on the barge board so no way I was venturing onto it, and the foam needs 5 degrees to properly work (but doesn't mind the water - in fact it needs it to cure)

So things got reversed. I started by chopping out the old threshold using my Kango fitted with a 'Clay Spade'. It has come off remarkably cleanly despite a liberal coat of PVA on the concrete before I laid it. After a good clean up I glued the rubber threshold in place weighting it down where it was trying to curl up. I can't just lower the roller shutter, as if any of the glue oozes out I'd end up with the threshold and the roller shutter seal glued together. It will have to stay partly open for probably 24 hours to give the 'Stixall' a decent chance of curing as the temperatures are at the lower end of it's range.

Then having cleared away the sand and cement from the threshold I could get on squirting the expanding foam. In the event it was possible to do it all off a ladder leaning over the bargeboard.

I'll probably leave the foam until tomorrow before I trim it to shape and slap the Cromapol on, but thankfully that too can be done off the ladder.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on November 20, 2020, 09:06:52 AM
Fingers crossed it all woks out this time, Andrew.

PVA is not recommended for use in wet environments. SBR is the new wonder adhesive since it's an acrylic, so not water-based.

PVA still remains water soluble even after it's set.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on November 20, 2020, 12:11:46 PM
That Stixall is bloody marvellous stuff. Usually described as an adhesive sealant, available in black, white and clear. The clear really is crystal glass clear, which has its uses and the white stuff can be used where you'd previously have used acetoxy silicone bathroom sealant. It sticks to just about anything and sets to a rubbery texture. I've used it to hold shower panels in place, glued the new bath to the wall, skirting boards in place, even bonded a 2m x 1.4m glass shower panel in place. You can get a really neat finish using either those finishing tools or just skill(!) followed by a quick swipe of the finger with dilute washing liquid.
https://www.toolstation.com/stixall-adhesive-sealant-290ml/p69243 (https://www.toolstation.com/stixall-adhesive-sealant-290ml/p69243)

It's like many resins and adhesives ie a sod to clean off your hands. Dunno if you've see this stuff but it's marvellous. It's ester-based, so reasonably kind on the skin but very effective at its job. Doesn't take much and you can mix it with Swarfega or liquid soap. Worth having one handy. https://www.arco.co.uk/products/2750400 (https://www.arco.co.uk/products/2750400)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 20, 2020, 12:40:20 PM
I have high hopes of it, but I'm pushing my luck temperature wise. It's lower 'application temperature' is 5 degrees C. The concrete that I'm gluing to was 6 degrees C when I put it down - it's now 7 degrees and the forecast is for 10 degrees overnight (seems a bit high - we are in a frost hollow) and their quoted setting time for a 1 mm thickness is 24 hours at 23 degrees C.

It is still tacky  six hours after laying so if this is still the case in the morning I'll try and arrange a mild heat warming tunnel over it with polythene sheeting and a fan heater on low.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 21, 2020, 05:40:23 AM
Well good to it's word the forecast was correct for once and it was at least 10 degrees overnight, resulting in the Stixall having at least partially cured. Even the bits that have oozed out as biggish lumps are pretty solid so I felt happy to remove the weights and inspect. The outer edge is absolutely fine, the inner edge has one or two ruckles that will need a bit of attention when I'm sealing the ends of the threshold to the frame of the shutter.

I then went back up the ladder and trimmed the expanding foam on the upper barge board to approximately 45 degrees and gave it a good slathering of Cromapol fibre filled roof sealant.

As I'm writing this my extra tube of Stixall has just been delivered by the postman (postwoman actually, Steves on holiday!) so I can carry on with the sealing, but in practice I think it best to give the first application longer to fully cure, and anyway rain is threatening.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 21, 2020, 12:28:50 PM
That looks good Andrew, you can't do with water dripping into the foundry!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 21, 2020, 12:57:58 PM
I’m getting a bit neurotic about this Phil!

But water,  molten metal and high voltages at high frequency don’t bode well  :bugeye:

I don’t think I’m out of the woods just yet but this should solve two of the three water sources when I’ve fully sealed the ends of the threshold strip to the shutter frame.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 22, 2020, 01:16:02 PM
seeing your three phase overheads reminded me of a visit to a farm many years ago where an ancient old boy in plus fours showed us a problem with his 3 phase mill mixer unit, when it failed to start, and growled, we immediately sussed it was off a phase, but the old boy said "nay lad, thats summat else" grabbed a long peice of wood, wandered outside and began to poke at the line taps on the overheads! when the guy I was with shouted at him to stop, he said "Why its areet as long as't woods dry, otherwise appen thoo'l get a tickle off'n it!" Needless to say we fixed the problem (star delta coil failed on an old Memota side handle starter) and also refitted all the line taps so he didnt get fried!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 22, 2020, 01:40:43 PM
Those overheads feed my 160 amp per phase supply - I reckon they'll get mighty warm at 160 amps - the feeds down the barn wall to the current transformer metering gizzmo are only 6 mm aluminium but they insisted on huge copper meter tails - can't remember the specifics but it was more than 50 mm csa !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 22, 2020, 02:56:07 PM
Well Andrew, if the aluminium evaporates at least its their problem, not yours!
Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 22, 2020, 03:35:08 PM
Wooden clad barn wall soaked in creosote - I think it could become my problem  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 23, 2020, 01:13:54 PM
 :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 03, 2020, 07:33:08 AM
Leak developments  :ddb:

The other day it was raining but not pouring down, and water was coming in as usual. I went up the ladder and just stared at things to see if any clues jumped out. I was surprised at how much water was running down the face of the main workshop bargeboard.

Cement fibre barge board sits  on a wooden barge board. Water is running down the face of the cement barge board and tracking into the gap between the two. As the wooden barge board penetrates the foundry (due to the sequence of construction of the three buildings) this water is at least one of my leaks.

An application of Cromapol has reduced the problem to just a few drips today but not eliminated it as the gap is too large for it to bridge. When the rain stops I'll squirt some expanding foam in, trim it off and give another coat of Cromapol.

. . . watch this space !



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 03, 2020, 10:36:02 AM
I feel your pain, Andrew!  :bang:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 03, 2020, 10:37:50 AM
Well it's all looking pretty promising  :ddb:

It's been raining solidly for the last five hours - not hugely heavily but definitely 'significantly' and I just have one little damp patch. Now it may be that the winds are favourable (hard to tell) but I think I am actually on to the last leg of curing this roof leak  :thumbup:

And even the Roller Shutter seal is working with no rain ingress  - by heck it'll be a big relief if at long last I can move on to actually USING the foundry!

When it all dries up I'll do the squirty foam packing of the barge board gap and slap more Cromapol on . . .and you never know . . .I may be able to move the shelves back under where the leak has been, set out the furnace bodies where they should be, put in the welding blankets to protect the hose cable assemblies and POUR METAL.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 04, 2020, 03:47:44 AM
Well so much for complacency - very minor snow fall last night, quite a bit of rain, and a major leak into the foundry  :bang:

The workshop side leak that I 'think' is water getting between the barge boards is no more than I'd expect BUT it looks like at least a gallon or so - probably more - has got in on the west side of the roller shutter, and run the entire length of the foundry underneath all the machines. The leak must be on the roller door end of the foundry and has run down the edge due to the tilt of the floor, but whether it has come under / round the door or through the roof is not clear.

I'm at my wits end trying to get this building sufficiently waterproof to actually use  :(

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 04, 2020, 05:09:06 AM
Looking at the internals of the roof over where the main ingress was I can find no damp patches so my preliminary conclusion is the water has come round or under the roller shutter, and when I have someone to assist outside with a hose I may be able to track it down.

However we obviously had much more rain last night than I thought as doing my rounds I find that our fields are flooded. Speaking to a friend who keeps a rain gauge apparently yesterday afternoon and night we had over two inches of rain.

. . . hey ho . . . mutter mutter mutter  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 04, 2020, 05:59:59 AM
So the rain stopped for ten minutes so I've applied squirty foam between the cement fibre and wooden barge boards on the main workshop. Note this is not intended as a seal in itself, but when trimmed back with a knife when set will allow the Cromapol roof gunge to bridge the gaps that otherwise are too big.

Bit of dribble clean up required down the cladding boards !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 04, 2020, 11:13:36 AM
Squirty foam expanded and set nicely despite the lowish temperature (4 deg C) so I managed to trim it back and slosh on the Cromapol fibre reinforced sealant, so fingers crossed it may have solved the leak on the main workshop side of the foundry.

Still trying to puzzle out the bigger leak on the west side  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on December 05, 2020, 06:56:41 AM
H Andrew,

Very crossed fingers! I won't be coming over for Christmas but maybe I'll get to see it later in the year!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 05, 2020, 07:24:53 AM
That's a shame Matthew but I fully understand.

Having managed to dry up the major flood (brushes, mops, then a powerful blower) I was able to carefully ply a hose on the threshold strip and totally proved that nothing was getting under it or round it. I then propped the hose up the channel that the shutter runs in and left it for a while so the water ran down the vertical channel as would rain hitting the shutter. Not a drop came in  :scratch:

Still need to test if rain is blowing over the threshold strip where the shutter D seal doesn't press as hard due to the sloping floor,  but that's a two man job. Might be able to persuade the other half to help this afternoon.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 19, 2020, 05:34:39 AM
So the good news is that I've not had water come in the Foundry now for several days. I've been busy slapping Cromapol on various joints, mainly the main vertical outside corner between the foundry and main workshop, which I'm sure has been a problem at times. Where the foundry abuts the original building where it is  'feather edge' wooden cladding, the gaps had been left as raw expanding foam which I have trimmed back with a knife and Cromapol coated. It doesn't look very pretty but it's certainly more water proof!

However it must be said that we haven't really had much rain - what we have had has mostly been over night - so I see wet paths in the morning but no real idea of quantities. Often what is forecast bears little relationship to what actually falls so I decided to rig up a 'rain gauge' . At it's crudest just a tin can, but then you have the pain of remembering to empty it out so I researched commercial devices and found a self emptying radio link jobby for only about £30 so not worth re-inventing the wheel!

It's a clever design that gathers the rain in a funnel and funnels it to a tipping rocker that when enough water is gathered tips over so the other bucket gets the water and transmits a signal to the receiver - all automatic, no emptying, and it accumulates data by hour, day, month and year.

Last night was the first 'active' night with rain - 2.5 mm - not a lot but still no leaks  :thumbup:

. . . time will tell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 19, 2020, 11:16:00 AM
Cool device Andrew.  :thumbup:

I feel funny wishing you this but I hope it rains hard where you are in the next few days, so you can feel confident enough to get the foundry going.

We, on the other hand just got an unwanted and insufficiently predicted  Noreaster day before yesterday that put down 60cm of snow with high winds. Negative 17 C out this morning. Miserable! To add to the problems my plow tractor had it's front wheels off waiting for new rims and tires a few days before the storm hit which were then delayed. Shoveled  third of a mile to the cars through this arctic mess to pick them up. Just getting them back on the tractor this morning.

Anyway, I wish you rain (only if you want it) !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 19, 2020, 12:08:14 PM
Oops Steve yes that sounds pretty bitter  :bugeye:

Odd isn't it, wishing for rain but yes that's the situation !

Now tell me about earth worms - tentatively moving one of the clothing lockers in the foundry that are waiting for that corner to be 'cured' of leaks I found a nice big juicy earth worm under it's base - locker at least 12 foot into the foundry from the outside world. Raising the roller shutter to throw it out, there was another equally juicy fat one under the shutter seal waiting for a chance to dash in (do worms dash?).

I have cameras pointing at the potential leak areas and first thing this morning doing my 'in bed by iPad' inspection there appeared to be a long thin trail of water from the base of the shutter inwards. When I got out to it an hour later I found it actually was ANOTHER worm trail but by this time it had dried out and there was a dead worm at the end of it :(

. . . what is it with these worms . . . what's so attractive about my foundry  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 19, 2020, 12:36:45 PM
Well I'm no expert but they respond to negative stimuli generally by going above ground. Vibration for one -- their mortal enemies, moles, make characteristic vibrations when digging, and the escape route is up and out of the ground for that. Subsoil life is kind of like undersea warfare with sonar signatures. Anyway, they can get fooled by equipment vibration. They also respond to stray electrical currents and will go above ground for that. Excess water will drive them above ground. And finally chemical irritation. So, any of that going on by your workshop: vibration, stray electrical currents, chemical compounds and solvents, or excess water?

Or moles?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 19, 2020, 12:46:09 PM
All of the above   :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 19, 2020, 05:14:58 PM


Richard Gene the Fishing Machine, one of my fishing heroes!  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 20, 2020, 05:19:24 AM
He's a bit over the top on the enthusiasm scale for a Brit  to appreciate  :bugeye:

So forecast was for very little rain over night, but actually it was pelting down at times and rattling the windows, so with a bit of trepidation I went out to inspect this morning. We had actually had 11.9 mm (or nearly half an inch) but yes there was a bit that had come in but dramatically less than on previous 'pre-sealing' days.

I rather suspect that some at least of what has entered has come under the bottom row of blocks of the wall - there is no DPC and anyway the interior slab extends beyond the wall outside at the same level. I need to flaunch a fillet where the wall meets the slab to cast the water away from the wall.

But look carefully and you'll see yet another worm visitor on this damp patch !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 21, 2020, 07:15:56 AM
Well definitely progress here  :ddb:

Another 24 hours with about half an inch of rain, but no under wall penetration in the corner where that last worm was. Why - well I put a generous fillet of sand and cement down yesterday where the wall meets the slab on the outside and it has worked  :thumbup:

The side wall of the foundry is also letting water underneath which is puddling behind and under the induction furnace driver box, and when I look outside it's no wonder. The ground falls towards the wall and there is a bally great accumulation on the outside where it's coming through.

I started yesterday digging by hand to fully expose the slab and dig a trench beside it so that I could hopefully get the water to flow away from the wall, and again add a generous fillet to the base. After about six foot of digging  that rapidly got unattractive. So this morning I managed to change buckets on the JCB803 ready for tomorrow when hopefully we have a brief dry spell.

But, looking on the bright side, water isn't now coming through the roof (I hope) and the problem is down at ground level.

Another major bonus is that the Water Board next door have now felled and removed the massive willow that was dumping leaves on the foundry roof. They promised to do this earlier in the year, and it had been over looked, so when they turned up to cut the grass last week I descended on them in my best persuasive manner resulting in the four man team with chain saws and a chipper reducing it to history over the next two days.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 21, 2020, 09:52:16 AM
Eight man days......I think that was a sequoia.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on December 21, 2020, 12:26:55 PM
Ah, so the edge of the slab was under the soil (and the transient water table by the looks of it). With no DPC, that seems to explain the remaining ingress. Certainly, keeping the slab clear by means of a drainage trench sounds like a plan. Beers all around!  :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 21, 2020, 12:57:49 PM
Eight man days......I think that was a sequoia.


No just Water Board employees !

Actually in fairness the main offending willow was surrounded by many smaller bits of scrub and smaller willows - all self seeded. Willow grows like a weed round here. Every year I get a neat little row of very short willow saplings growing in the gutters - easy to remove as they come out as a strip ready for planting - just pull one end and the rest follow !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 21, 2020, 01:00:52 PM
Ah, so the edge of the slab was under the soil (and the transient water table by the looks of it). With no DPC, that seems to explain the remaining ingress. Certainly, keeping the slab clear by means of a drainage trench sounds like a plan. Beers all around!  :beer:

Long term I'd like to put a perforated land drain in a trench by the slab covered in pea shingle - not sure of levels - I need to get the laser level out and see where I have sufficient fall to get it to clear.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 22, 2020, 03:43:27 AM
Major setback this morning.  :bang:

The entire foundry floor is covered in water - not puddles but like very heavy condensation. Now a bit has probably come under that side wall as it did the other day but I suspect that it's actually coming up through the concrete slab. I'll see if I can find any pictures of laying it, but I don't think that there is a membrane in it as it was originally intended as a yard.

I know that there is a rubble filled soakaway under it that I put in to take water from a surface water 'Acco' drain channel that was originally outside the sliding door to the welding shop, but has ended up in the foundry (so takes no water).



So what to do? I'll carry on and scrape the earth away from the side wall as I previously mentioned (but its too soggy today) but as for the floor the only two solutions that I can come up with are:

A/ Break up the slab and re-lay it with a membrane (difficult as the walls rest on it)
or
B/ Lay a thick screed onto the existing slab but on a membrane (not ideal as no bond between them and there will be screed thickness steps at doorways of 50-75 mm)

(or C/ Give up and take up stamp collecting !)

argh . . argh . . . argh . . . argh


Later Edit:

Searching my photograph archive the jury is still out.  Two relevant  pictures, one showing the Acco drain pre-concrete and another that has some unlaid membrane in the vicinity but not laid so I'll have to excavate the side of the slab to be sure either way




Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on December 22, 2020, 05:37:50 AM
Andrew,

What a pain!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 22, 2020, 07:14:09 AM
Yes Matthew I'm utterly fed up with the whole business  :(

Very difficult to take decent pictures of the issue but these give you an idea of the extent of the wetness.

This equipment should have been in use MONTHS ago - everything works but I daren't use it in full flow pouring metal when things are as damp as they are.

I do occasionally run up the generator and switch on the induction furnace driver and get something glowing to try and keep the internals from getting too damp but that's a different ball game from pouring metal.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on December 22, 2020, 07:31:47 AM
I'm afraid that I would be forced to just 'put up with' that given that the damp is in the slab not on it. The benefits don't out-weigh the effort involved IMO. The weather is seldom as wet as it is right now, it might just be that the ground is so sodden that no soakaway is going to work. That's bound to bring the damp up through.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on December 22, 2020, 12:46:00 PM
Well, a land drain trench around the slab might at least lower the water table under the slab. That way at least you wouldn't have water wicking up from below when it rains.

I have reinforcement and DPC under my slab but I have a different issue. The cowboys who laid it either levelled it off too much or did it when it was pissing down. Consequently there was standing water on the surface when it was trying to set, so the surface has no strength and has a cratered surface. Really not what I was planning and made the surface paint laughably pointless. I was in China at the time otherwise I might have twigged WTF they were up to.

Murray
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on December 22, 2020, 03:28:05 PM
It could be condensation dripping off the underside of the sheets and then soaking in to the floor, maybe best to go in there when the temperature drops at 3 or 4 in the afternoon, and check for moisture on the underside of the sheets. You would have to cut the concrete at the edge of the walls to put a membrane in, but what a pain! Could you dig (though it is hardly the weather for it) an exploratory tunnel under the concrete to see if there is a membrane. I think that it is very unlikly that the water has come up through the concrete overnight, when it was previously dry, but I do not know your local conditions as to water table height, and also how well the concrete was tamped. Still, I think if it was coming up through the concrete, your yard would be virtually under water! Have a good Christmas, it will soon be time to put all this behind you, fill your glass, and put your feet up! All the best Andrew, hope you get it sorted, as I may have a little commision for you!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 22, 2020, 11:51:31 PM
Portland cement neat is waterproof. I have a 3000 gallon above ground cistern that does not leak weep, or get damp. the inside and outside are painted with a heavy coat of pure Portland mixed with a small amount of sharp sand to increase coating thickness and give tooth to any needed subsequent coats.

If it was me, I'd paint the floor with a heavy coat of pure Portland and a little sand, then while wet, put down reinforcing steel mesh and add another 4" of very rich concrete over. I'd skip membranes, as yes, you'll get no bond at all , and it's just wasted plastic  technology BS. You'll just have a layer of water between. Raising the floor 4" will help with drainage, too.

4" minimum over and yes, reinforcing, so nothing moves or cracks ever again. When semi cured, I'd hit the top surface with one more coat of Portland and sand. This whole will be waterproof.

Drainage won't stop a permeable pad with water under. You want impermeable, and made out of like materials. Forget plastic miracles. Sure, improve drainage, but a spongy concrete slab is just that, a sponge.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 23, 2020, 04:19:10 AM
Thanks for the comments chaps.

I don't think that it's condensation from the roof - if you look at the picture above that shows the Acco drain in the concrete floor as is at the moment, there is no damp on the welding shop floor and the welding shop side has the exact same roof construction and the sliding door between has been open for weeks so the same climatic conditions.

This re-inforces my suspicion that the foundry slab has no membrane.

