Author Topic: Propane torches for heating sheet metal.  (Read 12368 times)

Offline S. Heslop

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Propane torches for heating sheet metal.
« on: October 16, 2012, 11:57:57 AM »
I've done a few experiments with the weedy torches (and even a weed torch!) I own and haven't had any luck heating a target area of about 3-4 inch in diameter on 1.5mm mild steel to a nice glow for raising, even with it resting on top of firebricks to help insulate the reverse side. I can heat fairly large chunks of metal with decent firebrick insulation, so I figure it's just a matter of the heat dissapating faster than I can put it in.

I've done a bit of searching and in one post bogstandard links a torch on amazon that looks exactly the same as this, sans regulator and hose.
http://www.machinemart.co.uk/shop/product/details/fc108-gas-torch-with-nozzles

All the threads i've found have been for heating lumps rather than sheet though.

Would there be any hope of reasonably heating sheet metal with a cheapish propane torch at all? In the raising videos i've seen they always use oxy acetylene but that may be for the convenience of near instant heating. Oxy acetylene isn't something I could afford myself though.

Offline Fergus OMore

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Re: Propane torches for heating sheet metal.
« Reply #1 on: October 16, 2012, 05:30:18 PM »
Respectfully, I think that you should be giving the forum more information to enable an answer to be useful.

As I see it, no one knows what sort of metal is envisaged or why and when a heat source is required.

I can( or could) panel beat and 'wheel' in mild manganese steel and for that matter, given the right flux stick a tail back on a donkey :drool:
However, heat was not needed for raising until the metal was workhardened or needed  shrinking( which is not raising) :hammer:

Just off the top of my head have you read up Alan Robinson's Repair of Vehicle Bodies?
Alan wrote expressly for beginners at college( and for manure students like me) :dremel:

Offline andyf

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Re: Propane torches for heating sheet metal.
« Reply #2 on: October 16, 2012, 07:33:35 PM »
Not sure exactly what you are trying to accomplish, but I find that some jobs which seem to be losing heat too fast go better if perched on one of the rings of the kitchen gas hob and heated from below while the blowtorch is applied from above.

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #3 on: October 16, 2012, 08:28:11 PM »
Respectfully, I think that you should be giving the forum more information to enable an answer to be useful.

As I see it, no one knows what sort of metal is envisaged or why and when a heat source is required.

I can( or could) panel beat and 'wheel' in mild manganese steel and for that matter, given the right flux stick a tail back on a donkey :drool:
However, heat was not needed for raising until the metal was workhardened or needed  shrinking( which is not raising) :hammer:

Just off the top of my head have you read up Alan Robinson's Repair of Vehicle Bodies?
Alan wrote expressly for beginners at college( and for manure students like me) :dremel:

I did say the metal I was testing on was 1.5mm mild steel sheet. I'd be most likely working with 2mm cold rolled though.

www.youtube.com/watch?v=BpPVf8Z58Xk#t=20s this video is more or less exactly what I want to do. He's raising an 'armet a rondel' style helmet. Might be a bit tough for a beginner but i've been looking for an excuse to try my arm at sheet metal work for a long time. From what i've read hammering 2mm steel sheet is tough work cold and i'd like to reduce shock to my wrists since they're a little tender as it is, but the biggest concern for me is in hopefully reducing noise. My neighbours haven't ever complained about the strange noises I regularly make (bad diet perhaps?) but I don't want to push their generosity.

The only thing i've found for specifically using air mixed propane for heating sheet steel is this article http://www.anvilfire.com/article.php?bodyName=/plans/ething_forge/sheet_metal_forge.htm which seems like a hassle, plus has a pretty large footprint. But maybe it's a pretty blatant hint that a plain old propane torch isn't going to work.

Sorry about the lack of information in the original post though. I'd written alot more at first but I felt it was dancing around the point too much. I might've gotten too aggressive trimming the fat.

