Annealing lead

[Daryl]

Taylor and I have ended up with several hundred pounds of wonderfully pure thin sheet lead from the walls of the X-ray rooms of the local hospital.  It is so pure, I have to add 1/4" to 3/8" of 50/50 solder to it so it won't scum before 25 balls are cast.  The tin doesn't harden them to any extent, and sure makes casting easier.  the first few batches of balls I cast from it turned out blue - with lots of incusions.  It would actually be starting a hard scum before even 5 calls could be cast and I cast quickly.  I've not seen that with any other lead I've used since 1972 Temperature didn't make much difference as with the pot barely melted & too cold for casting yet, it would already be blue on the surface.

[The other DWS]

Daryl, I too have seen that blue film develop on top of a pot of melt at relatively lower temps, especially with sheet lead.
 I have always assumed that since sheet lead has so much more surface exposed there was more surface oxides formed and that was what was cooking cooking to the surface.
sheet lead seems to collect more surface junk anyway so, at least for me it requires more fluxing and skimming than other bulkier sources--like the casks.

[Daryl]

I do flux and skim often with it.  It's amazing how much dirt comes to the surface with this stuff - but man, it is ever soft!

[JCKelly]

Slightly off-topic, as you guys are talking about bullets. My interest was using sheet lead to grip my flint. Hammered out a ball (of lead + a little antimony, I supppose) & found the sheet a little hard. Being a metallurgist, tried to find lead data. Sure. Got  Metallurgy of Lead by Hofman, 1918 & boned up on the subject. Any, well most any, metal gets harder when deformed i.e. hammered out to sheet. Reasonably pure lead eventually "anneals", or becomes soft again, given enuff time at room temperature. A little antimony, a common additive to lead whatever, makes it stay hard longer. But if one is impatient, one may simply anneal it in an oven. I would suggest maybe an hour at 400F, 450F better. One might consider cleaning the lead first & then waiting until M'Lady is shopping before popping it into the kitchen oven. Wrapped in a bit of aluminum foil, should not be a hazard (one suspects M'Lady possibly would not agree). Remove from oven & cool however it suits you, doesn't matter (for softening the lead).

Heat treating to harden lead alloy bullets is a different subject.

[Dave Faletti]

Daryl.  I use pure lead and don't have those issues.  Something may be on it that counteracts your flux.  I ended up buying lead and alloy from a supplier.  Cost me the same as scrap was going for at the time, and I know for certain the purity.  Buying 500lbs helped on price.  If you get it for free or nearly free thats worth some extra effort though.

[Daryl]

Don't know, Dave- this lead is dead soft, that's for sure. Even the sheet, about 3/32" thick, has a bluish cast to it from when it was made.  It even turns blue when the entire pot isn't melted yet - and the crust- oxidation, is incredible.  However, as noted, 1/4" of 50/50 solder in a 20 pound pot of the lead allows shiny silver balls to be cast - yet are still as soft or softer as/than any pure lead I've used in the last 38 years.

It also makes a good lead wrap for flints, yet isn't overly heavy due to it's thinness.  It does add kinetic energy to the cock though and is hard on flints in some locks.