When and if this spell of rain stops I'm going to :

A/ Clear the earth as far back from the slab as possible - 2 or 3 foot probably

B/ Trench down beside the slab about 12 inches

C/ At the mid point of the wall dig a sump

D/ Temporarily install a mucky water sump pump and try and depress the local water table

If this works I'll go the whole hog and turn the trench into a french drain with a perforated pipe and shingle and properly install the pump though where to pump to is an issue at the moment. (Need to check levels but it's still raining hard so that's not happening just yet!)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Gadabout on December 23, 2020, 03:07:24 PM
Andrew,
So why hasn't this dampness showed its ugly head before?
dedicated awemawson follower
Mark
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 23, 2020, 03:42:32 PM
As Pete said it has been pretty wet recently, but probably it has been pretty dire before, but the room has been packed shoulder to shoulder with bits being stored. So actually not a place I could get into regularly.

Don't forget that the original chiller unit had succumbed to storage, quite possibly due to the damp, and the Induction Furnace Driver metalwork was badly affected especially on the first foot of height. 

The building was really badly conceived (by me) - that slab was cut into rising ground with no drainage provision, no membrane in the floor, and I let the contractor get away with far too shallow a roof pitch.

. . . but we are where we are and I have to make the most of it !!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 26, 2020, 10:15:24 AM
Boxing Day presented a 'weather window'. It only rained 4 mm on Christmas Eve, none at all on Christmas Day, and Boxing Day morning was predicted to be fine with a bit of rain in the afternoon, so time to start to solve the ground water problem with the foundry.

I decided to form a shallow ditch, or 'grip' as they are called in these parts, to allow water to flow away and past the building to lower down in the field, so I got the digger into position ready to start after breakfast.

Now traditionally early Boxing Day morning my friend Phil cuts the hedge for me on the main road outside the farm. He chooses this time as it pretty well guarantees a low traffic flow on the A21  which is a trunk road.

Phil is a very experienced ground worker and has dug footing and laid masses of concrete for me over the years, so it wasn't long before he evicted me from the cab and started making a very professional and far neater job than I could have hoped to achieve (well, OK, I'd hoped that this would happen  :clap:)

The plan is to form the grip and see how it performs - if it solves the issue very good, but if not there will be a 'phase two' where the grip gets 100mm perforated pipe covered in 20 mm pebbles as a french drain, and the pipe is trenched onwards into the farm yard and coupled to the existing field drain system (that takes the bore hole overflow incidentally)

What to do with all the spoil? Well there was a redundant 'goose pond' (the geese now being history) that needed removing - so the liner was broken up and the pond and surroundings filled with the spoil - there was quite a bit!

Heavy rain forecast for tomorrow so hopefully the grip will be tested ! The foundry floor is nice and dry, lets see what happens  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 07:12:49 AM
It looks like that 'grip' was dug just in time - we had rather a lot of rain last night and it was blowing a hooley  :bugeye:

My new rain gauge said 9.9 mm but I knew that we'd had far more than that - sure enough the sensor bucket had been blown away ! I must make a heavy base to screw it to.

Chaos this morning as we had two power cuts over night - first one about midnight was about an hour, but then one at 5 AM lasted until 10.30. Doing my rounds I find all fields flooded, and flooded more than I've ever seen it in the 13 years we've been here. It's the first time that I've seen a raging torrent - (The River Brede) entering the orchard having already crossed the road and is probably the main contributor to the flood.

A knock on 'collateral damage' issue is that our Klargester private sewage system is flooded - it pumps treated effluent into a local stream, but I think the stream is now at the same level as the body of the treatment unit and of course the power has been off for a long time so the pump hasn't been working. Hopefully the waters will recede over the day and once the level goes down the pump will stand a chance of restoring order.

Quite a bit of water entered the foundry - the vast majority via the roller shutter, the side where the grip is has suffered very little so it looks as though that's working. I'm really not at all surprised as it was an 'interesting' night from the weather perspective. One roof sheet 'overlap' has let some through but that's down to the very strong winds that we've had.

The rain was lashing down - I think we were predicted 50 mph gusts and from what was happening to my bedroom window I reckon we had them.

But it's not all gloom and despondency - all the sheep have got to higher ground so no wading about rescuing them.

But I'll have to invoke 'phase two' of that grip to let it empty via the field drains.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on December 27, 2020, 07:55:18 AM
Wow. I guess that is The Goose's Revenge. That'll teach you to eat them and fill in their pond!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 08:01:10 AM
And we didn't even eat the geese - they went to a friend.

26 mm fell last night according to a friends rain gauge - I'm hoping for at least one dry day for this lot to run off - it usually clears pretty quickly.

Today's job - heavy base for the rain gauge !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 09:34:22 AM
Well the day is improving :thumbup:

Water levels haven't noticeably decreased BUT the Klargester has come out of the alarm state and the pump has managed to reduce the level in it's internal chambers back to working levels despite this being below the stream level still! So I can let the wife use the loo and washing machine now  :clap:

A quick and ready weight was needed to stop the rain gauge collector blowing away again - the scrap box yielded a nice bit of three by one inch steel that in a former life had been the articulation link on my Thwaites 2 ton dumper - rescued when I replaced it's bearings. A quick slice on the cold saw, a tickling with a 36 grit sanding disk, four holes drilled and tapped M 4, followed by some zinc rich paint and hopefully it's now heavy enough to take a bit of wind!

AND the weather forecast is no rain for a couple of days - good, I reckon we've already had January's rain fall last night!

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on December 27, 2020, 11:34:22 AM
Man that's flooded. The ground must already have been very waterlogged.

You didn't have to go and rescue any livestock this time Andrew?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 12:26:46 PM
Fortunately not Pete, all the sheep managed to get to higher ground all be it  waterlogged islands ! As you know soaked sheep are unbelievably heavy to move !

I gave the go ahead today for phase two of the grip - installing perforated pipe and taking it to the field drain system that leads to the stream. About four foot or so of head from the far end of the run down to the existing field drain so should flow OK
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 27, 2020, 02:02:09 PM
Andrew, but that can't be happening every time you get an inch of rain? It must be from already saturated or frozen soil. An inch of rain is a lot in 8 hours, but surely not a once in 13 year full flood event under normal circumstances?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 02:45:45 PM
We are at the bottom of a shallow valley (the River Brede) where it comes close to us the banks haven’t been cleared for years. The Environment Agency have the responsibility but recently have put in all sorts of stupid rules. Only one bank can be done each year to keeps the green lobby happy. The workers aren’t allowed to use diggers closer than a certain (fairly long) distance from the banks to keep the safety lobby happy. Result: there is about a mile of choked river that can’t take the flow. Quick growing willow roots block it. Today the A21, one of only two trunk roads in East Sussex, was closed due to the water pouring into our fields Its just office based official nonsense.

And to add to the problem yesterday we had had several days of heavy rain saturating the Brede catchment basin.

Oh and it happens most years to a greater or lesser extent. It’s actually the second time this year! Last time was only 4th December so three weeks ago. It all drains away very quickly, tomorrow there will be very little sign left.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 27, 2020, 03:01:45 PM
That's a difficult situation. I guess the problem is that what would normally drain your land becomes the source of the water on the land. So there's no solution until the river drops.

Here, as a result of much study after the Irene hurricane flooding they are also recommending not to clear riverbanks where possible and let deadfalls lay, but not for environmentalist concerns, but because the worst flooding damage occurred as a result of stream flow rates having increased so much because of channel straightening and bank clearing. The high speed flash floods wiped out major roadways throughout the state, cutting them up with steep ravines, and displacing millions of tons of substrate.

I guess there's no ideal way to reduce flood damage. What helps one situation hurts another, depending on the severity of the downpour. Of course a hurricane of tbat magnitude up here is a once in a century occurrence.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 27, 2020, 03:27:59 PM
Well Steve these things go in cycles. When the Romans were here (AD43 onwards) the end of our field was a Harbour exporting iron !

Even in Victorian times the Brede was navigable up to Sedlescombe Bridge about 100 yards from the end of our field, but now you might just get your canoe up it.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on December 27, 2020, 05:46:31 PM
Near us, Preston used to be a major sea port, about 10 miles inland. Now the Ribble is` pretty much a muddy ditch and you'd lucky to get anything bigger than a canoe up there. Most of the docks have long gone, leaving one basin that is laughably called the "marina", with about 20 boats. There can only be a few days a year when it's possible to make the journey, assuming you have a day to waste, so I can't imagine why anyone would keep a leisure boat there.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 28, 2020, 04:41:18 AM
So 24 hours later and a few millions of gallons of run off later there is little sign of yesterdays flooding!

(Actually this is typical)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 09, 2021, 02:25:46 PM
Phil rang me last night to  announce that he was dropping off his 3 ton digger, and starting this morning would be finishing off the land drain connection. I warned him that I'm emulating a peg leg and couldn't be any help at the moment as my trapped nerve is still playing up - but 8 am there he was with all his Tonka Toys - Phil likes his ground work machines - he has diggers ranging from 3 to 36 tons and all pretty modern - no, I'm NOT jealous (much!)

To get the levels he started by exposing the existing land drain in the driveway (the one I connected the bore hole over flow into) and then started deepening the grip along the side and end of the foundry. This exposed two cast iron pipes. A smaller 3" one that I was aware of that had taken water from the old settling tank (that is now under the Tractor Shed) and was definitely abandoned, and another much larger 6" one that doesn't feature on the plans or way leaves but almost certainly is the main feed from the pumping station to Sedlescombe Village. If you look, it is UNDER the corner of the slab that the foundry has been built on. They have no way leave for it so not my fault !!!!

Finding these pipes determined the depth of the  grip / french drain, so that the new perforated pipe could pass under them and yet still have the right fall from end to end.

Once in place the perforated land drain was covered in pea shingle and a line marker laid from it's end to the connection point.

Trench then dug carefully avoiding water and electricity pipe to the greenhouses, a feed to an outside tap, and the flow and return for the furnace chiller. No pipes were hurt in this exercise - thankfully.

Then it was a case of connecting into the existing land drain, back filling and tidying up. everything is very wet so the end finish is rather 'slick' but time and rain will cure that as the grass grows back - I hope!


. . . .cont
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 09, 2021, 02:28:24 PM
.... cont
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on January 09, 2021, 03:51:31 PM



-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on January 09, 2021, 05:57:19 PM
Good to see some proper toys on the job.  :thumbup: You did not mention all that clay being a problem, gluing itself inside the bucket, which is what happens to me if any attempt is made at earthworks in our current kind of weather.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 10, 2021, 02:57:23 AM
It is amazingly sticky stuff. As soon as you get it on your boots you start accumulating stuff and the going gets heavy. By the time you walk over the pea shingle you’re REALLY weighted down !

It all hoses off though thank goodness
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 10, 2021, 09:06:00 AM
Andrew, I expect to see some molten metal from that vicinity soon!  :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 10, 2021, 10:19:55 AM
One can but hope Steve !

In all fairness it already has done a brass melt since it’s resurrection but only small quantities. My welding shop floor has a load of 100 x 6 mm strips 6 meters long waiting to be made into flasks when I get my “get up and go” back, but movement is a bit painful at the moment.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 11, 2021, 04:39:32 AM
Andrew,

Just a thought, I have quite a large collection of wooden flasks, I don't do any "series production" casting, which means that I make flasks almost every other casting as needs differ.

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 11, 2021, 06:17:18 AM
Matthew yes basically that's what I used to do for odd shapes but I like to have a stock of 'standardised' boxes that will mutually connect vertically and are ready 'on the shelf' for quick jobs. I had loads but it seems I gave them away!

For my wooden boxes I used to use sash window locking catches. Boxes were hinged at one corner with the catches at the other, so with sodium silicate set sand I could release a block of set sand onto the moulding floor and hence need less copes and drags.

Here are some 1" diameter piston moulds and cores that I did that way some years ago
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 11, 2021, 01:46:12 PM
Snap flasks. Cool. Do you have any photos of the pistons, Andrew?  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 12, 2021, 07:05:08 AM
Andrew,

I can see snap flasks as being really useful with lost PLA in silica sand Sodium Silicate molds! Burning out the PLA would be better without the flask! I use petrobond so it's not the same problem for me yet, I have just bought a really cheep 3D printer, which because it's cheep, is proving to be somewhat challenging to get together! I have a foundry supplier near me so I was thinking of going the other route, investment plaster for lost PLA, My kiln, which is vertical, "200liter oil drum gas fired) top opening will allow me to pour molds hot without removing them.

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 12, 2021, 10:55:14 AM
I'm wondering if those piston molds are baked or solidified somehow (sodium silicate?) because it looks like they are meant to be stood up from their present positions. Without a flask, that would seem difficult. Well, maybe the flasks were replaced for the turnng operation?

I'm guessing the cone ended hollows are giant sprues. Or if they aren't meant to be poured that way, and lie on their sides, what prevents the horizontal cores from popping out during the pour if there is no flask to hold them in place?

What's the scale of this -- maybe it's smaller than I imagine. I was thinking full size engine pistons, but if this is model scale, it would be easier to understand and the sprues might actually be small.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 12, 2021, 11:12:52 AM
Steve,

A/ They were for 1 inch finished diameter pistons

B/ The sand was silver sand and 4 % sodium silicate

C/ They were stacked vertically, several at a time, and clamped with a sash clamp

D/ The alloy was one of the LM series from a scrapped large Diesel engine piston

E/ Initial ingotting was a pain due to steel reinforcement in the original pistons

They turned out rather well. The white colour is parting powder. It must be 15 years since I did them!


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 12, 2021, 11:48:39 AM
Thanks, Andrew!
Title: Re: CFEI 100 KVA Induction Furnace - Molten-Metal
Post by: awemawson on January 21, 2021, 09:32:38 AM
Every now and again I start up the generator to warm it up and blow the spiders away, and often fire up the furnace for the same reason - but it gets boring just heating a bit of steel to a nice cherry red, and I'm still not equipped to actually decant any into moulding boxes (no boxes made yet and the pump up table that will hold my moulding boxes during a pour currently has a VAST transformer on it that I can't move single handed  :bang:)

Now kicking about at the back of my bench has been the remains of the die cast frame of a Dell Optiplex 'All in One' frame (PC and monitor all held together for desktop convenience - I just wanted the PC sleeve and it's mounting to screw to a wall by my desk!)

So rather than chuck the scrap out it got popped into the crucible during one of those 'spider clearing' sessions this morning. I reasoned that it is either a zinc or aluminium alloy, and if left to cool in the crucible it should shrink enough to shake out - just so long as there is no antimony in it, as that EXPANDS on cooling !

Sure enough hitting it with 30 KW for three minutes produced  one kg of molten mystery alloy and on cooling it was easily removed - so what is the alloy?

This question prompted me to dig out my "Analoy Portable Alloy Identifier" - I'm sure I've shown it here before but probably a few recently joined members won't have seen it. There has an 8085 (I think) embedded microprocessor driving it. Basically you strike an arc between a graphite point and an earth terminal and the device gathers up the emitted spectrum and works out what proportions of what metals  are present. (A predecessor to the XRF analysers of today)

Not surprisingly it turns out to be  85% aluminium, 7.5%  silicon , 1.27% copper,  1% zinc with traces of Magnesium and manganese but what did surprise me was the 3.64% of Iron. I'm not at all sure that that was a deliberate inclusion or maybe something dissolved into the mix during processing.

 . . oh and yes I HAVE ordered a new ribbon for the printer !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on January 21, 2021, 01:37:39 PM
Sounds like chinese aluminium! not enough copper for duralumin, nowhere near enough zinc for zamak/mazak type alloy, so it must be  mongrel aluminium! I like the look of that Analoy box of tricks. Clever stuff! How is the water level?
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 21, 2021, 03:15:50 PM
I've no doubt that the die-casting WAS made in China - much Dell stuff is / was but it actually was a very well made item.

No doubt the Chinese Dell assembler would have subbed out the die casting and although the alloy would have been specified the correct specification material probably wasn't used.

Subbies not using the correct specification materials has happened before. The MOD had a new sniper rifle, developed by Accuracy International who were a small outfit. When many more than they could provide were ordered the manufacture was subbed out and the wrong steel was used for the firing pin resulting in dangerous jamming and breaking - the weapon firing when the bolt was closed and not waiting for the trigger to be pulled  :bugeye:
 Accuracy International brought manufacture back in house and re-designed the  pin so that it was visible at the rear of the bolt but of course if the right steel had been used it wouldn't have happened anyway .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 21, 2021, 03:59:43 PM
Sounds like chinese aluminium! not enough copper for duralumin, nowhere near enough zinc for zamak/mazak type alloy, so it must be  mongrel aluminium! I like the look of that Analoy box of tricks. Clever stuff! How is the water level?
Phil

No more major floods but still loads of condensation on  the floor the minute we go from cold to marginally warmer
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 21, 2021, 06:33:19 PM
I'm sure you know Andrew, the only practical remedy for that is to seal all outside air openings as much as possible. Unless we heat the space, or dehumidify, or insulate above the slab. Well, or wait for spring.

I feel your pain. I think it's a common experience for any of us with small shed shops, unfortunately whatever the slab is doing in a high humidity warming environment, anything massive will also do, even if the slab were covered. So equipment in that situation will also have condensation on its surfaces. Even metal stock.

If a shop is tight and insulated -- that is lessened because the shop goes through longer temperature and humidity transitions than the outdoors so it sort of averages out enough to make the temperature differentials of massive objects and the air non-condensing.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2021, 11:53:21 AM
Yes Steve, little chance of sealing it up and keeping it warm - the building was built to be drafty  - I'd intended to put a gas powered furnace in as well as the induction furnace so needed to loose heat !

I'm controlling the problem at the moment using a powerful squirrel cage fan blowing across the floor at low level, and as the weather gets better hopefully the slab will dry out a bit and lessen the issue now the external drainage has been installed. This fan is intended for drying out premises after floods - so highly appropriate !

My intention was to somehow shift the big transformer and get on sorting out the foundry infrastructure but I got distracted by having to sort out my Hydrovane 502 compressor - I knew it was due a service and was getting slower to build up pressure, but when I drained the oil from it and opened it up I found that the 'separator cover' was cracked around the housing for the minimum pressure valve. I managed to source a replacement which along with new O rings and oil has solved the problem, so back to the foundry !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2021, 12:05:34 PM
As I'm a bit more mobile now I thought I'd try and tackle that transformer, get it onto a small dolly that I used to use for oil drums, and release the pump up trolley for the foundry.

How hard can it be, after all gravity was helping as the dolly was much lower than the lowest setting of the pump up. Well, actually NOT that easy but no fingers or toes were lost and it's now on the dolly - phew. IF ANYONE WANTS a 240 volt transformer for goodness sake come and take it away. (I'd intended to make a very large 3 phase converter with it but now I have proper 3 phase)

So - to clear a bit of space I decided to initially concentrate on the 'tilting' furnace body and put the 'inverting' one in storage for the moment - it got tucked away in the generator room once I'd worked out how to roll it's not inconsiderable weight over the threshold strip that I'd installed to keep rain out (answer - sheet metal ramp and take a run at it  :bugeye:)

This allowed me to move the tilting body to close to it's final resting place, and offer up the pump up trolley. My intention is to make a stand to take a ring shank pouring tool for most pours, but the trolley will be used for simpler stuff direct to the mould.

. . . but that's in the future - at least a bit of progress after several weeks of enforced inactivity.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on January 22, 2021, 02:49:34 PM
I can't believe you haven't got a hoist somewhere that you could use to lift your transformer.

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2021, 03:29:27 PM
Got got a blooming great fork lift but I couldn’t get it near enough due to clutter.  :bang:

I’ve got an old (actually new never used but old if you know what I mean) Haltrack engine hoist that was so tangled I gave up !

In the end I just did a highly risky tip and hope job !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 23, 2021, 09:59:30 AM
Today's Job - Find my ingot moulds ! I used to have two ways of producing ingots from scrap.

Firstly I had (have) several ingot shaped blocks formed from wood as patterns, and painted to lay on a board to make open moulds using sodium silicate sand. I've cast hundreds of ingots using these patterns and I've actually managed to locate them - but I'm not yet ready to mill sodium silicate sand (although I have all the materials)

Secondly I had a series of ingot moulds formed from inverted angle iron with plates welded on the ends - sadly these are long gone and lost in the mists of time.

So today, armed with a length of 3" angle iron left over from the Generator Room build, and a plate of 3 mm steel that originally was part of the CNC Plasma Table before I re-built it, I set to to make one at least so that there is somewhere to pour the left overs of melts.

Simple welding job, but of course you have to test it don't you  :clap:

First attempts didn't go too well - I was anxious not to 'stew' the melt (that bit of die casting that I melted yesterday) and when I came to tilt the pot to pour the metal out it solidified as I did it  :bang:

The good thing about foundry work is that you can hide your mistakes by melting them down again  - second time no worries about stewing - just wack some 45 Kw into it until it's jumping out of the pot, turn off the induction driver and pour it. No issues with flow this time but it did show the the floor istn't level !

