Today's wheel weights are not or very little lead. Very hard to work with in small molds. Needs to be cleaned very good before use. So much trash it can mess up your pour pot. Sometimes you can find a guy on ebay that sells pure lead. Pure soft lead is all you want to use until you get more into pouring. Might try local salvage yards also for pure lead. Also check your dentist for the lead they use in their X-rays. Some have it laying around and will give it to you or sell for cheap.
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979