This ratio of 88% Bismuth and 12% Tin is the best ratio we have come up with as a substitute for lead. This alloy melts at about 395 F and is best cast or poured at about 500F. Testing the hardness with a Lee Hardness Testing Kit, we came up with an average of 19.3 on the Brinnell Hardness Scale, although there was a range during the testing.