Now I need to source some aluminium alloy scrap - I had  huge pile of ingots before I moved here - they all went to the scrap yard to avoid having to store them - so now I'm looking for clean engine / gearbox /  castings to replenish my stocks.

It's mighty fine just being able to start the generator and bore hole cooling system, kick off the Induction Furnace and produce molten metal on demand with very little fuss and bother and pretty quickly.

On the Generator I did notice a minor diesel leak on a fitting on the feed from the tank to the lift pump - just a drip but I need to sort it - don't want to return from a melt to find the generator on fire   :bugeye: Of course the tank shut off valve is stuck firmly open so I'll let everything cool down and probably tackle it tomorrow. It's the type with a taper core, so it probably just needs a tap in the right direction to free it but not while the engine is hot I think!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on January 23, 2021, 01:21:54 PM
Excellent progress Andrew, now if you had an old tractor radiator with an electric fan behind it, you could shove the cooling water through it and keep the foundry dry in winter!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 04:57:12 AM
First thing this morning I gingerly applied a bit more force to the  generator diesel tank shut off valve and managed to close it without snapping off the delicate operating lever - phew ! It's ever so stiff but it's probably not been used in twenty years.

This means that I can dismantle the down stream plumbing towards the lift pump and re-assemble hopefully to cure the weep. Careful examination tells me that it is entirely possible that the leak is actually at the cover gasket of the lift pump. I presume that there is a mesh filter under it. Anyway I'll dismantle the cover and the gland fittings and put it back together with some loctite thread sealant.

The lift pump is by AC so I need to google drawings if any exist for this 1970's item.

But not just now - it's only minus 1.5 deg C out there but feels a lot colder. Being a wimp I'll do it when it warm up a bit !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on January 24, 2021, 05:07:37 AM
it's just dropped below 30 here... Degrees c that is - at 9pm.
Expecting a low of 25 at 2am then 40 tomorrow.
(Melbourne, Oz)



-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 05:30:13 AM
I'm on my way Russ, put the beers in the 'fridge !

Well it turns out that my policy of getting my hands on all documentation that I can regarding newly acquired second hand machinery has paid off  :ddb:

One of my eBay purchases was a full manual for the engine - well for one very similar actually, and in it are three pages dedicated to the lift pump along with an exploded diagram. Rather over the top I reckon as the construction is entirely conventional - these lift pumps are all very similar. My Italian cold saw uses one for cutting oil off some Italian vehicle  and when it failed I was able to replace it with a spare that I had held for my JCB digger! In fact even the internals were interchangeable.

So as suspected there is a filter under the cover which I'll whip off when the wind changes.

(Photos attached at higher resolution as they are a bit detailed)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 10:01:49 AM
This afternoon I pulled it all apart an hopefully have sorted the weep - time only will tell.

When I looked closely at the picture of the lift pump I realised that there were distinct signs of fatigue crystallisation of the solder joint retaining the ferrule onto the diesel pipe, now this is lower than where I saw apparent weeping but with an engine vibrating odd things happen with liquids.

To satisfactorily re-solder the ferrule involved removing the rather long and complicated fuel pipe - easy enough except that there are three spring clips retaining it that are fixed with self tapping screws into the engine casting. Every similar clip screw holding the wiring when I re-built it sheared off, so this time I carefully bent the clips to release the pipe. After that just two ferrules to unscrew. Blow the diesel out of the pipe, clean pipe and ferrule and re-soft-solder. I think fittings like this should be hard soldered, but it's lasted best part of 50 years so far and it's pretty well impossible to clean solder off sufficiently to let you hard solder / braze.

Then I opened up the lift pump and cleaned it up, unscrewed the inlet coupler, re-fitted it with Loctite Thread sealant, cleaned up the cover and it's rubber seal and re-fitted it with a smear of sealant.

Once the pipe was re-fitted (clips a bit of a pain!) I turned back on the tank stop cock, slackened off the lift pump inlet fitting bleeding diesel through, tightened it up again and crossed my fingers starting the eingine.

No dramas, engine fired up normally and I ran it for maybe five minutes to no apparent weeping. However I've just been out to check it and darn me if there isn't weeping from the lift pump cover gasket  :bang:

Not a major issue if I can find a replacement - it's domed - not sure if that is by design or by age - may be a flat one would work inwhich case I can make one  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 11:26:02 AM
As I have  no model number for this pump, just Dorman’s part number, finding spares is not easy. I’ve measured the body of the pump it's about 58 mm but 'rebuild kits' on the web show a smaller diameter body.

I laser cut a pair of 0.4 mm fuel and oil resisting paper gaskets, but wasn't convinced that they'd have sufficient give. Also rather oddly the central pillar on the pump into which the cover retaining screw fixes protrudes a few thou higher than the out sealing rim - maybe the cover has been over tightened? Anyway I rejected the 0.4 mm paper in favour of some 2 mm nitrile bonded cork gasket that I had that claims to be fuel and oil resistant. Now I know from previous attempts this stuff doesn't cut on the laser - it just burns - so it was a scalpel job. But after all it's a dead simple shape.

Anyway I've fitted it, bled down the diesel again and run the engine for a few minutes, and so far no weeps - but I've been here before so I'll withhold judgement for a day or two!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 24, 2021, 04:31:32 PM
I've had poor luck with my own made rubber/cork gaskets they seem to deteriorate fairly quickly. I don't know why. May be the quality of the material I've bought locally.

Andrew are you sure that's not meant to be more than just a gasket, ie a flexible diaphragm?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 05:12:05 PM
Steve I’d had the same thought before I pulled it apart,  but the working diaphragm is in the next layer down and sound as far as I can tell. On the far side of that diaphragm are in inlet and outlet valves, this upper chamber being an inlet reserve.

If you look at the exploded diaphragm above it’s all explained I think. Part #10 is the working diaphragm. 

I went out just now to check, and it’s dry as a bone I’m glad to say. It’s pretty good quality gasket material with cork bonded together with nitrile. You can’t pull it apart by hand. It’s the same material that I used on the housing for the water jacket thermostats and that’s holding OK.

I’ll run the engine for a more prolonged period tomorrow. I’ve a feeling that I have a large Lorry piston tucked away that can be turned into ingots !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 24, 2021, 05:19:57 PM
I'm thinking though not the pump diaphragm, it might be a damper diaphragm.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: RussellT on January 24, 2021, 05:26:27 PM
I assume we're talking about part number 4 on the exploded diagram.

If it's just a seal why would the cover need to be that funny shape with an air space under it.  Could this be a diaphragm to maintain pressure while the working diaphragm is being pulled back?

Russell
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 24, 2021, 05:34:54 PM
When the working diaphragm is pulled back fuel is forced through the outlet valve to the injector pump.As it returns the inlet valve opens and fuel is admitted to that space from the tank .. I don’t think anything maintains pressure other than by part 10 moving.

It started fine and ran for a few minutes quite happily but we’ll have to see how it works under load tomorrow !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 24, 2021, 06:30:55 PM
My guess, only a guess, is that the air space and the diaphragm damps the pressure pulses from the main diaphragm. And perhaps cushion the main pumping diaphragm as well from extremes of motion. In any case if missing, I wouldn't expect it to show up as an immediate problem. And if the cork and rubber gasket serve as a new damping diaphragm (if I'm correct at all), then function is fully restored, as long as it lasts.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 24, 2021, 06:45:36 PM
It's called a pulsator diaphragm. Though I can't find something exactly like yours, here are two similar images that label it:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 24, 2021, 06:57:42 PM
And from the mists of time -- 1945 to be exact, a pretty interesting document find:

http://www.easy39th.com/files/TM_9-1828A_Fuel_Pumps_1945.pdf
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 25, 2021, 04:11:48 AM
Wow Steve that's quite a document - and yes I've been through it fully ! Who'd imagine there would have been so many minor variants. Many have the pulsator diaphragm, several don't and some have an 'air dome' presumably for the same function.

What I find odd about the rubbery one that I removed is that the illustration definitely shows it as flat, whereas mine is exactly curved to sit fully against the cover with no air (or fuel) behind it, and it is fixed at the periphery by the cover and the centre by the retaining screw thus greatly reducing any potential movement.

No  weeping over night and I've found the massive pistons that I thought I had so I'll do a melt today and load up the engine  and see what happens. But first I need to work out how to cut up the pistons - at 5.25" they won't quite go in the crucible  :bang:

Weighing in at 3 Kg's each it must have been a big engine that they came from !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 25, 2021, 05:15:57 AM
The other day I managed to break my coarse bandsaw blade for my upright Startrite 18V10 bandsaw, and although  it has a blade welder, this particular blade stock  doesn't butt weld very well, so . . .

. . . it had to be the horizontal band saw which gives worse holding issues with a piston shaped object - however two cuts and one piston was reduced to manageable pieces for the pot.

I deliberately hit it with rather more energy than really needed as I wanted to load up the engine to make sure that the lift pump was pumping at a goodly rate. 50 kW and the alloy was jumping out of the pot, but the engine note never missed a beat.

So one piston reduced to ingot and the lift pump is performing apparently OK, however I strongly suspect that with the tank sited where it is at least 12" above the injector pump it would probably run without a lift pump at all!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 25, 2021, 05:36:30 AM
Hi Andrew,

I imagine that here are no gas bubble problems with your induction furnace! I was thinking, is it worth ingotting? By the way , you probably know, Al car wheels are a really useful alloy, tyre shops are sometimes a good source!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 25, 2021, 07:24:36 AM
Not sure about gas bubbles yet Matthew as I've not machined any of it, but it's on the to do list - in fact I'll try and do it this afternoon.

Yes alloy wheels generally machine nicely when cast, but with tight lock down at the moment I cannot drive around  to make suitable contacts. It's tempting just to buy an expensive pallet load of LM4 or LM5 - no point in small quantities as the transport gets too pricey.

(Awaiting my invite for the vaccination as I'm in the second tier age-wise - hopefully this week)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 25, 2021, 08:38:49 AM
OK Matthew, I've machined both the 'Diecasting Alloy Ingot' and the 'Piston Alloy Ingot'

No signs of porosity / gas bubbles in either and they machined beautifully, despite being a rough and ready hand feeding bit of machining using an end mill out of my 'waiting to be sharpened' box !

Quite pleasing really  :thumbup:

(no saying if there are defects further in, but this is a good indication )
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 25, 2021, 10:21:19 AM
What I find odd about the rubbery one that I removed is that the illustration definitely shows it as flat, whereas mine is exactly curved to sit fully against the cover with no air (or fuel) behind it, and it it fixed at the periphery by the cover and the centre by the retaining screw thus greatly reducing any potential movement.

HI Andrew. My experience recently rebuilding a couple of outboard motor fuel pumps is that plain rubber diaphragms do often retain stretch over time even though they may start out flat. I also think that some of the modern fuel additives (not just ethanol in petrol but also additives in diesel) can soften the rubber and accelerate that kind of aging.

In normal usage, even though the pulsator is pinned down in center, the thinness of the rubber does allow elastic flexing into the space surrounding.

I think you're right that the height of the fuel tank relative to the engine intake probably provides fuel pressure by itself. I think the function of the pulsator diaphragm is not to provide fuel pressure (that's the function of the pump diaphragm) but to smooth the fuel pulses, and reduce the peak loads on the pump diaphragm and fuel line components. I don't think problems if any will show up in the short term.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 25, 2021, 11:43:37 AM
Amazing what a new ribbon does for a till roll printer !

This is the analysis of the 'Piston Alloy'
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 25, 2021, 01:58:54 PM
Hi Andrew,
I thought that bubbles would be unlikely as your atmosphere doesn't have anything like the hydrogen content that a gas fired foundry has. I've made a de-gasser, (based on "olfoundry man's" one using Argon)  that I've started a video on, I just need for the weather to get better so that I can get outside and do some more casting!

Nice to see the results of the Pistonium analysis.

Good news about the vaccination, my ex-mother in-law who is 96 can't get one in Seaford.

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 26, 2021, 04:42:14 AM
Matthew I used to de-gas aluminium alloys with a simple Argon probe. A length of 15 mm stainless steel  plumbing pipe, flattened to seal it at the 'hot' end, with a few 1 mm holes drilled in. Probe connected via flexible pipe to Argon regulator which I set to just bubble up through the melt.

In fact this is why for many years I used straight Argon for mig welding - I was too tight to rent two cylinders! I now have returned the Argon cylinder and have Argoshield which is much nicer for welding but I doubt that it would de-gas aluminium !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 26, 2021, 07:04:19 AM
Andrew,

I only have Argon, as I've don't use my Mig, most of my life I only had a stick welder! The Mig is up for sale, it a very good 400amp welder, withe a sattelite on 10meters of cable!

Olfoundry man's de-gasser does exactly that, it has two disks (mine are cast iron) bolted together with radial lines scratched into one of them, , the argon is fed from the centre between the two discs the scratches are a few 1/100 of a mm which gives very fine bubbles which apparently pick up the hydrogen more easily. When I get to my air bearing project, I'm going to try using one of the off cuts of graphite to try bubbleing the Ag through.

Frankly, I don't think you'll need it with the induction furnace.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on January 26, 2021, 03:09:30 PM
I have seen it said that using a lid on the crucible can reduce the contamination  in oil and gas furnaces, you chaps ever use one?
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 26, 2021, 07:18:25 PM
I have yet to launch a capsule into space built with homemade castings.

Therefore extreme concerns over weight don't apply, and my aluminum castings are multiple magnitudes of degree heavier than absolutely necessary for their intended purpose. It's frankly a pain to cast too thin a piece, and mass and solidity benefits most machine parts I've ever made   as well as looking more substantial and aesthetic.

Occasional tiny pinholes requiring a magnifying glass to see in an aluminum casting are not therefore viewed as a problem. Now, I'm all in favor of others taking steps to perfect their casting, don't get me wrong. But I cast (as most other home shop sandcrabs do) with scrap, which is not devoid of corrosion, oil, dirt, or included steel clips (pistons, my favorite source of aluminum always has steel cast right into it). So the concept of avoiding contamination is doomed from the start. Luckily, it doesn't matter -- the contaminant either burns away into carbon dioxide or powdery dross (which actually protects the melt from oxidation), is fished out (clips) or skimmed off (dirt, oxides etc.) before the pour.

I did once put a crucible cap on an iron melt. Didn't seem to make any difference.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 26, 2021, 08:03:47 PM
re. caps....I should add, though, I think a cap would make sense on a brass melt to reduce zinc fuming and oxidation.

And I always felt, when melting aluminum in a charcoal furnace, that charcoal pieces which landed on top of the melt protected it from oxidation. Likewise coke on top of ironman's (luckygen1001 on YT) steel-to-cast-iron conversion melt video did likely reduce oxidation.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 27, 2021, 02:32:31 AM
No I’ve not used crucible covers in this context. (Yes in the lab on small porcelain crucibles): But  I do use a ‘cover flux’ - I say I do, it’s really’ ‘ I did’ as I doubt that I still have any left, there may be a tub in the cupboards of the foundry benches, memo to self to look !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 27, 2021, 05:42:40 AM
As I thought - the cover flux is long gone, but I did manage to unearth some treasures in my search for it:

A wooden 'snap flask' that I made using sash window catches

Several Sand Sieves in different meshes

Another Plate Pattern for brackets

And my Vacuum Pump used for de-gassing lost wax plaster moulds

Along the way I found a cupboard full of all sorts of dangerous chemicals and card board boxes so covered in mould I hate to think what is inside - the cupboard has been against a damp wall for years - must work out a disposal strategy  :bugeye:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 27, 2021, 02:00:25 PM
All very nice!  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 30, 2021, 06:18:31 AM
Yesterday I took delivery of five 8.5 kg ingots of pure aluminium from a re-cycler -  the analyser agrees that it's LM0 99 % aluminium, and today I've taken delivery of four Range Rover wheels weighing 80 kg so I'm all right for feed stock for a while once I've worked out how to cut the wheels up.

But what IS the alloy in Range Rover wheels ? The analyser says LM25 or 9% silicon with just a trace (0.37%) of magnesium which is fine - it machines OK but can be tough on tooling - but by adding the pure aluminium and a bit of copper I can get a really useful range of alloys and properties.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 30, 2021, 06:57:35 AM
Hi Andrew,

Very interesting to see the analysis of the Wheels! Cutting the wheels is a real problem. The last ones I did were quite small, so I was able to cut them using the Warco mechanical hacksaw, bolted down in place of the vice and for some bits a chop saw fitted with an Al blade. I have one of those RangeRover wheels waiting, they are big! A good method, which is not always very doable, is to heat them in a pit-fire until they are "hot short" you can then tear of bits with tongs. I haven't tried using a press, that way, they might end up a shape that is easy to saw! A bugger to clap down!

Cheers Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 30, 2021, 08:27:29 AM
I'm going to see if my Hypertherm 900 plasma cutter will do anything for me. It's specified to sever 7/8" mild steel and do proper cutting on 16 mm aluminium. I've only ever used it on mild steel, but I bought it from a ship yard in Wales many year ago where they used in on aluminium plate on a daily basis.

If I can cut the spokes off then slice the rim into sectors it may be the quickest way.

Alternatives are heat up in kiln until 'hot short' (energy intensive), Squash in 60 ton press (might get interesting as bits fly about). Squash in log splitter on tractor (same issues as the press) or wait for better weather and have a bonfire (metal contamination)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: NormanV on January 30, 2021, 08:42:26 AM
I have placed alloy wheels on top of a good wood bonfire and as they melt the metal runs out the bottom. I have no idea what it doe to the composition of the alloy but it does reduce the unmanageable wheels down to usable pieces that will fit into a crucible and can be remelted down, skimmed to get rid of the dross, and then cast into nice clean ingots. It's a bit of a faff but at the time my fuel was free.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on January 30, 2021, 08:55:05 AM
Plasma cutter should work nicely, I haven't used mine much for Al seems to cut more ragged! Needles to say mask up and if possible cut out of doors! Vaporised Al is really nasty stuff!

Hot short  and log splitter would be really good!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 30, 2021, 10:11:49 AM
So I tried the Plasma Cutter - just a trial to see how it went.

It has absolutely no problem cutting the required thicknesses, but I found  visibility through a welding mask quite hard due to the huge amount of glare from the cut. Also I had to stop a few times and clean the consumables as presumably 'stuff' had  lodged inside, also it was quite slow.

I had hoped to be able to use my Startrite "18V10" vertical bandsaw with a suitably coarse blade, however it seems that 18V8.5 would be a truer description as the throat is indeed 18 inches, but even stripping off the swarf blower assembly the greatest depth of cut that I can set it to is 8.5" unless I remove the upper blade guide, which would not be safe. - hmmph !

So it looks like it's the Plasma Cutter when the time comes.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: kayzed1 on January 30, 2021, 02:36:50 PM
JCB bucket i think :dremel:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 31, 2021, 02:05:15 PM
Andrew, I would think either a big gas welding torch or a Sawzall would do the job After all, aluminum can be welded with a gas torch -- the only problem is it's easy to melt through! Neutral flame though, not oxidizing. The other benefit is no arc re, optical filter type.

I have softened aluminum automotive bell housings outside in a wood fire and broken them up with a hammer, but it's dangerous.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on January 31, 2021, 02:36:34 PM
Thinking about it.....I think the sawzall would be my go-to for those wheels or heating over an open fire and breaking up. That last would probably be the quickest for all 4 wheels, otherwise it's a lot of cuts no matter what tool you use.

What are you thinking of casting, btw? Project(s)?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 01, 2021, 05:10:16 AM
Steve I agree about the Sawzall - I had intended to try my old one Sunday morning before I saw your post, but I got diverted onto other tasks. However this morning I dug it out, a cheap and cheerful copy branded 'Power Devil' (Screwfix I think) that I've had for at least 15 years, it has only seen occasional use as I always found it under powered.

Anyway this morning it got it's own back on me - I thought that it smelled a bit odd as I got it out of its case, and sure enough once plugged in and fired up it erupted it a shower of sparks  terminally :bugeye:  OK it was still crawling round but it's bin fodder - no point in even opening it up as it was always pretty useless !

So I've splashed out on a (hopefully decent ) Bosch  GSA1100-E 1100W corded job due for delivery on Wednesday. Even if it doesn't work for this task it's a useful tool in the armoury !

