Proper time to check BHN?

[TimBoothe]

Hi all,

Fairly new here. I have been lucky enough to obtain lead in several different batches. I have WW, both clip on and sticky, I have several 15pd blocks and a pile of lead that came from telecommunications cable. I want to take and cast test subject from each of my "lots" so that I can figure out the BHN and then go from there.

My question is, how long should I give the test subject to age harden before I test the BHN?

Thanks a million in advance,
timboothe

[Jbar4Ranch]

If the samples are air cooled, 24 hours is quite sufficient.

[waksupi]

I disagree with that. An air cooled bullet will test out at near pure lead hardness at 24 hours. You will need to let them age at least two weeks, to get an idea of the hardness. On water quenched bullets, 24 hours will give you a pretty accurate reading.

[Jbar4Ranch]

Mea Culpa - I have it backwards, DUH. Tin and antimony are in solution in a molten lead bath. When it is cast, and then allowed to cool slowly, the tin and antimony will precipitate out separately. When the cast bullet is quenched, the antimony and tin are trapped within the lead crystal structure, making it harder.

Back to your reply - An air cooled bullet, of any reasonable lead alloy, will test ~4.8 BHN if tested in less than 24 hours?? Maybe it's something in the lake water up there. Granted, all I've ever used is an LBT tester, but I've never seen results anything like that.