Hello, I’m new to casting lead bullets . But I have purchased molds , a melting pot & a bunch of lead (100 lbs )I either stripped out of an old boat or an elevator .( can’t remember. I’ve had this stuff for 30 years ) . I also have dental lead from X-ray film & rim weights (20 lbs ) . My question is how much if any alloy do I need to add to my melting pot per pound of lead ?