Offline Fergus OMore

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Re: Propane torches for heating sheet metal.
« Reply #4 on: October 17, 2012, 03:47:57 AM »
Apologies about the metal  but you are entering into what can only be described as 'blacksmithing' when you mention 2mm mild steel as a possibility.

It's a long- long time since I stood with my father at his anvil but really you need a forge and man size anvil if you are to emulate the world of the armourer
or the smith!

Again, you are going to have to find hammers and tongs and dollies and 'Bob and Aunties' and you will probably have to make them- as they all did.

OK, I was brought up near to a little village called Shotley Bridge where the German swordmakers lived and plied their skills. My father, my two uncles and grandfather were blackmiths and the rest  of earlier relatives made full size steam locos.   

This does not say that with the proper equipment and dedication you cannot finally achieve your aspirations but-- not, I repeat- the way that your present thoughts suggest.

So re-think and re-plan and I bid you well.

Norman

Offline andyf

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Re: Propane torches for heating sheet metal.
« Reply #5 on: October 17, 2012, 04:12:49 AM »
Having seen the video, I appreciate you might consider my suggestion a little impractical, and perhaps likely to cause domestic disharmpny.

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #6 on: October 17, 2012, 11:46:00 AM »
Apologies about the metal  but you are entering into what can only be described as 'blacksmithing' when you mention 2mm mild steel as a possibility.

It's a long- long time since I stood with my father at his anvil but really you need a forge and man size anvil if you are to emulate the world of the armourer
or the smith!

Again, you are going to have to find hammers and tongs and dollies and 'Bob and Aunties' and you will probably have to make them- as they all did.

OK, I was brought up near to a little village called Shotley Bridge where the German swordmakers lived and plied their skills. My father, my two uncles and grandfather were blackmiths and the rest  of earlier relatives made full size steam locos.   

This does not say that with the proper equipment and dedication you cannot finally achieve your aspirations but-- not, I repeat- the way that your present thoughts suggest.

So re-think and re-plan and I bid you well.

Norman

Oddly enough I pass through Shotley Bridge several times a week on the way to Consett.

You're probably right about it being too difficult to get in to, but I don't feel it should be too expensive or difficult setting up with the barebones equipment. From what i've found online most folk into armouring seem to get away with just sticking welded mild steel mushroom stakes or jackhammer chisels into an old stump or even a stout bench vise to form on with reground ball peen hammers, and for tongs I might get away with mole grips and pliers to start with. I feel with alot of these things it's best to start off 'small' and then figure out what could be done better by spending time and money on buying or making proper tools. Rather than the other way round and finding you didn't really need most of the fancy equipment to begin with.

I feel like a real prat asking for advice and then claiming to know better when I dislike the answer, and I appreciate your concern for me wasting my time, but I do get alot of enjoyment from just bumbling around and trying to figure out these crafts, even if it doesn't always work out.

Maybe i'll read more about charcoal forges for heating the steel. Could be quite nice with the winter coming.

Offline Fergus OMore

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Re: Propane torches for heating sheet metal.
« Reply #7 on: October 17, 2012, 12:08:12 PM »
I don't think that expense is really the issue as my sandbag was a leather coat, my apron( not my masonic ones :bow:) was a leather one from Aldi( a welding accessories off) and my dollies and hammers were intially a cheap-Machinemart set with better stuff added. I had a flanging tool etc and a second hand oxy/acetylene set. I got to an age where I was simply too old and gave most away.

Why not try to see if there are any of the old boys still in Consett/Blackhill who were part of Consett Iron Company.

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #8 on: October 17, 2012, 01:23:38 PM »
I've found it difficult really finding anyone else interested in this stuff who's in a situation to help me out. At a certain railway museum I volunteered at a couple of years ago the management wasn't at all happy with me doing anything involving tools or 'obvious' danger for liability and insurance reasons, even though there were alot of really fantastic people there who were more than keen to help me until the boss man appeared. I've also heard that the blacksmith at Beamish museum has had to stop letting just anyone try it out after a couple of accidents. It's a tragic state of affairs but I suppose it's a neccecity since I did manage to saw my foot off i'd be in a situation to sue them.

