chrsgrain
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| posted on 15/4/07 at 07:22 PM |
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more metalwork help needed!
Hi all...
following all your advice after my first attempt at a beaten metal cover, I made a hammerform and managed this...
(click for bigger view)
MUCH better than the first go, the fold in the ali stayed in place and there's much better definition of the curve. Only problem is the split -
and I still needed to make the curve deeper by about 5-6mm. I didn't anneal it (haven't go an oxy set) would that have helped, or is
there any other way of stopping it splitting??
Thanks
Chris
Spoing! - the sound of an irony meter breaking...
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David Jenkins
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| posted on 15/4/07 at 08:04 PM |
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Annealing would probably have prevented the tear - you don't need oxy-acetylene, just a propane torch. Rub a bar of soap on the ali to leave a
streak, then heat the metal until the soap goes black (well, dirty brown anyway). Leave to cool and then it'll be soft again - until it
work-hardens again!
Looks a good effort though.
HTH
David
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907
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| posted on 16/4/07 at 04:32 PM |
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Your getting the hang of this lark Chris. 3rd time lucky?
If you think of how much you need to stretch the metal, probably x2, then the metal will end up 1/2 the thickness.
I agree with David that annealing is a must.
O/A, blowlamp, wok burner on the gas cooker, or even the glowing embers of the BBQ. You'll find a way.
Just a point on the use of soap. A flame may turn it brown without the material getting hot if you heat from the
same side as the soap mark, so mark one side and heat from the other.
Good luck.
Paul G
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John Bonnett
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| posted on 16/4/07 at 05:03 PM |
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Chris, a really good effort, well done. You have achieved a really sharp edge with the good old trusty Hammerform and a very nice shape too. I agree
with what has been said, annealing is really necessary and possibly more than once because the aluminium work hardens quite quickly with that amount
of stretching. For shaping, I cobble up dollies with the radius that suits the job. In this way you can apply an even pressure and achieve an even
bulge without subjecting bits of the ally to more stretching than the rest. The key to it is annealing and you will be amazed how pliable it will be
once you have done the heat treatment. I'm sure your third attempt will be just right.
alb
John
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NS Dev
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| posted on 16/4/07 at 06:03 PM |
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yep, decent blowlamp will do the job. I have now graduated to 19kg cylinders of propane and a Machine mart cheapo torch, cylinders are £18 and the
torch about £20.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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