I don't think gas cutting would be very good - cutting steel, the steel itself is the fuel and burns intensely in the oxygen as the steel has relatively poor thermal conduction whereas cutting aluminium alloy the thermal conduction is so high that the alloy can't be maintained at burning point. I'm sure it would melt it's way slowly through but not as a proper cut.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 01, 2021, 11:49:58 AM
I agree that the torch method for steel depends on oxygen to burn the steel and that isn't applicable for aluminum. But I was thinking a large welding torch rather than a cutting torch, and no excess oxygen to form aluminum oxide.

But I also agree that I think the Sawzall would be a better bet -- of course the right blade will also make a big difference there.

And then there's the good old wood fire outdoors and club..... caveman method. Quite effective and cheery on a winter's day. Just don't hit yourself with a bit of shrapnel.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 02, 2021, 06:43:50 AM
I've decided to use an intermediate crucible when it comes to mould filling - pre-heat a crucible, fill it from the induction furnace, skim etc and pour.
 
So I need a pouring shank - all mine got given away. So make one - that was this mornings task.

1/2" Black bar perfectly adequate for these small crucibles but my blacksmiths hearth is not set up - how to heat it :scratch:. Not too convenient to use oxy-acetylene on long bars - although possible. Start off in the induction furnace - rapidly becomes impossible as the curve is formed. Shove it in the pottery kiln - ridiculously expensive in electricity.

Hang it - bend it cold!

So cutting an exact length of the bar to be the circumference at the height that I want the shank to sit, if I can get its ends pointing at each other and weld them firmly I should be able to bash it into a tolerable circle. It didn't come out too badly - be so much easier just to toss it in the hearth and do it hot, but you work with what you've got!

Once the ring was as good as it was going to be, I squashed it flat on the 60 ton press then welded a handle and a pivot - job done. The idea being that it will sit in a triangulated frame in front of the induction 'body' where I can tip the melt and do my stuff skimming etc.

Still need to work out how I'm going to pre-heat the crucible as I doubt that just putting it on top of the heating induction pot will be enough - damn the efficiency of induction melting !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on February 02, 2021, 08:59:56 AM
Have you got a weed burner? They aren't very efficient, but I've seen them used as raku Kiln burners!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 02, 2021, 09:25:38 AM
No Matthew - I did have but it's long gone.

But I had thoughts of resurrecting my Ceramic Chip Forge - not only could I have heated the ring up but it would do for pre-heating crucibles, and being gas powered with no coals, just ceramic chips, it's relatively quick to turn on and off. Currently in the depths of the tractor shed - I'll try and dig it out over the next few days.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 02, 2021, 11:18:04 AM
Looks good to me, Andrew.

I'm a cave man type so, if faced with that task, I would probably just build a wood fire outdoors from limbs I wanted to get rid of anyway, bring a couple of potatoes wrapped in foil, The steel goes in the glowing embers, and the potatoes go nearby in the cooler ashes.

Now I have a question re. ring shanks I've never seen answered -- and I've read a LOT of the available lit about casting and done a fair share it over the last 20 years myself. And that question is this:

How far up a crucible should the ring fit?

The reason I ask is because I have had crucibles slip out of the shank onto the mold when pouring the last of the melt. Not always but sometimes. And that is always an occasion for using words I'd prefer not to.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 02, 2021, 11:44:46 AM
That's a hard one to answer Steve as things don't stay the same size. The ring and the crucible alter as they heat and cool, and getting a 'good place' is a bit hit and miss. I aimed for 'sort of 2/3 rds up'  but you do have to be rather careful. Some designs have a hook over the rim of the crucible to prevent tilting but they are difficult to use as the hook is a loose piece.

You can adjust where the crucible sits by putting a few turns of soft iron wire round the ring of the shank.

Sadly we are so soaked here that my two bonfire sites are untenable. The one in the field is under a few inches of water, and the one in the veg patch is so soft you sink in up to your ankles !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 02, 2021, 02:34:01 PM
My old metalwork teacher would wander past when I was "adjusting" a piece of metal in the vice, with a big hammer, and whisper "All cold blacksmiths go to hell" God bless you Spearmint Jim Wrigley for passing on to me an undying love of metalwork!
It looks good enough to me Andrew! I am in the same boat with my forge, I am going to have to rejig the flues in spring.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 02, 2021, 02:59:59 PM
Hmmm, I don't think that expansion of the ring and crucible probably make much difference to the slipping problem as the crucible will settle to wherever it needs to maintain a slip fit . Yup I do know the fit can be adjusted.

For me the question still stands: where should it properly be located when making one? Is it half way up, two thirds, etc? I wish Ironman still visited here, as I wouldn't doubt that he has a useful opinion on it.

And also I, like you, Andrew, have made shank rings out of round bar and about 2/3 up which felt right as a mere guess. But I experienced the problem and ruined a pour. I do wonder if round bar contributes to the slip out problem. Would, for instance, square section bar be preferable? Or even flat stock? Would it be an advantage if that were shaped to a cone segment? Much to ask about this particular topic!

I suppose a shank could be tested in advance over a padded surface to protect the crucible. That might have been smarter of me than finding it out during pours. Also to mimic the real action maybe a few largish ball bearings poured in the process to mimic the molten iron emptying out and shifting the balance.

I should confess that I eventually gave up on ring shanks altogether and just poured directly with the tongs I made. But I'd still like to know the solution to the problem.

Edit: Okay, I'm going to throw out a new (for me ) guess, that actually the ring should be located nearer the bottom end of the crucible than its balance point when on its side. Theory, mind you, not necessarily reality.....

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: millwright on February 02, 2021, 04:59:57 PM
Andrew,
 is the chip forge an ex schools flamefast one? a single or a double one?

Phil,
the term i heard often as an apprentice was, cold iron blacksmiths go to hell. I had a chap working with me on a job outside on a very large steel dust cabinet that filtered the air from our shot blast unit, a very large one. The job was to open up the cabinet and remove the filter bags and fit new ones, the problem being that they hadn't been changed for too long, the 4 cabinet doors were bolted up on 1/2 bolts at about 12" spacing and the doors about
 6ft X 4ft absolutely rusted solid, quickest option knock them off with a hammer and cold chisel, i started on the first one with John watching me before he stopped the hammer on my backswing and told me to sit and watch, he said he couldn't stand and watch me doing it with hammer in my wrong hand, i'm left handed, most of the bolts he got off in one hit and the doors were off in no time without him breaking into a sweat.  it was after he had finished i found out he had been a blacksmiths striker, his wrist and arms were twice the size of mine.

Sorry Andrew, carry on.

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on February 03, 2021, 03:50:36 AM

Now I have a question re. ring shanks I've never seen answered -- and I've read a LOT of the available lit about casting and done a fair share it over the last 20 years myself. And that question is this:

How far up a crucible should the ring fit?

The reason I ask is because I have had crucibles slip out of the shank onto the mold when pouring the last of the melt. Not always but sometimes. And that is always an occasion for using words I'd prefer not to.

Round sections are much easier to make, but flat, conical rings with the same angle as the crucible will hold better. Two thirds up the crucible, with the ring near the beginning of the bulge. Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2021, 05:28:37 AM
Matthew yes some of my previous ones were made from flat bar of about 1" x 1/8" and bent on a taper which is easy to form if you have a forge and a big enough blacksmiths cone. My cone would 'just' be big enough for that particular crucible but useless for the big ones I used in my pit furnace.

John, the ceramic forge IS an ex school single burner one. It along with my coke forge were of course buried deep in a corner of the tractor shed and I'd thought it was going to be a major pain extracting it, but in practice I just had to move two tractors and I was able to move it to a more accessible place where I can get the forklift at it. Not doing it today as (naturally!) it's pouring down and has been all morning and there's no point in soaking it (or me!)

Let's hope that it still works. It's gas regulation is odd in that it uses a strange 'zero demand'  or maybe 'zero pressure' valve - I don't remember which but I know that it gave issues 15 years ago and I had to replace it as it had jammed from lack of use sitting idle for too long.

Anyway the new Reciprocating Saw is due for delivery in the next hour, so I have a date with some alloy wheels !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2021, 09:35:24 AM
The rain slackened just before lunch so I decided to fire up the fork lift and shift the DS130 ceramic chip forge at least into the stable, and if possible as far as the foundry (fork lift won't do the 90 degree bend up to the foundry so the last leg is 'push power')

Well with the very high humidity the propane engine of the forklift was extremely reluctant to start. I did eventually get it firing on two cylinders so putting a bit of heat into it and after about ten minutes off we went.

Having just got it running reasonably the delivery of the Bosch Reciprocating Saw arrived so a quick trot across the farm yard with the DS130 loaded up, and I popped it down at the far end of the stable. By this time the rain was back  :bang:

Never mind, the show has to go on. Quickly returning the fork lift to the Tractor Shed and locking up it was a case of man handling the DS130 up the slope and over the threshold strip of the foundry where it now sits. I did manage to prove that the blower fan still works and the pair of solenoid vales at least click when powered so there is the possibility that it works !

After a quick lunch (Welsh Rarebit)  I was back out to try the new toy. I have to say that it performed very well. It came with  a nice 'progressive' coarse metal cutting blade (S123XF must order some more!) that slices nicely through the rims though it does take kindly to a squirt of WD40 as a lubricant going through the thicker bits.

It's definitely the way to go (Thanks Steve for jogging me!) and far less mess than the plasma cutter or bonfires etc. It also allows me to store the alloy as rims and cut off what's needed for a particular job.

Time to put the old dead Power Devil one in the bin !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 03, 2021, 10:52:52 AM
Great to hear about the forge and rim cut successes, Andrew.   :beer:

Quote
Two thirds up the crucible, with the ring near the beginning of the bulge. Cheers, Matthew

Unfortunately, Mathew that's the fit I had during a few crucible drop outs, at least with a round sectioned ring.

The problem seemed to be that, as I turned the ring past vertical the crucible was able to pivot within the ring, due to the taper, and then slip out. So there were two movements. First a pivot in the ring, and second a slip out of it. I'm now wondering if maybe it was a result of different shaped crucibles that I tried. The bilge was not always as pronounced, nor was the taper the same on all I tried. That was pouring iron, btw.

Hmmmm, I might have to do some experiments and revisit using ring shanks. I'll stop cluttering up your thread here Andrew and open up a new one if I do.


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on February 03, 2021, 11:03:17 AM
This guy carries and pours his crucibles with a claw-type effort that grips the rim of the crucible. Around 17 minutes in.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2021, 11:19:34 AM
That's a dangerous way to carry a crucible. A friend (George) of mine and myself were casting bronze years back, and with an 'unconventional' way of carrying the crucible we did something similar with tongs. A big chunk came out of the wall of the crucible, we dropped the lot and the bronze went everywhere  :bugeye:

By one of those co-incidences a huge amount of it flowed round and under that very same ceramic chip forge - very fluid stuff bronze - and I had the devil of a job extricating the base of the forge from it when it had cooled.

Fortunately we both had heavy leather boots on at the time and no one was hurt, but not an experience I'd want to repeat.

(I know Iron Man says crucibles are very tough - I'm sure some are - then there's the others !))
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 03, 2021, 01:42:21 PM
I cannot claim any experience in this area, but would it not be possible to weld a flat bar with a small turn on the end to the outside of the ring, in such a way that the ring could be sat at a slight angle, the crucible placed in it, and then the shank lifted at an angle until far enough up the crucible for the turn to slip over the top of the crucible as the shank came to its stopping point on the crucibles taper.  Am I explaining that well enough to get the idea across?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2021, 01:54:35 PM
A hook loosely pivoted on the ring outer diameter and lifted over the edge of the crucible once it's in the ring works well to stop the accident that Steve had. But in my experience fiddly things like that are bound to go wrong 'in the heat of the moment' when you've just lifted the crucible and are manipulating things without help. Different matter if there are two of you and you rehearse things properly before you start.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 03, 2021, 02:29:47 PM
Agreed Andrew, I'd not like to flip a hook on an iron melt -- there's time pressure as well when doing relatively small home shop iron melts (A6 size in my case) because cooling is rapid. Also you're trying to slag it then, and I can imagine tangling up with a hook, or getting slag all over the mechanism while doing that.

I just think that this should be a simple matter of figuring the ring problem out for myself -- rings work for others, there was obviously a slight difference for my setup at the few times it happened for me. I just have to figure out what the actual cause was. Again, also, it happened maybe 3 times total, and only during Iron melts -- I don't use a ring shank otherwise.

I do think just trying it with a cold crucible over a cushion, and/or with sand in the crucible will reveal the cause and probably a solution.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 04, 2021, 02:36:07 PM
yes, I have seen the hinged version, and various other methods of retaining the crucible, all looked time consuming and  dangerous to me. what I am suggesting is a fixed hook, welded to the outside of the shank ring, so that the crucible does not touch it when the shank is at an angle, but the hook naturally falls onto the top of the crucible as the  shank  gets to the stopping point. If I had a crucible I would make one! I could do with one anyway to reduce my alloy collection to usefull ingot size in the forge. Maybe I should order one?
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 04, 2021, 04:58:27 PM
Opening a separate topic re. ring shanks in "Metal Stuff" section of the forum.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 06, 2021, 10:48:15 AM
Various bits of plumbing arrived this morning allowing me to connect the Ceramic Chip Forge to propane. The 8 mm flexible gas pipe had perished, and goodness knows what happened to the female quick disconnect wall fitting so this is what I had had to order.

The gas cylinder is one I brought from Bromley 13 years ago and still has a little left - it's a 47 kg cylinder (tare 40 kg) and my bathroom scales say it now weighs 56 kg so 16 kg of gas left.

Finally the cylinder will be permanently fitted in the Cylinder Cage that I made last year, but to avoid drilling holes in the wall just for a test I brought it into the foundry.

To my amazement all seems to work, but I need to find out some how what delivery pressure it expects. It has a pilot light like a bunsen burner on the end of a pipe, a blown air / gas torch on pipes that are far too stiff for comfort, and of course the forge itself which is rated at 22 kW.

It lit up OK and I tweaked the gas pressure to a flame that looked reasonable and let it cook. Ten or fifteen minutes later I had some 1/2" bar glowing at a nice forging temperature  :ddb:

So it just needs a permanent site and fixed plumbing, though I am very tempted to leave it on it's wheeled skid for flexibility.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 06, 2021, 11:00:45 AM
Well it helps to read the rating plate - 20 mBar !

It is marked for 'natural gas' ie North Sea Gas but I can't remember if it had been converted to propane or if I found it satifactory without conversion. BUT I did find a record of correspondence that I'd had with another shed dweller describing the difference in size of the jets so I must measure them at some time.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 06, 2021, 02:26:12 PM
www.flamefast.co.uk, theyre still in business, and apparently expanding! That forge looks very good, and fast......and smokeless! Lucky man!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on February 06, 2021, 07:52:18 PM
I’ve got this chart if it’s any use to you.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on February 06, 2021, 11:29:41 PM
Never seen such a thing.
Propane forges are very handy, but often challenging to fit anything other than straight bar.
How hot can it get?

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 02:19:56 AM
Years ago as an experiment I did some hammer welding of some bar like that illustrated glowing above, and it was hot enough!

Leave a bar too long in and you can suffer the indignity of melting the end off !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 04:42:25 AM
Time to investigate the Flamefast DS130 Main Jet:

It nestles behind a 1/2" BSP plug blanking off one branch of a Tee fitting, and the jet is long enough to project into the Venturi chamber allowing the passing forced air to draw gas through the jet and from the 'Zero Pressure' valve. I don't think I've had this out before as it wasn't familiar as I dismantled it.

Anyway, using drill shanks as precision measuring tools (!) it measures as 4.1 mm - this doesn't correspond to either of the two possible sizes cited by the late Tim Leech in the document I posted above where he says #28 (3.56 mm) for Propane and #17 (4.39 mm) for Natural Gas

. . .odd  :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on February 07, 2021, 05:30:45 AM
Half way in between..
Sounds like a 'universal' option..

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 05:50:02 AM
Funnily I just voiced that possibility to the wife  :clap:

I can't think Flamefast would have sold it with a universal jet and still labelled it for Natural Gas, probably more likely some one has modified it over the years, after all it's 38 years since it was made - lot's of time for fiddling by someone trying to get more oomph out of it!

Frankly as long as the flame is OK I don't suppose it matters much - I need to investigate the torch and bunsen pilot light though as they are quite fierce.

The other variable is supplied gas pressure - I'm just setting the regulator on the cylinder to a low PSI, the label says 20 mBar which is 0.3 PSI, BUT all gas supplied goes directly to one big internal regulator which I haven't tweaked so presumably it's set as per Flamefast intended.

There are test nipples on both the inlet and outlet sides of this main internal regulator and I do have a suitable gas rated manometer (from when I did a CORGI course years ago) so as long as it's rubber tube hasn't perished too much I can measure it, but not knowing what pressure the internal gas plumbing is supposed to be anyway I haven't bothered.

. . . life is full of conundrums  :med:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on February 07, 2021, 06:25:54 AM
Does the jet size and pressure affect the flame properties in the same way as an oxidising/reducing flame from a gas welding torch or is it just a matter of efficiency?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 07:29:31 AM
Effectively yes Pete, you need the right raito not to get a sooty flame and get a hot enough flame.

These things never go smoothly do they - I just came out to the workshop to try and free up the volume control on the gas torch - just a simple taper duel gas cock - dismantle, clean, grease, put it back together and test. Simple, except when I came to test, the gas interlock valve won't operate - no gas - no flame  :bang:

Now the two valves, the interlock, and the zero pressure are made as a single diecast  block with two coils removable to operate them. This unit gave me trouble years ago, and I sourced a new valve block, but it turned out just one coil had failed. So I have a block with just one coil. Wiring the spare coil to a mains lead and with everything else turned off I was able to prove that the lower valve unit wasn't operating. Nice click from the upper one, just humming from the lower with the same coil used each time, so the lower valve is  stuck in the closed position. Gentle tapping and warming have failed to free it so it looks like I'm going to have to fit the spare I bought all those years ago.

The plumbing isn't conducive to removing it as various elements haven't room to rotate due to the outer cover. One pipe has a knuckle joint so easy to remove, but the other doesn't !

- lunch time. I'll have a go after lunch.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: AdeV on February 07, 2021, 07:30:08 AM
What's the jet size for Butane? Would that be somewhere between propane & NG?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 09:18:25 AM
Interesting point Ade - I don't know  :scratch:

So pulling the front casing off I was hoping to reveal a union to allow me to pull the pair of valves out in a civilised way, but sadly none were apparent. so I am going to revert to drastic measures and saw off the pipework, and when I re-make it insert a standard pipe union where the stubs of the cut off pipe will be.

1/2" BSP pipe union ordered - should be here Tuesday meanwhile I'll get on sawing off the pipe. No doubt filings will fall into the valve but it's being replaced anyway so hey - ho !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 07, 2021, 09:48:46 AM
Beware Andrew, when I first fired up my Flamefast brazing hearth using a variable blowlamp regulator, I got a roaring blue flame, and lots of heat, but after a few minutes my CO alarm went off, warning me of incoplete combustion and potential death! I got the right regulator as recomended by Flamefast, and it made a huge difference! Drop them an email, their tech dept are very helpfull
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 10:16:45 AM
Good point Phil, although this is the same regulator that I used for years before I moved - googling tells me no more than 35 mBar at the input to the forge regulator for Propane, and it seems that my manometer tubing IS still OK. I'll check it's set up when I replace the gubbins that I've just sawn off. Mind you, incomplete combustion should have given you a yellow flame (carbon particles in the flame) not a blue one.

I've just taken the reciprocating saw (newly acquired - thanks Steve !) to the pipe work and sliced off the offending bit that I couldn't unscrew.

Now remember I tapped, nay even BASHED the unit while I was testing it hoping to free it up into a working state - now needless to say having used the reciprocating saw on it's pipe guess what - it works ! I'm not entirely surprised.

So I think I will put the original back, but it will have to have the union fitting of course, as if it sticks again it will only be a union and a pipe clip to remove it for replacement.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 12:02:27 PM
Following Phil's regulator comment I've been doing a bit of 'internet research' this afternoon.

Firstly, the forge is rated at 22 kW which is equivalent to 1.6 kg/H of propane - many regulators are marginal being rated for 1.5 kg/H and some only 1.0 kg/H.

Secondly most propane appliances expect 37 mBar input pressure so it's reasonable that this the forge when converted would be the same.

I have no idea of the rating of my regulator, but if it and it's pipework (8 mm) are not capable  of maintaining 37 mBar at the forge input I'll replace it.

If the regulator isn't 'up to snuff' to supply enough throughput the output pressure will fall with demand, and owing to the way the forge works drawing gas by an air operated venturi the gas / air mix will be too weak, so combustion should be complete anyway.

Internally the propane is further regulated down, and while this second regulator is on the bench I'll see if I can measure its output pressure.

