[TheForge] Getting the lead out or the tar baby? - Take 2

Sun Jul 28 01:46:13 EDT 2013

Apologies, i entirely misunderstood.
Sounds like you have been doing it for quite a while.
I remember when the whole SCA was less than  a couple of dozen folks under an oak tree,
during the earliest Renaissance Pleasure Faires.
Allow me to tease your stylistic boundaries please.
For helmet backup.
There are much stiffer, low temperature casting metal alloys than lead...Not cheap though.
There are polymer and fiber rich concrete mixes that are remarkably strong.
There are extremely durable castable plastics, both thermal and multi-part.
Grease up the inside of the helmet and you have a reusable helmet form mold.
Know anyone with a foundry?
How bout taking a flap wheel on a 4 1/2" angle grinder to cut a bowling ball to shape?
The same set up shapes hardwood pretty briskly. 
Hardwood stumps can often be scrounged..That's the path to your  ideal hardwood form.
Less anachronistic  approach would be to use a hammer and chisel followed by a rasp.
I agree with Mike that sinking those shapes into concave forms might be easier though. Stump collection?

Yes, lead hammers sure work and are easy to recast, they are heavy and the blow sticks.
 But using them puts a lot of lead in the air you breathe and messes with fine finishing.
Copper hammer ?

On Jul 27, 2013, at 8:45 PM, Steve Bloom wrote:

At 03:54 PM 7/27/2013, Peter Fels  wrote:
> >>Peter: My guess is that you are not annealing often enough,or cooling too abruptly,or overheating when you do anneal..

I don't mess with heat treat of the helmets - they are designed to resist shrapnel and little else.  They simply are a convenient shape.  Especially when annealed, the desired share will vanish, so that's not an answer..

> >>Peter: i'd recommend a solid steel dome stake of about the right curvature to work against,

which is what the helmets are (but way more fragile).  If I could create hard wood 3D replicas of the helmets, I would be golden -- but I can't.

> >>Peter: 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....

The hammers do work -- as do some of the helms I made 25 years ago still function. And they are intended for SCA heavy combat (effectively impacts from a baseball bat) but we have a misunderstanding here -- the army hats are the forms, the helms will be out of riveted 16-gauge mild steel (thus overlaps are essentially 8-gauge). I just want to extend the life of the forms.

and....At 06:19 PM 7/27/2013, Mike wrote:

>>Mike: Wikipedia says some had way more pieces than that.

Eventually -- the bowl is made of 8-plates overlapping to the rear. The shirokoro (neck guard) are usually 5 arched strips (or many more depending on the lacing) and there is the brow piece not to mention the tehen stack of washers and a really big grommet and a socket for the helm decoration and the mempo (or grill) etc.  But the base step is the generation of 8 plates that mimic the shape of a human head (with some padding - see above)

>Mike: These are for-and-aft strips or radial segments to be riveted together to form the crown of the helmet?  And you're working the 16 ga. cold?

Exactly -- the pieces are symmetrical left-to-right with the frontal and terminal plates being unique -- so the three between are more-or-less sail shaped but repeat -- right/left temple, right/left middle, right/left side-rear though each one is different because a head isn't symmetrical (as I learned making my first great-helm - can you say grill-on-the-nose-and-acres-of-space-around-the-ears - destined for the slack tub).  When done correctly, the margins run radially from the top to the edge (doing a 32-plate unit is WAY more painful).  The plates are over dished in a Yater swage block to create the 3-D bubble, clipped into place over the preceding plates, then planished to mimic the helmet shape in that specific location.  The planishing has to result in the overlap with enough space to set 3/16" rivets (5 rows from edge to tehen)..

>>Mike: I'd hammer a depression in a lead block, then use a combination of:  sinking the 16 ga on the block with a ballpeen or other  round-faced hammer and planishing over a solid iron/steel stake with frequent annealing. Probably that would require some final shaping over other stakes to get the joints aligned.

See above (we're on the same track) but the plates really do not need annealing.  My personal helm went through years of combat without a problem (maybe because I didn't get hit that often back then <smirk>) and the still-in-service ones are a quarter century in service w/o failure.  Heat was never needed and would really complicate the generation of the overlap needed.

>>Mike: For one off, fill the helmet with a mixture of dry plaster of Paris and roofing tar. (Why PofP?  I dunno.  It's what a respectable jewelry/goldsmithing teacher recommended to his students.)  If you're doing a dozen or two, lead.

Right your are (a neuron or so fired up -- I use to know that -- but the ratio??) -- I'll do a search on "pitch bowls + tar + 'Plaster of Paris'.

Thanks for the assist -- eventually I drop pics on my web site.

Steve 
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