Wheel Weights

[furface]

I melted some wheel weights to day and cast them into a mold. I was picking them up ond one was cracked, I went to bend it and it came apart what do I have ?

Thank You

[patw]

I am new at this, so someone with experience may have a better answer.  Since I have a lot to learn I have been reading about it and remembered reading about bullets breaking. 

 "Antimony (Sb) melts at 1167o F. It is the current metal used to strengthen/harden lead alloys for bullet casters and for numerous applications in the metals industry. It is an extremely brittle metal but has unique characteristics in a lead alloy in addition to its basic hardening, such as the ability to heat treat a lead alloy bringing the final hardness up far more than what the percentage of antimony would suggest. Alloys such as monotype (19% Sb) and stereotype (23% Sb) are so brittle that bullets cast of them can actually break in two by simply chambering a round or dropping it on the floor."
http://www.lasc.us/CastBulletAlloy.htm

[mechanic]

Did you cast them into an ingot mold or bullet mold?  You say one was cracked, how about the others?  Are they the same way?  Not all wheel weights are lead.  Some are zinc or an alloy of same. 

Did you use a bottom pour pot or did you dip from the top?  Sometimes you will have slag on top.  Did you clean and deslag the lead?