In the environment i'm currently in there's alot of snobbery towards people interested or involved in the same stuff i'm interested in, so I don't personally know anyone who could stomach helping out. And everyone my grandparents in Consett knew from industry is either dead or they're no longer in contact with.

So i've found that the only thing I can really rely on to educate myself with is unfortunately the internet and my own experimentation, and I've gained a real defeatist attitude towards relying on other people.


Thinking about that anvilfire.com guy's forge, I might try poking my biggest torch through the hole in the bottom of a flowerpot to act as the frustrum, and using a firebrick as the pedestal, and see if it builds up any heat.

Offline PeterE

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Re: Propane torches for heating sheet metal.
« Reply #9 on: October 17, 2012, 03:56:38 PM »
Hello there,

After looking at the video it seems to me that the smith does more or less exactly the same with the helmet as a silver smith would do with a beaker or bowl made from a round sheet of silver.

Many years ago I did precisely that and made a small mug from a circular piece of silver plate. What is done is actually not making a bulge, but moving the material in front of the hammer to form the bowl/helmet. The sides are of a smaller diameter that the plate and the superfluous material then moved forward to create the sides.

If you look carefully you can see that this is what is done. The red hot area seems to get a "wave" of steel in front of the hammer area which is moving material. the trick is to move it evenly to avoid thinning or thickening, and that takes practice.

It is not complicated, but will take time and give you a sore arm in the beginning. The plate must be annealed quite often to avoid hardening and cracking. Some small cracks can actually be fused together by hammering after heating.

My hammer looks as below. As can be seen it is not just a ball pein hammer, it is more lika an ordinary pein hammer but with a bigger end. Mine has two different sizes of peins.



The important thing is to get the plate annealed where work is ongoing and that can be done with a propane burmer. Larger areas of steel would probably require an oxy-acetylene burner due to its higher capacity.

The anvil is a simple curved face like the end of a pipe or a large cylindrical axle. It must be well secured as the banging may well move even large setups.

Well that is my 2 cents.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline Jonny

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Re: Propane torches for heating sheet metal.
« Reply #10 on: October 17, 2012, 05:24:53 PM »
Agree with Fergus even though the video shows using oxy acetylene for convenience.

Decent anvils will be costly though.

If you can weld easy on, make your own forge it only needs to be small.
The only materials needed are scraps, fire brick, fire cement which wont last long and smokeless coal, coke or similar.
If no compressor make it bellows from leather. Now bare in mind if old you have to get the thing lit, can take some doing even when used to it daily for years on end. You would also need to keep the forge going with a few pumps every couple of mins or it will go out.
An extractor wouldnt go amiss either.

Other than that lash out for oxy acetylene mightbe far better if spending short amounts of time.

A forge can take 5 mins to 25 mins to get properley up and running, its hard work if unfit and new coal.
Not a blacksmith we did precision comparitive stuff and worked up to 1 1/4" square bar but mainly 1/2" accurately filed up before heating and annealing.

Smaller parts you could heat job up over the coal with propane, saves lighting the forge.

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #11 on: October 17, 2012, 07:27:45 PM »
Thanks for the advice. I had a rummage through the garage and found some stuff that might get me started. Alot of it might not be ideal but I guess there's no real harm in trying it out. It's far too late to start banging away though so i'll have to wait till tomorrow.

I know all too well about starting and maintaining coal and charcoal fires though. Especially after a recent adventure in trying to cook pizzas in a kettle BBQ (it was such a hassle keeping the coals going that I don't think i'd do it again in a hurry, but the pizzas did turn out pretty good).

Offline Fergus OMore

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Re: Propane torches for heating sheet metal.
« Reply #12 on: October 18, 2012, 03:17:18 AM »
I've tried to carefully read all this and to add what remains of a memory. Dammit, I'm 82+.