 . . .now to seek out a drop of dye or proper ink to colour the water in my Monument water gauge so I can see the level!

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 07, 2021, 03:14:17 PM
Re the yellow flame Andrew, yes, that is what I would expect, but my hearth has a 4psi air blast and although it produced a blue flame, it seems there is a cold centre to the flame, as if the gas is fed to the nozzle round the outside, and the air in the centre. If you look at the nozzle, this seems to be the case.. It was fairly belching out CO, and only took a few minutes to set the detector off, whereas now, with a 37mbar regulator the flame is much hotter, and no CO is detected! It had me scratching my head because as you say, it doesnt make a lot of sense, but it seems to work very well now.
Phil.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 07, 2021, 03:33:48 PM
Phil can you confirm that your new regulator is definitely a 37mBar one? Have you any idea of it’s rated through put in kg/H and what does the rating plate of the hearth say about heat output in kW ?

You’ll be pleased to hear that I’ve ordered a couple of CO monitor / alarms !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 08, 2021, 09:39:22 AM
Its this one Andrew
https://www.ebay.co.uk/itm/IGT-37mbar-PROPANE-GAS-REGULATOR-WITH-PRESSURE-GAUGE-2-M-HOSE-KIT-WITH-2-CLIPS/163753022109?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649. All the other information is at the workshop and we are having a snow day today, so I will get it as soon as I am back there. The torch on my hearth is a flamefast T4.
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 08, 2021, 09:43:31 AM
Well, developments of sorts. I spoke to Flamefast in Warrington, and it turns out that the 'regulator' that all the input gass passes through is not a regulator but a non return valve. This would explain why when I tried to measure it's output pressure having made a 'mock nozzle' of the same 4.1 mm diameter as is currently fitted I got the same pressure in input and output! Apparently all the internals when on propane are supposed to run at 37 mBar.

In the absence of ink I used some red food colouring dye in my water manometer to make the level easier to see, but being intended for natural gas it only goes up to 30 mBar !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 09, 2021, 07:17:30 AM
My 1/2" BSP taper union arrived this morning so first job was to work out how much longer the union with it's stubs of pipe will be compared to the length of pipe that I cut out.

Answer = 20 mm - now this means that the dual valve unit and non return valve will sit 20 mm lower in the machine, but they are supported on a saddle clamp that needs lowering by the same 20 mm.

Easy - its a 'kit of parts' with the lower fixing being tapped 1/4 BSP as is the lower half of the saddle, and they are joined with a bit of 1/4" BSP pipe. Pipe needs cutting shorter by 20 mm and threading. In practice I did the threading first to use the existing thread as a 'starter' for hand threading.

All went well. Gas joint threads sealed with Loctite 542 and it fitted nicely. Once the Loctite had 'gone off' it was time to test it.

Did it work . . . NO  :bang:  The solenoid valve had jammed again. Never mind it's now SO easy to remove, just undo the union, release the saddle clamp and out the assembly comes.

So I test it on the bench with every intention of putting in the new one BUT the bally thing works perfectly. so for now I've re-installed the assembly, gassed it up and proved that it works. If it sticks again I'll swap it out for the new one.

Still no word from Flamefast as to what the correct jet diameter is but I've done a sketch of the jet so that I can make one to size without further dismantling. It's a bit of 1/2" brass bar tapped M12 at the business end where the jet hole is, and drilled 8 mm down the rest of it's length. I'm out of stock of 1/2" brass bar but I do have 1/2" hex which will fit so that's what I'll use when I know for certain the right size.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 10, 2021, 10:11:13 AM
Still no word from Flamefast despite another nudge so I thought that I may as well just go ahead and make a new main jet from the data I got second hand back in 2004. It calls for a #28 drill which I don't have so I erred on the next size down in my tenths metric set at 3.5 mm. Better too small as I can always open it up.

Easy enough bit of turning, and it fits nicely and works. Output of the hearth at the same pressure is naturally a bit less than before as you would expect. I have a tweakable regulator fitted at the moment but have a proper 37 mBar pre-set high capacity one on order.

Phil I didn't order the one you linked to - enlarging the picture it is rated at 1.5 kg/H - this hearth takes 1.6 kg/H so close but too marginal - the one I have on order is  4 kg/H rated so comfortably in spec.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on February 10, 2021, 11:12:17 AM
Andrew does your old jet have a taper on the inside towards the orifice end?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 10, 2021, 11:46:00 AM
Not discernibly Steve, it steps from 8 mm (65 mm deep)  down to jet size (was 4.1 mm now 3.5 mm) jet bore being 25 mm deep.

The thread strangely is M12, I'd have expected it to be BSP of some size, so I have  a feeling things have been re-engineered previously
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 10, 2021, 12:27:29 PM
Interesting Andrew, I will have to check the spec on my torch, I may have a slightly too small throughput!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 10, 2021, 01:29:53 PM
22kw equates to 1.65 kg/H iirc so it depends on the heat rating of your torch
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 11, 2021, 05:33:13 AM
Still no word from Flamefast re jet sizes so it looks like I'm on my own there !

So I decided to get on with a bit of 'routine maintenance' on the hearth. The gas / air mixture enters a chamber below the hot bit, the top of which is a firebrick circular tile pierced with a humongous number of 1/8" holes for the mixed air / propane to pass through into the ceramic chips. I know from previous use that these holes get blocked up with debris from the forging and the ceramic chips themselves. Doing this exercise when I first got the forge I ended up buying a new pierced tile from Flamefast as there were so many that I couldn't unblock. This time I managed to clear the vast majority with a short length of 1/8" silver steel gently tapping with a light hammer. Some however where beyond clearing. I did this exercise with the air blower working to try and keep as much debris as possible out of the lower chamber.

The tile is set in fire cement, but I notice that although its periphery is well sealed, the four 'quadrant tiles' that form the actual bowl of the forge are not well sealed one to the other. I've placed an order for fire cement to resolve this - due Monday /Tuesday.

I'd hoped to be able to test the burning of the gas with no chips in place however it seems that the chips are needed to anchor the flame to the burner as the flame seat lifts off the holes in the tile.

Incidentally those chips are ridiculously expensive. About £90 plus VAT and carriage for enough for the forge. I can't believe that they are SO special. What you see in the bucket (picture below) are ones I bought new in 2004 so they last OK but there are always losses as they cling to items heated up, particularly if there is any flux present.

I do wonder if the ceramic pebbles sold for gas coal effect fires could be pressed into service. They are far too large but I've no doubt that my 60 ton press would be happy to help reduce them to chips !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 12, 2021, 07:22:42 AM
The Fire Cement was delivered today - early so that's good. KOS brand - I can remember using this stuff to embed nichrome wire coils to make power resistors back in my youth !

So - blow out the dust from the joints between the quadrant fire bricks, dampen the brick with a wet brush, and force the fire clay as far as possible into the joints. Make tidy with a wet brush, and I also did the circular pierced tile to quadrant brick joints.

All this is to seal the plenum chamber beneath the pierced tile so that the propane / air mixture only comes up through the pierced holes and not the cracks.

Next job is to sieve the remaining ceramic chips to remove the dust particles before they go back in the hearth bowl.

I'll leave the fire clay a few hours to air dry before a gentle firing to set it. There will undoubtedly be cracks as it fires up but it will be better than it was !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 12, 2021, 09:20:27 AM
Sieving the ceramic chips produced quite a bit of 'fines' and several coagulated lumps which I discarded and re-loaded the forge bowl with what remained.

When I lit up I was surprised how much steam it produced - 1/4 of a cup at the most was used in moistening and smoothing the fire clay, and I suppose that the fire clay itself contains water. At this stage the fire clay isn't being subjected to any great heat as where it was applied is several inches away from the hot chips. My idea being to heat the chips and let the warmth spread gradually to the fire clay.

Previously there had been evidence of combustion in the rear quadrant joint (see picture with burn mark on the paint) I'm glad to say that is no longer happening and the steel body stays cool as it should.

Having cleared the perforated tile holes there is a noticeable change in the shape of the hot area of ceramic chips - heat is over a much wider and more even area for a given gas pressure.

So was it worth all the hassle - yes I think that it was even though all I intend to use it for is pre-warming crucibles !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on February 12, 2021, 07:55:57 PM
Looks good!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 13, 2021, 05:31:24 AM
Thanks Tom  :thumbup:

The 'High Flow' propane regulator arrived this morning. Output supposedly 3/8" BSP and is printed on the outside of the box but when I looked at it and tried a 3/8" BSP fitting it wasn't ! Delving into the box the instructions say 3/8" NPT

Now 3/8 BSP is 19 TPI and 3/8" NPT is 18 TPI - they are NOT compatible when hoping for a gas tight seal  :bugeye:

A pain as I've had to order up an NPT hose tail, and NOT the sellers fault as Silverline had marked the box BSP - some one has screwed up !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 14, 2021, 10:53:42 AM
Time to replace the hoses on the Torch associated with the Ceramic Chip Forge. It occurred to me that I hadn't taken a picture of it burning previously then I realised that it was that the old hoses were SO stiff and inflexible I couldn't hang it on it's allotted hook for the picture. Not so now - I'm using 8 mm i/d propane hose for the gas and 10 mm for the forced air. These are close but not identical to the originals which are undoubtedly Imperial sizes.

It was such a struggle to get the fittings onto the hoses that I had to resort to unusual means. I'd tried loads of lube and boiling water to no avail, what I wanted was something hot and slippery - a cup of very hot oil to dip the hose in. Searching about for a suitable flameproof metal container I settled on a 'turn over handle' that I'd made to set the timing on the Thwaites dumper truck. Set in the vice. 3/4 filled with oil and heated to 125 C with a blowlamp it worked quite well. Hold the hose end in the 'cup' let the rubber heat up, push it on. Still quite a struggle but far easier than using hot water !

I'm still waiting for the proper double ear 'O Clips' for the 10 mm hose so that has temporary ones on at present. Torch now easy to manoeuvre with no more fighting the hose to get it where I want it.

There is one 'strangeness' that I want to get to the bottom of. If the hearth is burning there is no gas going to the torch, despite the fact that there is a direct connection from the gas supply to it (via a ball lever valve)   I have a feeling that maybe it is because the gas to the hearth is drawn into its burner by air flow through the venturi and perhaps the gas pressure in the internal plumbing is pulled down sufficiently that air is drawn in via the torch gas jet. This effect is also exhibited by the 'Bunsen' pilot jet.

When my 'High Flow' regulator is plumbed in (awaiting an 8 mm 3/8" NPT hose barb) maybe this symptom will be eliminated.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 14, 2021, 12:29:13 PM
Very interesting Andrew, that torch looks a lot like mine, and yet the flame sems to be reversed, you have a flamein the centre, whereas I have a flame round the outside? I wonder if some idiot at this and has the hoses reversed?
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 14, 2021, 01:20:26 PM
Phil the air hose is fatter than the gas hose so hard to get them wrong :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 15, 2021, 06:51:20 AM
I am going in this morning so I will check, but I think mine are the same diameter, and both RH thread on the torch end. My torch seems to be blasting air out of the centre hole, producing a cold core to the flame. Any road up, summats not Jannock, as my old boss used to say, i will check it out and let you know!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 15, 2021, 07:06:03 AM
Interesting - the metal tube bits of my torch have the hose barb grooves directly into them so no screwed fitting as such - just push on and crimp. Out of the DS130 the gas is 1/2" BSP male cone and the air is 5/8" BSP male cone. (Don't often see 5/8" BSP and this one is an adaptor down from a 3/4" lever ball valve)

There doesn't seem to be a jet as such on my torch - the burner end is a wiggly steel shape that unscrews and apart from the inbuilt taper control knob that does air and gas in separate sections there seems to be no restriction other than the size of the tubes that the torch is made from.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 15, 2021, 02:49:33 PM
NAH MATE! my imagination, you can't get the gas and air pipes swapped over, they  would fit, but then there would be no gas at the pilot! obvious if you have half a brain! My hoses are the same size, and have threaded couplings onto the torch, and it has also just been rebuilt by Flamefast, who recomended the 37mbar reg, but made no mention of throughput of gas as I can remember, I will check tomorrow and take pics if I get chance, but tomorrow is Holbrook bed collection day, so it will be fraught! Wish me luck!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 18, 2021, 05:39:07 AM
At last I've heard back from Flamefast - apparently 3 mm is the jet size for propane - the one currently fitted is the one I made at 3.5 mm so I'll make another in due course.

(Note: The torch is rated at much the same output as the forge so I used it for the following tests)

I've managed to get my hands on a suitable manometer to cover the propane (37 mBar)  pressure range so can do some proper diagnosis on the issues. Setting my (probably low flow rate but adjustable) regulator to 37 mBar  with no gas flow and then setting the torch burning rapidly demonstrated the problem. The gas pressure dropped dramatically to barely 1 mBar (though the torch burnt well!)

Re-adjusting the regulator so that the pressure returned to 37 mBar gave a huge flame and insufficient air for the amount of gas, so luminous, however throttling the gas down with the lever ball valve on the manifold I could restore the flame to a very acceptable shape and colour.

Of course turning off the torch increased the gas pressure well above 37 mBar (blowing my red - dyed water out of the manometer !)

So I definitely need to increase the feed pipe bore and get the high flow regulator fitted. The feed from regulator to the  forge is currently 8 mm and I have 13 mm on order with associated fittings to allow the high flow rate regulator to be used.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 19, 2021, 06:53:15 AM
The hose and fittings have arrived to fit the new 'High Flow' regulator and a fatter feed pipe from the regulator to the forge -13 mm as opposed to 8 mm -
This represents a large increase in delivery area - 50 mm increased to 133 mm

As expected the propane pressure now stands up better to the flow of the torch and the forge, but still dropping to about 30 mBar.

However I notice that there is obviously a leak between the perforated ceramic tile that is the actual burner and the pan or plenum chamber below it as gas / air mix is leaking out below and igniting at the side of the quadrant tiles - this is bad news as it means digging the pre-formed tiles out of their bedding cement to see what is going on.

This ceramic chip forge is being a bit of a pain (to say the least) taking far too long as it is really a diversion off the 'main event' which is the Induction Furnace, however I don't feel that I can leave it as it is and must bite the bullet and fix it.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Muzzerboy on February 19, 2021, 10:30:54 AM
FWIW, there's "25KG 1400DC Dense Castable Refractory Furnace Kiln Forge Lining" on homeworkshop.org.uk at the moment. No idea if that's even remotely applicable, or pricing or anything but thought I'd mention if you haven't seen it.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 19, 2021, 11:16:29 AM
Thanks Murray - as you will see from the pictures below I've managed to remove the perforated tile without breaking it, although I've yet to clear about 20 holes that are refusing to be poked free. Perhaps a carbide drill will work if I can find any long enough and thin enough (1/8" x 2")

The fire cement / grout or whatever it should be called that surrounds the tile and seals it to the 'quadrant tiles' and the plenum chamber is very friable and crumbly - probably intentionally to allow for expansion and contraction. Whatever it is it's the correct stuff that I bought from Flamefast years back. The tile sits on a fibrous substance that sits on the steel of the plenum chamber. Now I (perhaps foolishly) didn't replace this all those years ago and it has totally fragmented. Whether it is intended as a gas seal or just as a thermal cushion between the steel and ceramic I'm not sure. I have a call in to Flamefast but they've not come back to me yet.

It is possible the 'gasket' is just Kaowool  or similar.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 19, 2021, 12:14:02 PM
Blowing through the 'perhaps Kaowool' tells me it's far too permeable to be a seal so I think that it is just a thermal barrier and perhaps also an 'expansion cushion'  between the steel and ceramic bits.

The good news is that I have managed to clear ALL the perforations in the tile by extremely gentle and slow application of an 1/8" HSS jobber drill. Much to my surprise it slowly dislodged material that was too stuck for an 1/8" punch and hammer to move.

(anyone want a grossly maltreated 1/8" drill bit  :clap: )

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 19, 2021, 02:27:10 PM
Well Done Andrew! not an easy task without a breakage! I have today dug out the paperwork which came with my torch when it was rejigged for propane/butane, and the torch demand is 1.66 Kg/hr and output 23.5kW for the T4 torch.

Phil
Edit, this effectively puts me in the same boat, except that the T4 operating pressure is 35mbar, not 37 will that regulator be ok or not? For what they cost, I will buy a higher throughput 35mbar one!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 19, 2021, 02:51:18 PM
Thanks Phil,

Those figures tie in pretty well exactly with what I was given by Flamefast but means that your regulator is marginal at 1.5 kg/H
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 19, 2021, 04:16:22 PM
I now find that nearly everyone sells 37mbar, but not 35mbar! Will look again tomorrow, Time for T and bed!!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 19, 2021, 04:21:04 PM
Phil, they probably say 35 mBar to allow for a bit of loss in the pipe due to the flow - 2 mBar is peanuts.

But do you have any way of measuring the actual pressure when in use. I expect that it'll be lower than you expect !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 20, 2021, 06:58:03 AM
Being a Saturday no more progress in sourcing the correct bedding compound for the tile - it's a very light, crumbly white material rather like Plaster of Paris but softer. I'm fairly sure that the gasket / cushion under the tile is a KAOwool type and that can be sourced easily in suitable sheets.

As for the bedding compound whatever I use needs obviously to stand up to the heat, give a good seal to the gas / air mixture between the plenum chamber and the perforated tile and yet be able to be dug out in the future to replace the tile (which really is a consumable). There are various high temperature silicone seals that look good on paper but I've never used them. However all the ones I've found say (oddly) not to be used as a gas seal despite being intended for flues  :scratch:

I thought I'd try and 'size the problem' by laying the tile back in unsealed and ungrouted and see how much was actually escaping. In the picture you will see a blue fringe where the escaping gas / air mix has ignited, though interestingly now the flames no longer lift off the tile seat - this is probably due to the new regulator.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 20, 2021, 07:06:23 AM
This stuff may be suitable

(comments welcomed!)

https://www.mapei.com/gb/en/products-and-solutions/products/detail/mapeflex-firestop-1200-c
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 20, 2021, 12:53:19 PM
Andrew, could that bedding material be there to dissipate the gas so that you get a flame out of every hole? difficult to photograph I know but it doesnt appear that the outer holes are burning? I have seen this dissipation layer in an ornamental gas fire we had which was supposed to look like a log fire. Also seen somwhere, gas burning on the surface of a bowl of sand which acted as a dissipation layer, but can't remember where. If so, would a layer of fiberglass or rockwool work?
Phil
Edit, where did you get your 4kgh regulator from?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 20, 2021, 02:03:08 PM
Phil, as far as I can recall from about 20 years ago the layer under the tile was washer shaped with a 6" hole in the middle leaving all the holes exposed, and a 12" outer diameter matching the tile. But it had totally fallen apart as I didn't renew it all those years ago. I'll try to get an original one on Monday.

The regulator was from eBay - It's a Silverline 997865. I got it from a seller that just had the one, and it does seem that there is more than one version as some say 3/8 BSP and  some 3/8 NPT and are undescisive as to whether it's LH or RH. Mine was NPT RH and cost me the princely sum of  £7.95 !

In normal use the ceramic chips defuse the gas / air mix of course and add a bit of back pressure hence the outer holes come into play. In the picture, the holes opposite the pipe leading the gas / air to the plenum chamber are taking most of the flammable stuff.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 20, 2021, 02:52:05 PM
Jammy dog, I had to pay £17.95 for mine!!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 21, 2021, 06:13:45 AM
They are only a tenner iirc anyway Phil.

So not being able to get on with the hearth itself due too lack of materials I decided to re-make the coupler that joins the torch gas lever valve to the torch flexible hose, but incorporating a choke or jet to reduce the gas flow. As it was, if the gas was fully on a dangerously long yellow flame was produced. The 1/2" BSP lever valve  presents a female socket, and the original adaptor was a short stub of 1/2" pipe threaded both ends with a slight socket boring into one end to receive the 60 degree male cone on the flexible pipe. A bit crude and of course 'full bore' at 1/2".

I made one from a bit of hexagonal steel which gives the advantage of flats to put a spanner on when tightening. Jet end drilled 3 mm, female cone end drilled 6 mm then bored to give a good area of 60 degree taper with a big centre drill (BS7 3/4" Body).

Now if lit with cocks fully opened at least the flame isn't stupidly large and can still be controlled by the lever valve on the manifold and the knob on the torch itself.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 24, 2021, 09:16:07 AM
Well Flamefast came up Trumps :thumbup:   (cards that is not politicians !)

