update too sorting. Checked some of the light weights with a magnet this morning and they are magnet. I was not aware the some of the weights were 100% steel. specific gravity of steel and zinc are similar, around 7. Lead varies with the amount of tin but is around 11. not sure why the steel feels so much lighter. I am going to order a thermocouple and readout to monitor temperature b4 I start melting to ingots.