[TheForge] Getting the lead out or the tar baby?

[Peter Fels & Phoebe Palmer]

Hi Steve;
My guess is that you are not annealing often enough,
or cooling too abruptly, 
or overheating when you do anneal..
Army helmets are designed to resist impact, after all. They are probably fairly high carbon steel for strength,
 but given that they are drawn to shape, should be quite formable once properly annealed.
As for planishing out the irregularities...
i'd recommend a solid steel dome stake of about the right curvature to work against,
and a flat, polished  face planishing hammer.
It will give you a much better surface in less time.
Lead hammers have their place, and this probably isn't it.

Unless they are intended for actual combat, I'd respectfully suggest starting with mild steel.....
Ideally a deep-draw alloy.
Much less work.

On Jul 27, 2013, at 12:22 PM, Steve Bloom wrote:

Greetings --

I wanted to pose a question to the smithing-mega-brain.  I'm building an 8-plate kabuto with a student.  The process involves over-dishing 16-gauge mild steel pieces (8 of them - who would have thunk") and then planishing them onto a form (with lead hammers).  The form are surplus and slightly modified Army helmets (Italian are best - due to the shape but US units will do and are readily available).  Unfortunately. the steel in the helmets wasn't really intended to take repeated blows, so fracturing is just a matter of time.

I decided that a cooler way to do the work would be to thicken the rim (so a vast number of vise-grips can hold the pieces in place) and fill the form with something resilient to extend the life time of the form.  My candidates are lead and roofing tar (both available in my junk pile).  The volume for the form is about 3000 cc.

Lead is about 11.4 times the density of water, so that translates to 75 lbs of lead.  The equivalent in tar is about 6 lbs (and also melts at a lower temp and has less health implications).  Soo....my question is "Will the tar stand up to the punishment or would the lead be better overall?"  It works in pitch bowls but as a form filler?

I would appreciate anyone with repousse and or armour dishing to chime in.

Thanks -- steve

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