Were I to make a donation to a nominated charity they would pop some bits in a box and send them to me - a refreshing way of doing business ! That was Monday afternoon, today (Wednesday a box arrived containing 5 kgs of rather special 'RCF Mastic', an 18" square of 4 mm pretty solid Kaowool blanket,  Two face masks, two pairs of nitrile gloves AND the proper propane jet  :ddb:

A bit of careful marking out and cutting and the kaowool was reduced to a 12.5" disk with a 7" hole in it ready for use as a thermal barrier between the ceramic tile and the metal plenum chamber.

I then 'caulked' the joint between the plenum chamber and the quadrant tiles with the RCF mastic forcing it as far into the joint as possible as it is this seal that had previously been leaking.

Then fitting the Kaowool disk with the perforated tile on top I caulked all round the tile forcing as much as possible down into the gap. Having got as much in as I could with a putty knife I then forced it further in with a wooden lath cut to size. Another two  trips round the tile with the putty knife pushing the mastic in as far as possible followed by smoothing with a wet trowel and a damp cloth. This seal HAS to be good or the whole rigmarole that I've been through will be a waste of time.

Asking how long to leave the mastic I was told that in the factory they hit it with a gas torch, make it sweat, and then it's ready ! OK I used the forge torch to dry the surface then put the ceramic chips back in and lit the forge, reasoning that hot chips are no different than a darn big gas flame to dry and cure the mastic.

Initially clouds of rather nasty smelling steam then after about 5 minutes things began to clear and the chips started to glow. After ten minutes I'd swear it's hotter over a more even area than i can ever remember it. So with much of the bulk of the ceramic chips glowing white hot I turned it off in the interest of conserving propane  - I'm sure that the mastic will now set nicely.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 24, 2021, 09:23:50 AM
Comparing the 'original' propane jet that was in the forge when I got it to the one sent by Flamefast convinces me that someone has altered the holder from 1/2" BSP to M 12, but what is important is the hole for the gas - how big is it?

My currently installed one is 3.5 mm as that was as close as I could get to a #28 drill. I'd been told recently by Flamefast that the jet should be 3 mm, but NO! This jet actually measures #29 (yes I now have a set of number drills!) or extremely close to 3.5 mm so I'm not going to change anything.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on February 24, 2021, 02:38:18 PM
Another useful peice of kit brought back to life Andrew! There is nothing worse than finding a job you have to do and then saying "this would be easy if only X was working" And now it's Perfick!!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on February 24, 2021, 05:26:27 PM
"May cause cancer by inhalation" - that can only mean it's the GOOD stuff :D
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 30, 2021, 09:59:57 AM
So there was I melting the greenhouse . . . . . .

. . . . . OK let me explain, some years ago we had a greenhouse that was a bit of absolute imported rubbish - it didn't last the first winters storms - and for several years now there have been bits of green anodised aluminium channel section getting in the way and being tripped over in the horticultural area. Time to sort them out (I was told).

Now no point in chucking it out, turn it into ingots and save it for later use. Cut up with the band saw into convenient 'crucible lengths' today was it's appointment with doom. I even welded up an extra ingot mould as there was 3 kgs in the bundle.

All put in the pot, coolant water from the borehole circulating, 110 kva generator purring away . . throw the switch Igor  :bugeye:

Wound it up to 50, then 60 then 75 kw - channel section sinking nicely into the melt - hang on - what's that burning rubber smell ?

Now there had been flames off the channel sections, not unexpected with the dross of years on the surface but this was distinctly burning rubber - what's going on and why are there flames down there among the various driver hoses ?

It turns out that one of the driver cables that is enclosed in 'Brewers Hose' for water to circulate to keep it cool, was resting against the 'air hose' (actually braided hydraulic hose that I'd used for robustness), and there must have been enough electromagnetic coupling from the driver hose to the metallic braiding to heat it up and set the rubber sheath on fire !

Turn off the furnace driver, give the hose a blast from the CO2 extinguisher and the flames subside - move the hoses apart - tentatively tilt / untilt the furnace (which uses this hose for the pneumatic cylinder) - OK still working - turn the furnace driver back on while the crucible is still hot, and pour the ingots (second one looks lousy quality)

. . . the good part of this is that it has only cosmetically marked the Brewers Hose (which is darn expense) - OK the air (hydraulic) hose is toast (literally!) but I have miles of that so it's not an issue.

OK Greenhouse melted, domestic demands satisfied, just need to swage up a new hose !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on March 30, 2021, 10:39:40 AM
Andrew,

I know you are fortunate enough to be able to analyse your metal content! Extrusions are usually pretty pure Al. Did you add any Cu? I find 4to 5% Cu makes a harder more easily machinable alloy!

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 30, 2021, 12:34:54 PM
Matthew it's still in the ingot moulds. I made my judgement on how horribly it poured but as you say extrusions are usually LM2 or similar.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 31, 2021, 06:11:34 AM
Added to today's tasks was of course making good yesterday's damage :bang:

Taking the hose off and duplicating it was easy, as I had the crimp ends and 1/4" hydraulic hose in stock, and I also have the proper 'Parker' crimper. It's a bit of a fiddle to manipulate but good solid kit that gives a nice reliable result.

The second air hose running along side this one had suffered a bit of collateral damage but I judged it safe to use - mainly cosmetic scarring.

Now having put it all back together the obvious question is how to avoid the problem in the future  :scratch: I had left the four Brewers Hose power feed cables unstrapped to give more movement flexibility but it occurred to me that these are basically a transmission line (well a pair of transmission lines) and they avoid radiating by the fields of parallel conductors cancelling out (i'm assuming here that the damage WAS stray energy radiation from these leads inducing large currents in the braid of the air hose) so the first thing that I did was Ty-Wrap them into pairs.

However watching the action of the crucible assembly raising and lowering (it tilts) in the down position the power cables press firmly against the air hose which is less than desirable from many point of view. However stopping this is by no means simple. I need the hoses to emerge at a different angle from the base of the tilting assebly.

If I can source some brass 3/4" BSP cone connections that are at 45 degrees then that might be a possible solution but I reckon that they are probably as rare as hens teeth !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: chipenter on March 31, 2021, 09:59:44 AM
Would two ninety's have enough room to be set at any angle you want .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on March 31, 2021, 11:15:15 AM
Jeff that certainly is a possibility, though the whole structure is becoming rather cumbersome. (Remember that these carry thousands of amps as well as the cooling water)

I'm wondering if I can construct a non conducting (but heat proof) gently curved shelf over the air lines to keep the power cables a fair distance when it comes down.

I also want to conduct an experiment with a bit of the braided air hose held close to the power cables when the furnace is at full tilt to see how far away is 'reasonable' - presumably the inverse square law applies. But that is a two person job to be safe as one needs to keep an eye on the generator / cooling system / furnace driver while the other dangles bits of hose and and measures how hot they get!

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: WeldingRod on April 01, 2021, 10:36:19 PM
Zip tie scraps in place with wood spacers?  If the zip tie melts you know it's too hot ;-)

Sent from my SM-G892A using Tapatalk

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on July 25, 2021, 02:46:53 PM
You may recall the problems that I had with the roof of my foundry - lots of leaks, lots of repair attempts etc, it ground on like a cracked record.


Well today we had an absolute deluge in a short space of time. My rain gauge has recorded 43.4 mm in the last 24 hours but a lot of that happened in about 20 minutes.

Hearing how poor old Graham (Seadog) has suffered with his workshop roof leaking badly I thought I'd better go out and see how the foundry was fairing.

Delighted to say just a minor (tolerable) damp patch in one corner, so it looks like the big issues are solved - fingers crossed)

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on July 26, 2021, 05:47:04 AM
Good news, Andrew. I think that you now can be fairly certain that the foundry is water tight, to all but downpours of biblical proportions, that is  :clap:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: edward on July 26, 2021, 09:47:26 AM
One thing that comes out of these rather excellent threads is that I find out about things I never knew I needed - I've had one of those rain gauges since you mentioned it, alongside my existing 'weather station' on my bedside table.

Now I don't even need to get out of bed to see if it is raining or not :-)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 28, 2022, 12:10:21 PM
We've had a lot of rain recently with winds from odd directions, and I was pleased to find on my 'rounds' that although a little had blown into the foundry the major points of previous water entry were dry. Particularly pleasing that the extensive 'french drain' along the side wall has proved to be effective with no water penetrating at the base as it had previously.

However less pleasing was a fault I now seem to have with the CEIF 'furnace driver'. I start the 110kW diesel generator every couple of weeks or so just to blow the cobwebs out, and occassionally run up the induction furnace it self with a bar in it as a 'load' just to keep capacitors polarised and introduce a bit of warmth to keep the damp at bay.

This time all started OK, I ran it up to 30 kW producing a nice red hot bar in the pot, but rhen odd things started to happen. Various errors displayed and the main breaker tripped out. Power cycling it again it started off OK but then all sorts of fault indications mainly round the input voltage and current monitoring.

Now I can't even get the main breaker to latch 'ON'. There is a tripping device - solenoid sort of thing - and I'm not sure in which sense it is supposed to work. I suspect that it needs power to the beast (where two phases are stepped down to 24v AC to power this device which is in series with the emergancy stop button) and this latches it.

Not easy for fault finding as being 415v and HUGE amps everything is well shrouded. I'll resume fault finding tomorrow and power it from my local (low power 16a) 3 phase supply so at least there will be a 30mA RCD trying to keep me alive as I do it. Obviously I can't run at much of a level with that supply but I did once (by mistake!) run it up to 12 KW  :bugeye:

Never mind - I ran the ceramic chip propane hearth up to glowing white heat to burn off a few cobwebs and at least THAT did work  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on November 29, 2022, 05:16:04 AM
That must be rather frustrating, Andrew. At least you're aware of the problem and didn't come up against it when you wanted to use the beast in anger.

Good luck!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 29, 2022, 06:00:33 AM
Yes Graham, it's a bit of a pain !

This morning I've wired it up with a low power 16a 415v feed for testing. 3 phase comes in to a blooming great manual isolator switch QS1 which is a SOCOMEC 35043025 rated at 250 amps equipped with a 24 volt 'manque de tension' (lack of volts) coil (SOCOMEC 39913024) that should trip it and prevent connection if mains isn't present.

After several attempts to manually latch the isolator I did on one occasion manage it and the system was showing loss of lots of DC supplies despite the PSU's tell tale leds being on.

The 'manque de tension' coil is fed from a transformer (TC3) a fuse in the 415 feed  (FU4) and a fuse (FU5) in the 24volt AC line. The transformer is permanently across two phases before the isolator.

I can hear a 'click' as I remotely apply power which is probably the 'manque de tension' solenoid, but may be the relay K1 pulling is, as very oddly the circuit shows K1 coil in series with the 'manque de tension' coil but both are rated at 24 volts and the series chain is fed from 24v AC  :scratch:

However I can't manage now to latch the isolator - it's possibly a mechanical fault with it but that doesn't tie up with the onset symptoms of yesterday when the furnace was initially working.

Testing suspended due to other commitments  :(

https://www.socomec.com/files/live/sites/systemsite/files/SCP/pdf_catalogue/GB/cat_sidermat_en.pdf
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on November 29, 2022, 06:44:58 AM
Andrew,

As you say, it doesn't make sense to have 2 24volt coils in series. Is the TC3 actually 24volts or there about?

Cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 29, 2022, 07:24:49 AM
Yes it's all very odd Matthew  :scratch:

I measure the transformer output as 26 volts AC. By using the emergency stop button (which is in the chain in question) I can power up / down the 'no volts solenoid' and the relay K1 which has a 500 mSec delay built in and it is apparent that the delay is working.

Quite possible that the circuit has been drawn wrong and that the coils are in parallel, or maybe the coil and contact of K1 are interchanged in the drawing. It wouldn't be the first error I've found in the drawings!

I strongly suspect that I'm going to have to pull the big contactor out and try it on the bench - I really don't waant to as it's far from simple and I suspect that it's a red herring as far as the original fault is concerned.

At least the transformer, fuses and relay K1 are all close together on one panel for fault finding but the 'no volt coil' isn't really accessible without pulling the entire contactor.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 30, 2022, 06:09:07 AM
So nothing for it - pull that huge isolator out for examination !

First ABSOLUTELY ensure no main can be connected. Then it's just a case of unbolting the three phase input lines, three phase busbar output lines, disconnecting the trip coil connections, and removing four M6 bolts securing the beast to the chassis.

OK isolator removed  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 30, 2022, 06:25:53 AM
Now at last I can see where the trip coil is located - round the back !

The trip coil unit clips in with it's two wire threaded though a channel to the front terminals. Pulling it out it is all rather sad - obviously suffered water damage and from it's terminals is open circuit. However scratching about, the actual coil is OK (2K ohms) and the solenoid pulls in nicely from 20v DC (bench supply) so I'm confident that I can clean it up to serviceable condition.

With the trip coil removed I can physically latch the mechanism 'ON' and trip it to 'OFF' by holding the lever that the solenoid presses on in the appropriate position - ah good I (ERRONEOUSLY) think.

When latched 'ON' there is no electrical connection between input and output on any of the three phases, and indeed the 'double break' contact arrangement that I assume should slide to the left to impale the contacts onto a bridge piece hasn't moved. This is VERY odd - I must be missing something here

As far as I can tell the entire plastic assembly that holds the three sets of 'double break' contacts should slide to the left onto the bridge pieces but it doesn't - this has me greatly confused  :scratch:

Time to sit and cogitate I think  :coffee:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on November 30, 2022, 07:50:45 AM
Hi Andrew, very often in this type of breaker there is an interlink mechanism which stops the isolator operating unless the trip mechanism is in place, thus preventing nuisance tripping being cured by merely removing the coil. Is there anything that the trip coil depresses  as it is pushed into position? Does the act of resetting the trip push the solenoid core along and actuate the switch at the same time? Baffling!
phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 30, 2022, 08:28:02 AM
Phil, I've looked for such cunningnesses but not found anything. I reinstalled the trip for precisely this reason, using the external lever to put it in the 'volts present' position (rather than 24v activated' and it's still the same.

I'm off back to the workshop for more experiments now though so watch this space !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on November 30, 2022, 10:32:03 AM
OK a bit more dismantling - the contactor is in pieces all over my bench  :bugeye:

Essentially there is a plate that slides that has three sets of contact pieces on both sides arranged so one way up it gives a 'normally closed' contactor, and in my use the other way up gives a normally 'open contactor'. These contacts on their plate slide impaling themselves on the 'bridge piece' thus making a circuit. There is an over centre spring loaded toggle arrangement keeping them slide to the operating side, but when the no volt coil or the manual lever hits the release they spring apart.

There is a spring loaded 'hook interlock' preventing the slider  returning to the operating position which when the contactor goes to 'reset' should be lifted out of the way. At the moment I cannot see what is supposed to lift this hook, and indeed it isn't lifting.

The toggle has two springs, and the one on the right sits in a die cast cup with guide lugs and travel limiting lugs. The travel limiting lugs have broken off  :bang:

More work to fully understand this device but I'm nearly there.

If I really have to I can either machine from solid, or 3D print and lost wax cast a replacement cup but I will probably work out how I can try the furnace without this contactor before c omitting the time and effort to what might be a lost cause.

Remember - all this started mid melt so the contactor was closed anyway so there may well be more serious problems once this one is over come.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 01, 2022, 05:27:58 AM

This morning I lashed the 'trip coil' back into the circuit as relay K1 needs it's continuity, and made temporary links round where the failed big contactor had been.

I powered it up via the 30mA RCD protected 16 amp three phase supply that normally feeds my guillotine as it's close enough to see & hear what's happening but far enough away for safety.

This was just for testing to see what faults are being displayed - and very sadly it's LOTS  :bang:



Much more head scratching needed - sadly it's possible that this will be the end of this journey, as I have no circuit diagrams of the main microprocessor equipped logic board, nor have I ever seen another one after years of watching.

. . .early days yet, I need to retreat, lick my wounds, and cogitate!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on December 01, 2022, 05:40:48 AM
In general, sudden onset of lots of faults is unlikely, although 1 fault could cause lots of damage.

I'd be looking for a power supply issue.
A missing rail, etc.

Or a loose / faulty connector. Is there any other components /modules near that corroded solenoid?

Otherwise a possible sad end to an epic journey...

-russ

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 01, 2022, 09:04:42 AM
Yes I agree Russ.

Well out I went after lunch armed with circuit (just block diagram sadly) to test voltages and try and locate all the fuses. Poked and prodded before applying power and - guess what - it went ready once I'd given it water flow and pressure and pressed the reset button.

I'd been lead astray earlier by all the lights on for the power supplies and microprocessor on the front panel thinking we were awash with errors - but actually being 'green' they are showing 'OK' - the red ones show errors when on  :bang:



Nothing had measured wrong - all supplies were there - no idea what has changed, and of course this may only be a temporary respite but at least it gives me hope. Obviously the program and basic microprocessor are still able to function.

I pinged the resonant frequency of the crucible, and did a very brief 'heat' (16 amp supply remember)

Having typed this out, I've just been back and repeated the process and amazingly it's still working. Again a very brief 'heat' as 70 amps from a 16 amp supply cable is not good  :bugeye:

Still need to sort the contactor out, but at least this makes it worth doing.

Now faults don't just go away - something is lurking - but at least the fundamental electronics seems OK (ish)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 01, 2022, 11:41:55 AM
So now the priority is to mend or replace the contactor.

Were it not for it's remote tripping facility it seems that there are quite a few just as 'manual isolators' - but the tripping is the only thing that the eStop button acts on and I'd like to retain that !

World wide searches haven't turned up any used ones, and although new compatible ones seem to be available their price rules them out at several hundreds of pounds.

The bit that is broken is a zinc or maybe aluminium based die casting - boxing it up is occupies about 50 x 50 x 65 mm. The hole for the big spring is 40 mm o/d by 36 mm deep.

Options:

A/ Machine one from the solid - time consuming but many of the features are there to minimise material use so wouldn't need to be incorporated.

B/ 3D model it, print in PLA and get it lost PLA cast in bronze.

I'm leaning towards option B - it worked well when I needed that drive dog for the Beaver lathe live tooling. I'm not even sure my copy of Fusion 360 is still operable - not used it for over a year and they have a habit of chucking you out !

As always comments and suggestions would be very much welcomed.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vintageandclassicrepairs on December 01, 2022, 05:18:56 PM
Hi Andrew,
I despaired when I saw the contactor in bits  :(
I wonder if there is moisture getting into the unit? due to the condition of the trip unit?
Does it have an internal heater to prevent condensation? if not I would add one (main fed)
I really hope you are sucessful in getting the furnace going again
If I had access to my old workplace I'm sure something could be found that would work? sadly that's not possible

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on December 02, 2022, 04:35:20 AM
Could you not superglue it back together just to see how it works, my feeling is that the slope on the hook contacts the broken off pieces and is pushed to one side till it passes the "obstruction", and then latches, but it is very difficult to sus it out without having the mechanism in front of you! Could you cast one in aluminium using the repaired original as a pattern? At this scale the shrinkage may not be that important, you could add a few coats of high build paint to thicken it up a bit!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on December 02, 2022, 04:39:59 AM
So now the priority is to mend or replace the contactor.

B/ 3D model it, print in PLA and get it lost PLA cast in bronze.

Lost Pla's the way to go!

Cheers, Matthew
I'm leaning towards option B - it worked well when I needed that drive dog for the Beaver lathe live tooling. I'm not even sure my copy of Fusion 360 is still operable - not used it for over a year and they have a habit of chucking you out !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 02, 2022, 06:17:31 AM
Thanks chaps for your input.

Phil, those broken lugs take the full force of a very strong spring which is why they've broken off - sadly superglue won't be strong enough.

Yes lost PLA is what I'm shooting for.

This morning I steamed up my copy of Fusion360 and it forced me to do an update as I've not used it for a long time, and now it seems I'm on a 30 day limited trial.

Actually remembering how to use it is proving difficult - it's not at all intuative to me.

. . . . Where's Jules when you need a 3D model . . in fact thinking about it, he's not been arround in quite a while - I hope he's OK :scratch:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 02, 2022, 08:51:03 AM
Andrew, if only you had industrial quality cnc machinery and a foundry you could machine a pattern and cast and finish  it yourself.  :poke:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 02, 2022, 10:48:52 AM
Ho Ho Steve - you obviously have a career ahead of you on the stage  :lol:

So mangling my brain this afternoon I've produced an embryonic 3D model using Fusion360 - oh boy my head hurts ! It's printing at 20% fill (ie weak) using PETG as it was in the printer. This will let me see if it fits.

