#3 4KG Foundry Clay Graphite Crucibles Cup Furnace Torch Melting Casting Clay Graphite Foundry Crucible, #3- 4kg to 6kg depending on the Metal Designed for Melting Gold, Silver, Copper, Brass, Aluminum and More! Torch Application - Designed to use with Fuel/Gas and Medium/ High Heat Induction Furnaces and Kilns Preheat at 400 Degrees for one hour before using.