Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace (Read 165263 times)

awemawson · « **Reply #225 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

Never mind, the work of a couple of minutes to cut the weld, grind back and glue it back together the right way

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

AdeV · « **Reply #226 on:** May 02, 2020, 10:32:27 AM »

Quote from: awemawson on May 02, 2020, 05:52:20 AM

...resort to extreme measures welding dogs to the table....

I bet the dogs weren't thrilled about that!

awemawson · « **Reply #227 on:** May 02, 2020, 11:06:31 AM »

We don't take prisoners here Ade

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

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

awemawson · « **Reply #228 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

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 !

awemawson · « **Reply #229 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.

Sea.dog · « **Reply #230 on:** May 04, 2020, 04:14:54 PM »

Tsk, tsk. Poor show Andrew, you didn't repair the damage to the cover

awemawson · « **Reply #231 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 !

russ57 · « **Reply #232 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

awemawson · « **Reply #233 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.

awemawson · « **Reply #234 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

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

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

mattinker · « **Reply #235 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

Sea.dog · « **Reply #236 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.

awemawson · « **Reply #237 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

nrml · « **Reply #238 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.

awemawson · « **Reply #239 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.

mattinker · « **Reply #240 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

hermetic · « **Reply #241 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?

hermetic · « **Reply #242 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

WeldingRod · « **Reply #243 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

RussellT · « **Reply #244 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

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

They also list solders for stainless.

Russell

awemawson · « **Reply #245 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.

awemawson · « **Reply #246 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.

nrml · « **Reply #247 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.

hermetic · « **Reply #248 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

awemawson · « **Reply #249 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!

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Author Topic: Resurrection of a CFEI 100 KVA Induction Furnace (Read 165263 times)