I've omitted the unnecessary features - extra  holes and other material reducing measures that were in the original - hence a model to see if it fits !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: ddmckee54 on December 02, 2022, 03:04:28 PM
Andrew:

If the part fits, you might want to try increasing the infill and print it again.  It might actually work for a while.

Don
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 03, 2022, 05:58:23 AM
So the 3D print finished after 3 hours 21 minutes last night. It's come out well and it fits.

Not only that I was able to latch and unlatch the mechanism - as someone suggested, one of the lugs on the 'spring pot' pushes the hook latch up when reset. It's the upper single bar not one of the ones that broke off.

I was not at all surprised the the PetG print broke when I tripped the mechanism - in fact it broke just like the original !

I've subsequently noticed that the lugs that broke off were not 'merged' with the main body but rather are intimately close to it, so no reinforcement crosses their junction. Fine for lost PLA casting but no use as a component as is.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 03, 2022, 01:08:20 PM
Well you can't win 'em all  :bang:

Printing the PETG at a greater density gives it much more likelihood of warping and pulling away from the build table - I have a heated platen on this 3D printer but I forgot to turn it on.

I could see that it was beginning to curl away from the base but hoped that it would stay stuck to the end - no - it became detached and produced a birds nest.

Never mind - I'll do it again tomorrow with the heater on, but the print that I got here demonstrated dramatically more strength due to the 80% fill density (was 20%)  and the fact I merged the lugs into the main body so that they were one entity with the mesh layout running between them.

I suspect a good PETG print will have the strength to do the job, at least for testing, but it becomes quite weak at higher temperature so no good for the final item - that will be lost wax PLA cast in bronze. So PLA versions to be printed as well tomorrow.


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: djc on December 03, 2022, 01:30:21 PM
I wonder if it is possible to bypass or reduce the spring force on the ears of the die cast bit.

Drill a hole through the casing concentric to the spring and use a sliding, adjustable stop bolt (maybe with a rubber washer on the outside as a cushion.

Would lumiweld or similar repair the original metal part?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 03, 2022, 04:41:27 PM
I don't fancy introducing other bits into the breaker though I see your point.

My first thought had been Lumiweld, and indeed I have some, but decided not to do it at this stage incase it all droops into a puddle and I'd have lost my chance to check dimensions. When I have a working PETG model then I may well try it.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: howsitwork? on December 07, 2022, 02:58:10 AM
Andrew

Having just returned to forum after a while away. I’m fascinated and terrified at the same time !
That’s some serious power you’re playing with but makes interesting reading . Stay safe .

And of course good luck !
Ian
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 07, 2022, 05:55:39 AM
Yes it's all a bit scary Ian - definitely a 'one hand in you pocket' approach to probing needed !

Well there has been major progress on the 3D model of the bust 'spring pot' - I have a model that I'm sure will work when cast in something substantial like bronze.

However there has been another set back - I've found that the 'spring pot was not the only thing that has been damaged - and this time it's not going to be feasible to repair it  :bang:

The plastic moulding of the isolator has broken in two places:  firstly where the tube that slides the contact plate has over travelled, it slides in a groove and one end of the groove has broken away and the main body has cracked below it. Secondly there is a plastic formed collar around the operating spindle that has a stop lug on it that has broken off. The plastic is rather crumbly.

SO - I've come to the conclusion that even if I can have my 3D model 'lost PLA cast' and somehow re-build the plastic body of the contactor it will not be safe - so it has to go  :bugeye:

. . the search is on for a replacement . . 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 07, 2022, 06:08:32 AM
Now really I want a 'through door operated' 250 amp 3 pole 415 volt isolator with a 24 volt AC under volt coil'. Without re-mortgaging these fall into the unobtainium category.

Much more common are ones intended for toggle operation inside a cabinet with 'shunt coil tripping' - and I've ordered and am yet to receive an ABB SACE S3 225 amp isolator that is equipped with a 24 volt AC shunt. It's 'only' rated at 225 amps but then my generator is putting out about 150 amps on full load so I don't think that's an issue.

Now there are 'through door kits' for these breakers and I will certainly keep my eyes open for one but meanwhile just have to open the door to power up. It IS rather dodgy as the cabinet has loads of HV exposed bits - I may have to make up perspex covers.

The 'Shunt Trip' is needed for the Emergency Stop function, and applying 24 volts AC trips the breaker. In the original the 'under voltage coil' works in the opposite sense tripping the breaker if it is NOT powered so I will have to introduce a relay to invert the operation. Again 'under voltage coils' are available for this isolator but I've not found them for under several hundred pound which is a ridiculous price.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 07, 2022, 06:13:05 AM
As I will be re-working the circuit round the eStop I wanted to bottom out that peculiarity whereby the circuit diagram showed the ESTOP relay coil in series with the under voltage trip coil which obviously couldn't be correct as both are 24 volt ac devices powered from a 24 volt AC source.

Some work this morning with bright light and a meter has resulted in me finding the errors on the circuit and correcting it so at least I have a true starting point !
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vtsteam on December 07, 2022, 06:50:18 PM
CNC Mill + touch probe + CAD + block of plastic = replacement plastic part

 :proj:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: mattinker on December 08, 2022, 11:13:03 AM
As I will be re-working the circuit round the eStop I wanted to bottom out that peculiarity whereby the circuit diagram showed the ESTOP relay coil in series with the under voltage trip coil which obviously couldn't be correct as both are 24 volt ac devices powered from a 24 volt AC source.

Some work this morning with bright light and a meter has resulted in me finding the errors on the circuit and correcting it so at least I have a true starting point !

That makes more sense, real 24volt parallel !

cheers, Matthew
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on December 08, 2022, 11:32:05 AM
Matthew it's not the first error I've found in the circuit diagrams for this beast. If the draughtman was given a hand written sketch of the eStop circuit I can fully understand where he went wrong confusing cable 304 and 301 and bringing 307 to the wrong transformer leg !

I've managed to source a pretty inexpensive ABB SACE S3H 250 amp contactor that has a 'through door actuator' but no door hardware or handle or shunt trip but seems the same body size as the ABB SACE S3 225 contactor that I have on order that DOES have the 'shunt trip'. So I am hoping to assemble a 'frankenmonster' from the two ABB S3 breakers and the door gear from the original Socomec breaker.

Mounting is going to be fun, as to avoid cutting another hole in the door the left hand side operated ABB breaker will need mounting a lot further to the right as the original has a right hand side operating handle.

The other issue is that I really want to move the supply to the eStop transformer to the switched side of the isolator which is going to potentially introduce timing issues ensuring that the new shunt trip isn't momentarily powered as the breaker closes.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 06, 2023, 06:53:07 AM
Well at long last I can make some progress with this repair.

EVRI / Hermes have lost BOTH contactors that I bought that were to be amalgamated to form one with a rotary operator and one with a 24 volt AC trip mechanism. The sellers of these used contactors fortunately both had additional items which I got sent by Post Office 24 and UPS - the UPS one arriving this morning.

This has allowed me to assemble a 'composite' having the trip and rotary actuator allowing the original Emergency Stop still to work, and the contactor to be operated 'through the door'. However this means I'm sticking with the original rather odd arrangement meaning that the emergency stop relay coil is powered even with the door isolator switch is off. As I'm generator powering the furnace this isn't too much of an issue as it only runs when the furnace is in use. Were it off the normal mains I'd somehow have to re-work it.

Now as you can see from the pictures the old and new contactors are vastly different in size, layout and termination. I have worked out a scheme where I think I can mount the new one so it's operating bar goes through the original door hole, and by re-wiring using 35 mm 'meter tails' with crimped tubular lugs can get it to fit - a bit of metal work to do for the actual physical mounting.

I've drawn it up in Autocad showing the outline and fixings for old and new putting their operating bars in the same location so I can lay out a 'hopefully' workable layout.

. . other duties call but I will return . . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 06, 2023, 09:40:20 AM
Got a bit of time after lunch to make up a mounting panel from 6 mm polycarbonite sheet.

Dimensions seem about right but can't mount properly due to a local shortage of 3/16 UNC nuts ! - I'll probably make some but time presses being a Friday with cottage guests arriving - need to change into 'mine host' mode !

Ty-Wrapped on as the 2-3/4 x 3/16 bolts are only poked through the holes to locate it - still the square operating bar DOES poke through the hole in the door so it's in the ball park  :clap:

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 07, 2023, 11:41:43 AM
I wasn't over happy using 6 mm poly-carbonate to mount the new contactor - it can flex a bit and can shatter - think door being slammed on the handle mechanism - so I decided to remake the mount in 2 mm zintec steel sheet.

Obviously a job for the CNC plasma cutter - so I drew up the panel in Autocad - ported it to sheet cam - and oops - the PC on my CNC plasma table has died :bang:

Gives very odd power on self test beeps that don't feature in the book of words. So diversion into PC fixing - it's quite embedded physically but I got it out and apart - no obvious problems - re-seated things, blew it out with an airline and it came back to life. Probably moisture - very damp at the moment in the welding shop.

OK steel panel made - this let me tap it 3/16 UNC to mount the new (to me)  ABB SACE S3 contactor despite having no nuts !

Then a bit of hefty re-wiring in extremely stiff 35 mm CSA 'tails', followed by re-wiring the trip circuit to use the normally closed contacts on the trip delay unit. . . but no . . not so fast . . .the blooming normally closed contacts aren't working - more moisture problems i think. Well it turns out the the base Estop relay that the delay unit fixes to has an unused normally closed pair of contacts - heck who wants a delay anyway !

So putting my fingers in my ears I put 415 volt 3 phase from a local 16 amp circuit on it as I've done previously and yes everything seems to work as it should. Hit the red button and the contactor trips, power up and the controller goes ready, allows me to 'ping' the crucible coil and then I did a VERY brief 'heat' remember only on a 16 amp circuit at the moment.

I think the only thing left to do is sort out a through door operating handle for the contactor - I've failed to source a genuine ABB SACE S3 one but may be able to machine a converter for the original Socomec one - but that's for tomorrow - been at it all day and I've had enough.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 08, 2023, 06:48:00 AM
Happily it turns out that adapting the original operating handle from the Socomec contactor to the ABB SACE one proved far easier than I had dared hope :thumbup:

The ABB has a 10 mm square operator bar - the Socomac has a 15 mm square bar, AND the original physical door interlock mechanism (Female slotted arrangement on the door and a nylon unequal rectangle on the contactor) will JUST squeeze into the depth where the new contactor sits allowing not only electrical operation of the trip switch but also mechanical interlocking preventing the door being opened when the switch is 'on')

So by milling part of the 15 mm operating bar down to 10 mm square using a rather flaky clamping set up I was able to re-assemble it all AND it works !

I had envisioned having to create 3D parts and printing them out but hoo-ray not needed and the furnace is now back in commission.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: russ57 on January 09, 2023, 05:59:16 AM
Now just need to remember why you needed it working...
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 21, 2023, 05:05:57 AM
Russ - next job is to cast a bit of bronze into a bar for Pete. to turn into an anti-backlash nut for his mill, however external pipework is frozen at the moment !

I had a bit of luck on eBay where an identical 'delay timer module' to the one that I had to remove from the eStop circuit turned up at a very modest price. It's been rather held up in the post, but  arrived today and it was rather TOO identical in that it's normally closed contacts were open circuit at all times  testing with a Fluke :bang:

However it had obviously been previously only using the 'normally open' contacts in it's former application so the other pair had probably been oxidising gently for the last thirty years. Increasing the wetting voltage to 24 on a lab supply with current limiting almost immediately it started working OK and now is fine. (In my application if this contact is not closed the machine won't connect to mains so any doubt about the contact isn't a safety issue)

These units are not designed to be taken apart otherwise a simple clean with a bit of nice abrasive printer paper between the contacts would have given the same result.

When things are a bit warmer in the foundry I'll fit it!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 21, 2023, 09:35:00 AM
A Fast Foray -into a Freezing Foundry and I've Fitted the replacement time delay.

First a quick picture for the record of how I'd borrowed a spare normally closed contact pair on the host eStop contactor in case things didn't work out, then a simple job of re-routing the wiring in the panel conduit having clipped on the time delay. Testing it works just as expected so thankfully a 'none event'.

I was a bit puzzled why the designer had incorporated this 300 mSec delay but thinking about it it gives the microprocessor 300 mSec to close down the various drivers etc before power is lost so probably sensible.


. . .so no 'guv we was never there . . it's exactly as it was  :lol:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2023, 05:23:48 AM
I decided to re-fit the safety covers that I moulded in fibreglass many years ago to cover up the exposed electrical connections to the pot part of the furnace - I couldn't remember why I'd not put them back - now I realise !

It turns out that when I decided to put heavy cable strap links across the quick disconnect fittings as their snap balls were suffering from the huge currents that they were carrying I fitted the straps in such a way that they foul the cover  :bang: It can be re-worked I think fairly easily but not today - my fingers are falling off having done the little I've already done !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2023, 09:39:24 AM
It turned out that the 'modification' was far less of a problem than I'd feared - merely having to shorten the 70 mm CSA cables by about two inches and having ensured that both lugs on a link were mutually at 90 degrees fix the outer one to the underside of the wide copper strip rather than the top. This way the 12 mm bolts no longer fouled the case nor did the link loops.

Altogether much more satisfactory and certainly safer than it has been. There's enough to keep an eye on when pouring hot metal without also risking inadvertent electrocution !

So it's now as I'd intended to years back. I had the pattern I'd made for the fibreglass cover kicking about for a long time but I suspect that it's been disposed of now.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on January 22, 2023, 10:48:56 AM
Looking good Andrew, its coming together well! I am  a bit ticklish on high volts/current today. I used to think nothing about terminating up to 600V at many hundreds of amps, but it is something I have found as I get older that I double and treble check insulation barriers and seperation.Even installing my new 3 phase service panel made me a little nervous after I have been out of the industry for so many years, and I have a huge 3 phase steam cleaner which I "haven't got round to testing" after rebuilding it!!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 22, 2023, 01:02:54 PM
Thanks Phil for the kind words. I made the cover when I was still in Bromley so that's at least 15 years ago. Trouble is not only is this high (ish - 600 v) voltage but it's about 3 kHz with spikey fast rising edges so it doesn't behave like normal 50 c/s stuff !

Cast your minds back to when the feeder hose / cables were resting too close to the stainless steel braded air hoses, and the coupling induced so much current to set them on fire 1

Post #756 here : https://www.madmodder.net/index.php/topic,13100.msg160605/topicseen.html#msg160605

So my next task is to make something a bit more suitable than the offcut of floor board that I'm currently (sorry for the pun) using !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: hermetic on January 23, 2023, 01:15:31 PM
it's about 3 kHz with spikey fast rising edges so it doesn't behave like normal 50 c/s stuff !
 :zap:

Narsty!!
Phil
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 23, 2023, 01:59:11 PM
Not seen it yet, but a friend (at my prompting) reckons he's found an odd length of cement reinforced downpipe approximatly 4" O/D, and my calculations indicate that if I mount this horizontally on the 'casting body' frame the Brewers Hose cables can rest on it keeping them off the air lines.

All theory at the moment - I did find a bit of 5" i/d 5.5" o/d flue pipe  but it's a bit too large and kinks the pipes.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 26, 2023, 05:51:25 AM
Today was the first opportunity to do a 'full power' test on the new breaker arrangement. Cottage guests were out so I could run the generator, and it was no longer freezing so I could return the bore hole pump to service.

So turning on the bore hole pump I opened the ball valve allowing water the flow through the heat exchanger to be presented with a blast of high pressure water all over the place - more frost damage on the far side of the ball valve so at least 'turn offable' !

OK it needs repairing but press on - the water chiller has a few gallons in the tank of glycol dosed water that it circulates through the furnace, so it can run for a short while without the heat exchanger.

I ran the furnace up to about 60 kW and all went well just heating a bit of 20 mm re-bar to glowing but then stopped before things over heat without the bore hole water,

Digging through pictures that I took installing the plumbing that's sprung a leak it's not the easiest to get at but possible - so that's my next task in the next few days - and perhaps extend my frost trace heating system.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 26, 2023, 02:11:48 PM
Frost prevention measures:

My first thought had been the wrap snti-frost tape round the two umbilical hoses that join the water chiller to the flow and return mainifold to the bore hole.

Now tape isn't particulary convenient on flexible pipe but it can be done.

Then I thought: the return pipe is open at the well end - can I adjust the piping so that opening a ball valve it all flows out. But no, the height of the manifold compared to the heat exchanger prevents this.

My current thought is, if when I make good the frost damage on the flow pipe I incorporate  an air input valve, when cold temperatures threaten I can maybe blow the water from both the flow, return and heat exchanger back down the return pipe (thus overcoming gravity) leaving hopefully minimal water in the system.

Any other suggestions would be very welcome.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 27, 2023, 06:27:49 AM
Today I stripped down the water feed  and return pipes from the Borehole to let me take the panel off the wall in the foundry and investigate what actually has burst.

To my surprise I've found that the actual body of the ball valve has split - it's a dead ball valve  :bugeye:

So having ordered up a replacement I've also decided on a 'frost strategy' for the future. The pipe rises from the ball valve and goes through 90 degrees to a convenient  place on the panel. I will replace the 90 degree 1" BSP elbow with a Tee - and the extra 'way' will be reduced to 1/4" BSP, have a 1/4" Ball Valve followed by a 'Male PCL' air fitting.

This scheme should allow me to 'blow down' water from the pipe work and the side of the heat exchanger that isn't antifreeze filled.

As an extra line of defence I've also ordered decent quality pipe lagging and am off now to hunt for a suitable length of frost stop heat trace cable.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 30, 2023, 06:56:54 AM
Glad to say UPS delivered my B.E.S. plumbing order nice and early so I was able to get on with putting it all back together.

A bit of heat released the Loctite holding the 1" BSP elbow to the various other fittings and having replaced the elbow with a Tee, the ballcock with one without a burst bit, and installed the 1/4" BSP air ball cock and PCL fitting I was able to put it all back on the wall. I took great care to mark the blue MDPE pipes for insertion depth and seat them firmly as both have to go on as an assembly - if I've got it right it wont leak . . time only will tell !

Then I removed the old nylon reinforced umbilical pipes that take the feed from the borehole to the heat exchanger, and the return that goes eventually to the stream via our land drains. I had bought some much more substantial stainless steel wire reinforced rubber 'Neptune' hose quite a long time ago as the nylon was a temporary solution - it had worked OK but wouldn't take kindly to a splash of molten metal. So now was the time to uses it.

All went well and I'm now waiting a few hours for the Loctite 542 to cure before I pressurise and test it.

The split / self fixing 1/2" wall insulation for these pipes has also arrived but the trace heating cable hasn't so I can't wrap up the umbilicals just yet. It's going to be great fun installing the trace heating. I've ordered a single  14 metre length the mains 'start of which will begin at the wall panel, wrap in a spiral round the return pipe, enter the chassis of the chiller wrapping round its internal pipes and exit wrapping around the flow pipe ending back at the panel. Or that's the theory - I can imagine quite a tangle during the wrapping !

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on January 31, 2023, 12:52:06 PM
So I put on my brave trousers this morning and wetted up the system - great relief - no leaks phew !
Amusingly I noticed that the water from the bore hole was warmer initially than that circulating in the (not powered up) furnace body and electronics driver (10C compared to about 6C)

So today I've been routing the trace anti frost wire that turned up this morning - it was every bit of the nightmare that I'd expected. No where could I find a minimum bend radius for it - wrapping round the heat exchanger I'd have liked to pull it much tighter but didn't dare.

Lagging the heat exchanger was the obvious thing to do, and I've masses of rock wool slab left over from quietening the generator, but fixing it was a pain. Initially I thought dabs of hot glue gun glue, but fibres just pulled off the slab. Then I thought ty-wraps - which sort of work but if pulled to a sensible tension just squash it, so it's not as neat as I'd wish.

Tomorrow I'll embark on fitting the split lagging to the pipework (Note the pipes with no trace heating are the furnace side of the heat exchanger so are heavily dosed with glycol antifreeze)


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 01, 2023, 07:06:49 AM
This morning I got the pipe lagging fitted.

The pre-applied sticky stuff on the split lagging is pretty effective but is a menace as you try to guide it into tight spots.

I decided to back it up with ty-wraps as I don't quite trust it not to move over time, especially on bends.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 01, 2023, 09:54:31 AM
Before pushing the chiller unit back against the wall I thought I'd fit a foil jacket around  the heat exchanger for two reasons. Firstly the lagging is far from continuous at the top so the marginally warmed air from the trace heating / anti frost tape will rise and go to waste, and secondly the insulation being rock wool is rather friable and tends to shed fibres.