You live in Rowlands Gill which in case no one else knows was a mining village bounded on one side by a coke works which made fuel for both domestic and industrial use. The other side has both what was a huge Steel smelting facility and on another where oils were cracked and coal mining took place whilst on the other side- the Queen Mother and 'Alice in Wonderland' lived.
Closer in history is still at least two men in your small village who build and one designs model steam locomotives and I suspect that there is a decent miniature railway, still in the village.
I even got as far on Monday night to find that the once local policeman still visits the area. He,would you believe , used to waste an hour or so watching the blacksmith farrier working at the anvil at Emma Colliery. The information is there but it is a question of being able to adapt it to your needs.
Digressing further afield- but not that far, the local farrier still plies his trade going around stables. He uses the same basic tools as you could use and the whole lot will probably go in a little van complete with a portable forge!

The important thing to mention is that you have to go to people and not wait them coming to you. OK, I'm an exception, I get invitations to go to- well, China and HongKong- and universities and things.

The only thing that I didn't get an invitation was to what was the local grammar school in your village called Hookergate. I wasn't clever enough- or so they said.

Somehow you should avoid the odd chance of information in writing from people on the net- who may or may not know what they are doing.

Again, I am going to get some stick for being rude but recall that an armourer in my day in the RAF went on a course that lasted all of 22 weeks whilst I retired after making my pile at 55 and did a City and Guilds which cost a fortune and lasted-- a mere 4 years!

Hands on, I'm afraid. One day you may see those hands. They are not a pretty sight. The left one still has signs of a huge skin graft. Experience is not cheap!

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #13 on: October 18, 2012, 07:14:29 AM »
Don't worry about coming accross as rude. I appreciate the advice.

Yeah the internet can be a fantastic resource but you really do have to be careful with what you believe. Although one thing I really appreciate about the whole hobby engineering world online (and perhaps why I find the stuff so appealing) is that people are very open and matter-of-fact about what they do and how they do it. It's a nightmare trying to find any decent information on stuff that starts approaching art, such as soft glass blowing or fine luthiering, where everyone's either trying to look like a noble craftsman or sell you something.

I do know of a few people who're into stuff but I just wouldn't feel right approaching them with so little to really give in return though.

Offline Jonny

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Re: Propane torches for heating sheet metal.
« Reply #14 on: October 18, 2012, 09:47:40 AM »
I think your best bet then is to look around for one of those portable or small oxy acetylene torches with bottles. Instant heat when you want it.

Propane will generate way above needed but as you say its cooling off too quick by the cooler unheated areas.

Best way to learn anything is dont read books within reason, go in at the deep end. You will learn a lot more and it will sink in.


Offline micktoon

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Re: Propane torches for heating sheet metal.
« Reply #15 on: October 19, 2012, 04:26:04 PM »
 Hi there , although you have not said exactly what type of helmet you would like to make and I know these helmets will not be the same type. I thought I would post these photos of Roman replica helmets a good friend of mine has made some years ago. Mainly as way of encouagement and to show that a man in a shed can come up with top quality goods with very little room and tools. The helmets were made in Seaton Delaval ( beside Newcastle upon Tyne, for those out the area) in a small coal house type back shed with hand tools , many of which have been hand made / adapted from bits of metal from the scrapyard, an electric drill , grinder and a normal bullfinch type propane torch. Brian who is now 78 is self taught , he learnt by books and the hard way of trial and error in the days before the internet and Youtube. Really going by the principles of 'where there is a will , there is a way' and 'necessity is the mother of invention'. So if you want to do it enough , it can be done  :thumbup:

