Vince 57, I used to make jewelry with the "lost wax technique" first, made a wax model of the design. next, put plaster of paris around it, with a drainage hole. when dry, I'd heat it and pour out the liquid wax. Next I'd fill the mold with liquid silverI'd heated. put this in a centrifudge. Surely if plaster of paris would hold up to liquid silver, it would work for lead. Maybe worth a try? -Karl