I used standard 'kitchen foil' which is terrible to wrap round things like this with sharp bits - it tears at the slightest catching. I'm sure normal aluminium foil used to be much thicker - this measures as 10 microns - there must be better stuff available surely.

Anyway hopefully that's the frost damage repairs and anti-frost measures finished at long last.

Having dragged the chassis out and pushed it back a few times I thought it sensible to run it for a while to prove it was all still water tight - yes I'm glad to say. Water was coming from the bore hole at 11 degrees C and it took quite a while for the equipment to rise from the 7 - 8 degree level up to marginally below 11. Potential ground source heat pump I suppose !

Anyway maybe I can now get back to casting . . .
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: ddmckee54 on February 01, 2023, 01:32:55 PM
Andrew:

You've got a nice little box shaped bundle there.  Maybe you should check with an HVAC installer and see if you could get some of the foil backed insulation board that they use.  You could use it to make yourself a nice little removable insulated box to cover the heat exchanger.

Don
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 01, 2023, 02:07:28 PM
Nice idea Don but the rockwool and kitchen foil were 'in stock' ! The four pipe and the bolting to chassis also wouldn't help, but it's now done and I'll see how it performs when we have the next cold snap.

The heat cable thermostat turns on at about 3 - 4 degrees C and with a bit of hysteresis probably goes off at 6 or so.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on February 01, 2023, 02:37:30 PM
 :beer:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: ddmckee54 on February 02, 2023, 10:12:32 AM
Andrew:

I totally agree, with all the protrusions it would be a royal PITA to fabricate.  Something like that might be something to keep in mind though, if after the next cold snap you decide the heat exchanger needs a little less coolth and a little more warmth.

Don
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 02, 2023, 10:46:59 AM
I actually USED it today - first time in months !

It was just a proof of concept sort of thing as I sort out the logistics of pouring from the tilting body single handed. I'd like to be able to pour into a conventional pouring ladle and thence into the mould but that implies pre-heating the ladle which has to be supported in the right place catch the charge from the tllting crucible. At the moment the whole furnace body is raised 9 inches on a dolly for convenience of moving about but that makes looking into the 'pot'  a bit hard.

Plan is to put it in it's final operating position off the dolly and weld up a frame to hold moulds,   ladles etc to sit on the floor infront of it. As it is at the moment the melt is up at chest level and leaves me very much in the danger zone when pouring. Once the melt is safely in a ladle it can be distributed to more than one mould on the floor.

But before then I need to clear a path from the Tractor Shed, via the Stable to the roller shutter door on the foundry so I can lift the furnace body off it's dolly with my forklift truck. There is a Zed purlin above it, and I got a block and tackle out to lift it but bottled out thinking bending the purlin and bringing the roof down probably isn't a good idea!

Still I did turn half a huge lorry piston into an ingot today :ddb: :ddb:

Oldish Video of the furnace body tilting to see what I'm on about



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete W. on February 02, 2023, 11:42:45 AM
Andrew,

Congratulations on the progress you are making.

Have you studied how the centre of gravity moves as you tilt the machine with a full molten load?  The legs look to me as though they don't extend forward far enough.  When you get it finally positioned and off the dolly, shall you rawlbolt the legs to the floor?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 02, 2023, 12:53:13 PM
Thanks Pete for the kind words.

Remember that it's sitting on a slightly wobbly dolly at the moment. I probably won't bolt it down but will be adding significant weight in the form of some flag stones sitting on the base. I may change my mind though when I've used it with a heavier charge  :bugeye:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2023, 07:18:38 AM
So today's task - get the Raydyne furnace body off the wobbly dolly and moved to the final resting place. Splits into several phases:

Phase 1 : clear a path from the tractor shed through the stable and round the corner to the foundry. Miscellaneous junk in  the stable was easy to shift, but on the track to the foundry roller shutter were two boxes of fencing bits that could only go out back through the now cleared stable. The 90 degree bend from stable to foundry track can only JUST be navigated by the fork lift, and then only with the forks fully up to clear the bore hole pump brick enclosure - OK Phase 1 completed.

Phase 2: get fork lift in position over the furnace - avoid putting several tons of forklift on the roller door threshold strip and squashing it flat, and lifting too high and taking out the door mechanism or a purlin - to avoid these obstacles I had to roll the dolly / furnace closer to the door and resort to only using one tine to lift with - not good practice.

Phase 3: (the Egyptian Phase !!) lower furnace onto scaffold pole rollers now that the dolly has been removed - roll, skid and manhandle into position. Got it too close to the wall initially - the pipes rubbed the 'Big Six' wall cladding on the way down  :bugeye: - OK moved

It was surprisingly easy to move - (remember single handed) and is now hopefully in its final resting place.

I'd just finished and was tidying up to receive a phone call from a friend telling me that he now has positively located the 4" asbestos cement downpipe that will let me make a better arrangement to keep those pesky pipe off the airline - so that's good  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on February 03, 2023, 04:56:34 PM
That’s a nice looking unit
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 03, 2023, 05:37:09 PM
Thanks Tom, and the beauty is, it's molten metal at the push of a button. The ingot I cast yesterday was ten minutes from starting up the generator to switching it off again.

OK it was only aluminium and only just over a kilogram but so much less hassle than oil or propane.

I still need to organise the ergonomics of pouring . . but getting there!
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 04, 2023, 07:28:45 AM
I had a sudden brain wave - could I manage to sort out the cable movement when tilting using a 'tool balancer' ?

This would relieve the weight of the pipes / cables (never quite sure to know what to call them as they are both pipes and cables !) and I had a vague recollection that I had one tucked away in the welding shop.

Sure enough there it was slowly corroding away on a damp shelf - oh there are TWO !  Both rated at 4.5 kGs but no idea what sort of weight I'm dealing with. Slipping an old set of bathroom scales under a loop of the cables gave me a 4.9 kg measurement but of course as the cable is raised you take more of the weight. But at least in the right order of magnitude. So worth setting up an experiment.

First a 'high point' from a length of 50 mm box section clamped to the structure of the foundry, then suspend a balancer from it with a big Ty-wrap. No not enough lift. OK double up and try both. Yes we are in the ball park and it looks promising - a bit more lift and a better way of adjusting the suspension.

So the hunt is on for a 15 kg balancer (they seem to be adjustable downwards from their rating) - I can fabricate a suitable suspension bracket and will need a nice soft sling to cradle the pipe and I think we may had a solution.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 06, 2023, 04:55:30 AM
The anti-frost trace heating got a mild test this morning, which I'm glad to say it passed :thumbup:

Air temp was -2C as was the metalwork in the foundry. The exposed handle bit of the ball cock that burst was at +3C and the upper fittings on the heat exchanger were at +5.

OK only a mild frost but so far so good.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on February 06, 2023, 02:56:38 PM
How about a length of decent bungy? I might have some that could be suitable.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 06, 2023, 03:26:27 PM
Pete it might well, thanks for the sugestion.

I've just won a used 9-15 kg adjustable balancer on eBay - if that doesn't work out I'll be in touch  :thumbup:
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 12, 2023, 07:20:54 AM
Just a tiny bit of progress today.

The Munson Ring pipe clamps that I ordered have arrived so I've managed to fit the length of 3" non-inflammable down pipe across the rear chassis member to prevent the high frequency cables coupling with the braiding of the air hoses. Pretty simple except the air pipes had to come off to tap the holes and I cut the pipe too long first time so it rubbed on the air hoses as the furnace was raised. Trimmed an inch off and re-fitted - seems to work OK now :thumbup:

Although the more powerful 'Tool Balancer' has arrived I ran out of  enthusiasm so it's not yet fitted. I need to create a more permanent suspension point for it.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 13, 2023, 06:39:28 AM
This morning I found a suitable offcut of 3"x3" angle iron, drilled a few holes and bolted it to the foundry structure as a support for the 15 kg balancer. A bit crude as it's not triangulated and only held in place by a single M12 bolt but I think it's adequate.

Seems to work OK



Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 21, 2023, 05:50:47 AM
This wasn't meant to happen

Feeling a bit low, so this morning to cheer myself up I'd intended to do a quick melt reducing some scrap aluminium to ingots - all going well, generator purring away, furnace beginning to melt the aluminium (running @ 30 kW) - then I noticed water - heck turn off quick  :bang:

Obviously the coolant water that goes through the coils of the induction furnace was pouring onto the floor from the bottom of the 'furnace body'

Thankfully I've erred on the safety side of things, every thing bonded together electrically, and there were no dramas but it was a bit of a worry.

So, furnace driver shut off, generator stopped, bore hole water pump stopped and I can start to sweep the large volume of water off the floor and to outside. It's circulated at 50 psi so a lot comes out in a short time.

Looking at the case of the furnace body water level in the asbestos cement box has risen to the level of one of the vent holes so it must be an internal failure rather than the outside driver pipe/cables. Internally there are short lengths of flexible pipe insulating and coupling the plumbing - hopefully it's one of those that has failed rather than the embedded coil itself. I'll investigate later when things are a bit drier.

. . so why was I feeling a bit low? Yesterday I very sadly had to put Hugo, one of my dogs to sleep. He had developed a tumour close to his heart and really it was the kindest thing to do. But I feel I've lost much more than just a pet - he was a good friend. Those of you who've been here will know he was very posesive of me, grumbled if anyone else sat on the sofa next to me and was very perceptive of what I was thinknig and doing.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 21, 2023, 06:33:31 AM
Water level subsiding so I took off the back of the box. In the words of Wes (*)

"There's Your Problem Lady!"

One of the 13 mm pipes has come clean off its copper tail - now as you can see in the picture these are retained by plastic hose clamps - years back I found that steel ones got too much magnetic coupling and got too hot!

Need to test that the coil is free flowing and that it wasn't a blockage that caused it to come off.

(* This is a quote from 'Watch Wes Work' on YouTube - he repairs vehicles in a rural part of America and previously was a CNC machine repairer so has a very logical and resourceful approach to fault finding - well worth watching)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: edward on February 21, 2023, 07:06:40 AM
Sorry to hear about Hugo, Andrew. Its a massive kick when a good friend like that passes. My two are the only company I have while working at home all day so I can understand how you feel. Sad times :(

I too am addicted to Wes. He reminds me of you in a way, cool, logical, not phased by repairing things. The only thing that horrifies me is the state of some of the 'vehicles' he works on - a product of salty roads and no state inspection I guess, but that these things share the roads with other people is really quite scary.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete W. on February 21, 2023, 07:47:04 AM
Andrew,

My lovely but shy assistant (LBSA) and I offer our condolances on the passing of Hugo.  I fear I can't remember if he was a 'V' or a 'W' but in either case I can't spell it!

There are five German Shepherd Dogs and at least one 'Heinz57' interred in our back garden.  (And three cats.)  One GSD and the Heinz57 passed before LBSA and I were married but we both mourned the passing in turn of the most recent four GSDs.  Making that final decision is always hard, however well one can rationalise it, it's a life so always an awesome responsibility and always painful.

LBSA has talked herself into walking our neighbours' two dogs twice a day, usually three days a week, sometimes five, because the dogs would otherwise be left alone all day with no stimulation and no exercise.  She very much takes the dogs' side!!
 
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Sea.dog on February 21, 2023, 09:54:09 AM
So sorry to hear about Hugo, Andrew. I remember sitting on the sofa with him...

Re the pipe problem. I'd not be happy with a straight pipe stub and pipe that softens with heat. Surely a barbed end would be preferable?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: ddmckee54 on February 21, 2023, 11:05:40 AM
Re the pipe problem. I'd not be happy with a straight pipe stub and pipe that softens with heat. Surely a barbed end would be preferable?

Or maybe just soldering a ring of copper wire around the existing copper stub?  Something that would give the plastic hose clamps a little more traction against slippage.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Spurry on February 21, 2023, 11:12:06 AM
It seems, at times, that we are much kinder to animals than humans.

On the proper topic, what about say 3 olives spaced out and soldered onto the stub?
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 21, 2023, 12:29:38 PM
Thanks chaps for your kind comments re: Hugo

Possible pipe blockage discounted - coil uncoupled and 'blown through'

Yes I was thinking perhaps an 'olive' or two soldered to the stub of pipe would be effective. I've been trying to find photos (from when I grouted in a replacement crucible) of the 'other end' of the flexible pipes to see if the native stubs on the coil are barbed or not but have drawn a blank. I have a spare coil assembly - I'll dig it out and see what it has.

A quick calculation knowing the system pressure is 50 psi and the pipe about 1/2" gives a 'pushing off' force of just under 10 lbs so not enormous, but as Graham said the pipes warm up.

As the stubs are just into a compression fitting I may just turn up some barbs anyway.

I noticed a few weeks ago that the coolant was far from clear - with a brownish tinge - I cannot remember whether it was tap water (probably) or demineralised water with a good dose of ethylene glycol as an antifreeze. Googling induction furnce coolants there are dire warnings not to use automotive antifreezes which I'd intended to use for it's corrosion inhibiting properties. The brown tinge I think can only be iron salts (*), and the walls of the holding tank have a thin brown slime layer that probably is the same. As far as I can tell the majority of the water passages are copper, a bit of brass in places, and a small amount of cast iron in the housing of the circulating pump. Borax has been suggested but I'm loathe to start making up my own concoctions.

Certainly a major clean out and flushing is called for before melting restarts. And the antifreeze will need replacing.

(* when I noticed the brown tinge I thought it might have been coming from the bore hole water, which IS iron laiden but the plate heat exchanger isolates this from the circulating coolant)
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 21, 2023, 01:27:53 PM
A quick foray into the Tractor Shed reveals that the spare coil has indeed got 'olives' soldered on the ends of its centre tap pipes.

Now this coil is not identical to the one currently fitted but was made by the same manufacturer, so it's probable that this is how the 'other end' is terminated.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 22, 2023, 05:59:17 AM
First job this morning - remove the 15 mm copper stubs that introduce the coolant to the coil assembly and sweat on olives to give better retention (hopefully).

(Slightly delayed by having to re-wire the cleaners hoover cable YET AGAIN - traded for cleaning the loo in the workshop !)

Olives fitted, stubs refitted, pipe re-installed and the back of the furnace body given a good blow out with dry compressed air so that any leaks during testing would be more easily detected.

Fingers in my ears I started the Grundfos circulating pump. Tank level is very low as most coolant had previously ended up on the floor but is high enough to feed the pump. Pressure rose to the set point (50 PSI) and there were no dramas of pipes popping off thankfully. Both magnetic flow sensor 'torpedoes' were in their raised position indicating that both coolant circuit have flow. I left it running for a few minutes and no apparent leaks - tank was frothing due to the low level making the return pipe above the water level.

So I need to let it all thoroughly dry out, flush out and clean the coolant circuits and replace the coolant. I have 50 litres of Mono-Ethylene-Glycol on order and also 50 litres of demineralised water all of which should arrive early next week.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: Pete. on February 23, 2023, 02:31:49 PM
Sorry to hear about Hugo Andrew. You've only the puppy left now?

I hope he's as comfortble with my Rosie as your other two were. They were both lovely characters.

 


Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 23, 2023, 03:57:43 PM
Thanks Pete - yes just Abi left - Hugo is much missed. He'd sit on the sofa pressing his back hard as he could  against me then lean over backwards pushing his snout into my shoulder and neck. Silly but I miss those interactions.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: vintageandclassicrepairs on February 23, 2023, 06:44:27 PM
Hi Andrew,
So Sorry to hear about Hugo
It is so hard to lose a constant companion who always listens but never complains
I still get sad when I come across photos or reminders of our last dog "Dot" 7 years later

John
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 25, 2023, 06:45:10 AM
Thanks John.

The De-mineralised water has arrived for the replacement coolant but not yet the Glycol so I got on with a slight modification.

The furnace body needs compressed air to tilt it and if you find that your compressor has tripped out when the pot is full of molten metal and you can't pour it out it's all a bit embarrassing. So I've added a 'tell tale' pressure gauge in the foundry so at least I know that there's air before I start melting. (My compressor is in a Portakabin remote from the foundry)

As luck would have it my compressor is throwing a hissy fit at the moment and not turning off - yet to investigate - could be compressor not getting up to pressure or the switch unit not turning off - only time will tell !

Anyway I can't pressure up the gauge yet as the Loctite 542 has to cure for a few hours.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 26, 2023, 07:18:18 AM
Today I started drawing off the remaining antifreeze solution from the tank - the replacement mono-ethylene-glycol hopefully will be here tomorrow so I can't put this messy job off any longer!

Theoretically straightforward but in practice a pain. I sucked the majority out using a 'wet and dry' workshop vac with the filter element removed, decanting it into drums but the last 15 litres or so had to wait in the vac until I'd been to the local amenity site and emptied the drums.

(The glycol solution is poisonous so needs proper safe disposal - spillages apparently break down in the air over about ten days which is just as well as when the burst happened a lot went on the floor and outside onto the concrete)

Then came the lovely job of wiping the slimy sludge off the tank walls - be dead easy if it wasn't for the pipes everywhere!

. . . anyway - it's done. I will purge the whole system with 'tap water' followed by demineralised water as the flexible pipes and generator cooling loops will still contain the old coolant, but I daren't do that just yet as we can't be certain of overnight frosts.

. . . more when the glycol arrives.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 26, 2023, 10:57:34 AM
Now here's a conundrum: It's been a bit of a concern where the brown (presumably iron) contamination has got into the glycol cooling loop. There are one or two malleable iron fittings in the circuit so they are a possible source, but the heat exchanger has the 'non glycol' side cooled by bore hole water that definitely IS iron contaminated.

Were there a leak across the heat exchanger this could be another possible source - and now the tank is empty is my chance to do some tests. I reckoned that with the bore hole pump running and putting well water through the heat exchanger and the coolant pump not running gives the maximum pressure differential. Pop a cup under the glycol side of the exchanger and run the bore hole pump flat out. Now the return pipe from the plate exchanger drops vertically into the tank discharging at low level. There was a slight puddle under it from drips, which I dried away and placed a spray paint top under it, running the bore hole for 15 minutes.

The result was about 2 ml of liquid in the paint cap  :bugeye:

Now here is the quandary - is this just glycol solution sitting in the pipework and plate exchanger and randomly dripping, or is it bore hole water that has leaked from cool side to hot side :scratch:

I honestly don't know - I tested the collected sample from the cap on my Brix freezing point refractometer and it gave the same reading as the removed coolant of minus 15 degrees centigrade. So this would suggest that it is just residual coolant sitting in the pipework - but IS IT ?

I think that I will have to do a pressure test with compressed air by doing a bit of plumbing tomorrow before re-filling the system.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 27, 2023, 04:43:14 AM
Text from DHL saying the Glycol will be here after lunch so time to rig up a pressure test on the heat exchanger.

Encouragingly the catch pot had caught quite a lot over night which I think implies that the drips are just coolant on the plates held by capillary attraction and slowly falling lower - or is that wishful thinking !

So, firstly - open up one side of the coolant loop and find something to adapt from the 28 mm / 1" compression fitting to the 1/2" BSP output of my pressure test pump. The 'It'll come in handy box' furnished the needed bits.

Then opening the ball cock on the input side of the heat exchanger I pumped a fair volume of water, hoping to as far as possible force the air out and water in. Then, closing the ball cock I pumped the test pressure up to 200 PSI (system normally runs at 50 PSI) and will leave it for at least an hour to see if it holds, but so far so good.
Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: awemawson on February 27, 2023, 10:36:50 AM
After an hour and three quarters the pressure hadn't altered one jot so I put the plumbing back together and started a 'tap water flush' involving filling the tank from buckets until above the pump input, running for a while, then "aqua-vaccing" it all out. The tank is not the easiest of things to pour a three gallon bucket into. I did three cycles of this purging with tap water until things ran reasonably clear.

As I was finishing the last flush the glycol arrived - perfect timing. I started off putting in 25 litres of de-ionised water and 25 litres of  glycol and measured the freezing point with the refractometer - minus 40 C IIRC. I was aiming for -15 degrees so added a further 25 litres of water giving me -10 as a freezing point. As the level of the coolant was now almost covering the return pipe (want it covered to avoid frothing) I added glycol until the return was well covered, then titrated with demin water until I got my -15 freezing point.

All a lot of fussing about but at least it's now done and any doubts about the integrity of the heat exchanger are dispelled.

I have a cheap Chinese water resistivity meter on order - apparently the coolant needs a bit of conductivity but not too much and I still have room in the tank for a few more litres of fluid if things need tweeking.

Title: Re: Resurrection of a CFEI 100 KVA Induction Furnace
Post by: tom osselton on February 27, 2023, 05:53:05 PM
I’ll get the popcorn!  :beer: