Mixing formula using BHN?

[MC One Shot]

Is there a formula to mix lead alloys using only the known BHN but not the alloy mixtures? Thanks

[bumpo628]

I think that if you added equal amounts of two alloys, then the mixture would be close to the middle. There will be some variance depending on the components, but it should be within 10% or so.

[lwknight]

Bumpo, one more post and you get a bullet!!

I think the hardness tends to lean on the higher side of the theoretical average.
It takes almost nothing to make pure lead jump up in hardness and the harder you
want the more increase of percentages it takes because there is a limit.

The rules of thumb only apply to the mid range guesstimates until you approach the point of no return.

[btroj]

Biggest problem with using BHN is you don't know how you got to that BHN.
I can have water dropped wheel weights or air cooled Linotype both measure around 22 but the alloy compositions are vastly different.

BHN is a measure of the physical attributes of a metal, it does not reflect precisely what the alloy composition is.

You are far better guessing what you have and alloying based on that info than using BHN to get there.

[onesonek]

Bumpo, one more post and you get a bullet!!

I think the hardness tends to lean on the higher side of the theoretical average.
It takes almost nothing to make pure lead jump up in hardness and the harder you
want the more increase of percentages it takes because there is a limit.

The rules of thumb only apply to the mid range guesstimates until you approach the point of no return.

That sounds about right,,,err,,normal. Of which is nothing more the hypothetical average of two extremes:?

[waksupi]

I find it easiest to manipulate brinnel hardness by using the toaster oven. 25 degree change can make a difference in finished hardness, from pretty much dead soft, to as hard as you can go.

[sqlbullet]

Short answer is no.

For instance...both old WW and 16:1 have a BHN of about 11. But mixing them with pure lead results in different numbers.