 This helmet is a replica of a helmet found in Germany, its made from a spun steel bowl  about 1.2mm thick, then the , Cheek pieces , neck guard , ear guards , brow peak etc are all hand cut out, formed, beaten and shaped, using just hand tools a grinder , propane torch , punches etc. All the decoration is hand formed including the rosettes some of which are silver , the rest of the edging and decoration is brass, again hand beaten out and done with punches in repousse manner ( working from both back and front of sheet ), The decorated brass patterned band above the face opening is 7 thou thick brass shim sheet, this is worked with hand tools , like a leatherworker would use, like pens with ball bearings attached to the ends, the pattern is pushed out from the rear and then background kept flat from the front. Most parts are then riveted with handmade brass and steel rivets, some coutersunk and filed flat so hidden and some proud, then the helmet is lined with leather. The cheveron pattern on the peak is brass and copper as per the original. ..................... What can you say except  :med: :drool: :med: :drool: :med: :drool: :med: :drool:



If you thought that was good feast your eyes on this one  :bugeye:

This helmet is a replica of one found in Scotland. A Roman cavalry type B parade helmet, this is all made from flat brass sheet I think, 1.6mm thick, the face mask part which includes the ears is all formed from one flat sheet , it needs to be annealed many times but is only actually hammered / punched when cold unlike steel, its annealed again once it work hardens from hammering/punching, the mask is then silver plated as was the Roman original. The face mask bit has a forehead and the embossed hair part is attached to this after the plating. The helmet is full size and can be worn , the face mask is hinged with a leather strap at the top in the centre and the leather lace secures this around the back or the helmet. I think this one is now along side the original in the museum at Newstead Scotland.



This is detail of the rear of the scull cap part , the cap is formed to shape , more by blocking than raising , that is to say its beaten into a hollow form or sandbag , once the right shape the figures are embossed in using various pundhes and hammers, again annealing when needed, the 3D type embossing is worked from both outside and inside , to work from the outside the helmet is filled with pitch and let to set to support the metal from behind, then hammered / punched from outside inwards ,the same would be done when working from the inside by filling a vessel with pitch and resting the helmet into it until it set then working that area from the inside outwards, Again what can you say except  :med: :drool: :med: :drool: :med: :drool: :med: :drool:



      Don't forget this is all done by a self taught man in his shed with very limited tools , space and only photos and pictures to go on, just the stubborn determined attitude that, 'it will be done', has made it happen :thumbup: . I have seen both these helmets in the flesh and the photos really do not do them justice , they are scanned photos as taken before digital cameras etc. 
    Brian is very modest about his work and as you say matter of fact ............. 'anyone could do it really', 'if they put their mind to it' type of attitude.
  Cheers Mick  :beer:

Offline doubleboost

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Re: Propane torches for heating sheet metal.
« Reply #16 on: October 19, 2012, 04:42:27 PM »
That is amazing work Mick :bow: :bow: :bow:
I remember you telling me about them :doh: :doh:
I had no idea they were to that stsndard  :bugeye: :bugeye: :bugeye: :bugeye:
John

Offline micktoon

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Re: Propane torches for heating sheet metal.
« Reply #17 on: October 19, 2012, 05:03:10 PM »
Oh yes John , as you know us Geordies like to turn out a decent job  :lol:  , all you can say for Brians work is  :bow: :bow: :bow: :bow:

 cheers Mick.

Offline Stilldrillin

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Re: Propane torches for heating sheet metal.
« Reply #18 on: October 19, 2012, 06:00:05 PM »
Fabulous, painstaking work. By a true Craftsman...   :bow: :bow:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline S. Heslop

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Re: Propane torches for heating sheet metal.
« Reply #19 on: October 21, 2012, 07:11:08 PM »
Those helmets are fantastic, and it's nice to know there's people practically on the doorstep who're into the stuff.

Thanks again for all your help though. I'll try make a thread or something about it if I manage to get anywhere.

Offline Fergus OMore

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Re: Propane torches for heating sheet metal.
« Reply #20 on: October 24, 2012, 07:06:51 AM »
Meantime, there is an Edwards Wheeling Machine on eBay for only 2+K.

Nice toy for the big lads. Used one to do up  the old Morris Minor bits.

S'only money. Got duff breadmaking motors wacked :hammer: