Identify some lead

[dbh1956]

FIL has some lead bars with "712" and "75" or maybe ".75%" stamped into them. He says they weigh about 50lbs each are are 0.75% antimony. Could i caste pistol bullets with it as is? or add some COWW? What ratio? Also my brother came up with this odd shaped ingot - it seems pretty hard. Any ideas what it might be?

[AlaskanGuy]

Only way to tell for sure is to smelt it down with a tight control of the temp... See what temp it melts at.... If you have a hardness tester, that will tell you a lot.... Without being able to feel it, touch it... Scratch it...

Another route would be using an element gun and find out exactly what it is.... There is a guy around this forum somewhere that has access to one.... Might wanna search through the lead alloy section.... I cant remember who does it... But he is in there somewhere.

[pworley1]

Melt it in a pot by it's self. If it casts good use it.

[bangerjim]

0.75% Sb is really NOT that much. You need more for hardness.

And definitely Sn for fill-out

It is a SWAG on what you have! Only an X-ray gun will tell all.

Just try casting some up and see how it melts and casts. That is 80% of the tale.

banger

[lwknight]

That broken off oval is probably some hard stuff. If its antimony hardened it also probably has the right amount of tin to mix with the pure lead as is.
I would melt off a small test sample and mix a sample of lead with it to see what happens.
I suggest you do not batch mystery metals because there could be something incompatible like zinc babbit that will mess up the whole lot.
I lost 150 pounds good lead to tractor weights because of a small amount of whoknow metal that I thought was babbit.

[bangerjim]

That broken off oval is probably some hard stuff. If its antimony hardened it also probably has the right amount of tin to mix with the pure lead as is.
I would melt off a small test sample and mix a sample of lead with it to see what happens.
I suggest you do not batch mystery metals because there could be something incompatible like zinc babbit that will mess up the whole lot.
I lost 150 pounds good lead to tractor weights because of a small amount of whoknow metal that I thought was babbit.

Babbitt is very good as long as it is NOT one of the alloys of Zn! Check Rotometals for a good listing of some of the many types of Babbitt out there.

banger

[cali4088]

what everyone else said. Melt it. Another good technique is see how it separates from the mold and how easy it will bend right after hardening. Barely being able to bend a small piece right after casting means a hell of a lot of antimony.

[dbh1956]

Thanks for the advice. I've got some molds and other supplies ordered from Midway. RCBS LAM 2 from evilbay. FIL gave me an RCBS pro-melt. Missing the mold guide so i called RCBS and they're sending them to me no charge. Got to love RCBS.

I was hoping the 712 was Pb, Sn and Sg or something like that. And the .75 was arsenic. I'll cast it up and see what happens!