Subject: Volumetric sheet metal work

From: [email-masked]
Date: Sun, 27 Feb 94 01:24:55 -0500

Does anyone have any experience with sinking/raising sheet metal into
deep volume forms?  I am looking at a project using 12-10 gauge HR to
form a single piece helm.  I would like to avoid using a torch to heat
small area at time for working.  What I would like to do is heat the whole
sheet somehow and apply a ram or press to give me the basic depth before
taking it to the stakes for raising.  Any suggestions or literature?

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From: Bill Hubbard <[email-masked]>
Date: Mon, 28 Feb 1994 16:23:50 GMT

I am also interested in a project of this type.  If anyone does have any
information please could they email me as well as ([email-masked])
or post it to this thread.
Thanks.
I was wondering if you could use successively deeper concrete (ie easy to
make) formers to just pound the sheet metal into shape, with annealling
between stages.  I understand it would stretch thinner at the points of
most stress and wondered if you could get away with using successively
*sharper* curves to get the right shape.  Would this approach be worth
trying? 
Incidentally, various museum and armour experts have assured me that in
the fifteenth/sixteenth centuries, armour was beaten out and drawn up
cold and annealed between stages.  Evidence for this comes from
illustrations of the time.  Too skillfull for me.
Thanks for any advice.
Bill Hubbard
[email-masked]

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From: [email-masked]
Date: Tue, 1 Mar 94 00:57:55 -0500

Thanks for the response.  However, it was blank except for the header.
could you send again?  Much appreciated.  Ben in palm Springs ca

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From: [email-masked]
Date: Wed, 2 Mar 94 21:11:55 -0500

Thankyou for passing along those notes.  I will let you know how it works out.
. Incidentally, I have some experience in making armours.  Particularly in
restoration of 17C pieces, but I will always be learning.  One thing I have
found is that the style of manufacture various from place to place and across
the time line.  It's a wonderful hobby!
PS. If you see any literature related please pass me the title, publisher,
FTP or what ever.
 
Many thanks from the Yank.  Ben

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From: [email-masked] (Rick Cavasin)
Date: 3 Mar 1994 14:16:31 GMT

I've found two methods of dishing that work well:

1) Soft Hammer/ Hard Form - Get yourself one of the large (~4lb) hammers
   with the steel head and rawhide plugs.  Then take a discarded Oxygen/Acetelyne
   tank, cut the bottom off.  The bottom is dimpled in (like the bottom of
   a champagne bottle), and a tank that's about 10" diameter has a dimple that
   is just the right curvature for a helmet.  Clean it up with a sanding disk
   on an angle grinder.  Take your rawhide mallet, and beat into it for a while
   to round one face of it a bit (can moisten the rawhide to speed things up).
   Then just dish the steel in this form.  The rounded and somewhat soft rawhide
   face makes fairly smooth 'dents' in the steel that need minimal planishing.
   Of course, you can't get really deep dishing, and you don't have the 
   flexibility that you get with raising, but it works.  I've done this with
   14g cold roll with no annealing (for plates in spangen helms, knee cops,
   and skull plates in Pembridge style barrel helms).  Not sure how well it
   will work for heavier steels or one piece helms.  With a 4 lb hammer, you
   need to get a rhythm going that recovers the hammer on the bounce, otherwise
   your arm tires in short order.  Different diameter oxygen bottles give
   different size/depth forms.  The tanks have a fixed life as tanks, after
   which they must be cut and discarded.  It's tough to make the suppliers
   understand that you don't want the thing for illegal refilling, so just
   ask for one that's already been cut.

2) Hard Hammer/ Soft Form - Take a big ballpeen, and grind the flat face round
   (if you can find a hammer better suited to the job, even better).  Find a 
   hardwood stump, and bash a depression in the center with the hammer (it 
   doesn't have to be deep).  You now have a hammer and form.

The impression I get is that raising was the prefered method in the middle
ages.  It takes a fair amount of skill (I can't do it yet), but I would bet
that it allows you greater flexibility (and you certainly need to do it anyway
if you're going to do any really deep curvatures).

Hope this helps,
Rick C.

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From: [email-masked] (RICHARD ALLAN JOHNSON)
Date: Fri, 4 Mar 1994 18:32:09 GMT

In article <[email-masked]> [email-masked] writes:
>From: [email-masked]
>Subject: Re: Volumetric sheet metal work
>Date: Wed, 2 Mar 94 21:11:55 -0500

	Along these same armor making lines I have seen VERY smooth knee 
cops and helmets made by using a shotput welded to a bar.
	If my understanding is correct there is a depression in the stump 
that closely matches the shotput (this can be done by chiseling a depression 
and then bashing the shotput into it to smooth it up).  The piece of metal 
is placed on the stump and the shotput is dropped onto it much like what 
churning butter look like.  I haven't tried this personally but the man whos 
armor I inspected used this method on his knee cops and all the lames and 
also his helmet which was a modified bascinet.
	This should be fairly economical as I can get a 12 (I believe) pound 
shotput here for 25 dollars.
	Incidentally does anyone know if it would be possibe to use a cement 
form and a bowling ball for the same purpose.  It seems to me that you 
should just be able to pour the cement and set the bowling ball in it and 
have a very close form in a week or two.  Obviously you would have to use 
leather or something to avoid overly scaring the metal.

	Rick

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From: [email-masked]
Date: Sat, 5 Mar 94 16:06:48 -0500

>also his helmet which was a modified bascinet.
 
I use a heavy rawhide hammer or mirror finished hand drill to work the
metal in a depression.  The depression can be wooden form such as a bowl
hollowed out of a hardwood stump or the bottom of a large oxygen bottle.
   Planishing can be done from the inside or outside depending upon your
preference for appearences.