Understand that Brinell hardness can vary due to casting temperature, quenching, aging, etc. Assume for a moment all those things are equal (as the economist said).

Assume also that metal purities are certified 99.98% pure from a foundry using only virgin materials.

Assume casting skills equivalent to the finest bullet caster you have ever known.


What is the equation to estimate Brinell hardness given known proportions of lead, antimony, and tin in the relevant range from pure lead to linotype metal ?


Conceivably the equation only has two main effect terms and their interaction -- tin and antimony -- as the lead is assumed to float as the remainder.

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I'm not sure there really is a formual. This is off the LASC caset bullet website.
Common Bullet Alloy Hardness

Alloy BHN
Lead 5
WW (stick on) 6
Tin 7
1 to 40 tin lead 8
1 to 30 tin lead 9
1 to 20 tin lead 10
1 to 10 tin lead 11
WW (clip on) 12
Lead Shot* 13
Lyman # 2 15
Water quenched WW 18
Linotype 18 - 19
Monotype 25 - 27
Oven heat treated WW 30 - 32
Antimony 50

Take a look at this article (by me). It has what you want about halfway down. I have been using it for years and it works pretty well (plus or minus one Bhn). I worked it up testing 185 to 200gr bullets. The actual Bhn will go up with lighter bullets and down with heavier bullets. It also assumes air dropped and cooled. Dropping it into water is completely different.

http://www.sixshootercommunity...bullet_hardness.html

Harry O,

I read your article, very intresting, I learned a lot from it. Maybe you can help me with a question. I have about 170 Lbs of roofing lead, I'm told its about as pure a lead as you can get considering it's scrap. I bought tin and antimony from rotometals to alloy the lead, but I havn't been able to find out how the antimony will alloy in the crucible? Tin and lead melt at low temperature but antimony melts at about 1,166 F. Have you ever added pure antimony into your crucible?

quote:

I read your article, very intresting, I learned a lot from it. Maybe you can help me with a question. I have about 170 Lbs of roofing lead, I'm told its about as pure a lead as you can get considering it's scrap. I bought tin and antimony from rotometals to alloy the lead, but I havn't been able to find out how the antimony will alloy in the crucible? Tin and lead melt at low temperature but antimony melts at about 1,166 F. Have you ever added pure antimony into your crucible?

It will depend on the size of the antimony chunks. If you have big pieces, try to bust them up into pieces as small as you can get. Then buy flux from Bill Ferguson (The metal man). Antimony with the correct flux and correct amount of flux will alloy in at 600* so you also need a thermometer so you don't get too hot.
Add the tin to the lead first as it helps the antimony go into alloy.
Maybe Rotometals has a flux.

Pur anitomny is tought to alloy because of it's higher mleting point. You are better off w/ a antimony/tin or antimony/lead/tin alloy to start w/ & then blend that w/ your lead. Linotype is a great one for this as is monotype, even bag shot will work better than straight antimony. Try Rotometals.com. CHeck w/ the guys on Castboolit forum. There are some addatives you can melt w/ your lead to get the antimony to melt, but again, starting w/ an alloy is easier.