Basic Rules for Hardening Lead

[X-man]

I thought you guys might be interested in the following If you're thinking about experimenting with alloys.

Basic Rules for Hardening Lead-
For every 1% additional tin, Brinell hardness increases 0.3.
For every 1% additional antimony, Brinell hardness increases 0.9.
For a simple equation,

Brinell = 8.60 + ( 0.29 * Tin ) + ( 0.92 * Antimony )​

 

[c.t.smith]

so pure tin is 29 on the brindell scale???? and antimony is 92?????? ERRRRM maybe im missing something

 

[Bassmaster]

If I want my WW lead to get hard, I drop 'em in water

 

[big boar]

CTSmith, methnks you're read that wrong. The equation reads 8.60 + .29 (for tin) = 8.89. If you add .92 for antimony you'd get 9.81. Not bad, thanks for the info. I've heat treated probably a few hundred pounds of bullets and it's like baking a cake. I use a toaster over I got at a garage sale and it's ONLY USED FOR HEAT TREAT. Simple, heat oven to 350 degrees, bake for between 15-45 minutes (depending on desired hardness) remove and drop into water. The reason I prefer this to "dropping" is I get more consistent hardness results. Thanks for the equation.

 

[rallycamaro]

I am assuming you are indicating 1% of each alloy element as compared to the amount of pure lead? E.g. 16 oz. of lead, 1% of either tin or antimony is 0.16 oz., 2% is 0.32 oz., ect. For an 18 BHN bullet I could use 16 oz. lead, 1.12 oz. tin (7%) and 1.28 oz. antimony (8%), giving 8.60+(.29*7% tin)+(.92*8% antimony)=8.60+2.03+7.36=17.99.

 

[jethunter]

Generally speaking the equation is accurate. The trouble is that we seldom know exactly what the composition of our lead is, even when we buy the expensive pre-blended stuff. The best way to determine hardness is to use a hardness tester, and label your ingots accordingly. When you know what you started with it makes it easier to guesstimate what you will end up with.