A crucible is a heat-resistant container in which materials can be heated to very high temperatures. Our crucibles are capable of holding melted metals such as aluminum, brass, silver and gold.
A crucible is needed to withstand the extreme temperatures encountered in melting metals. The crucible material must have a much higher melting point than that of the metal being melted and it must have good strength even when white hot.
It is possible to use a home made steel crucible to melt metals such as zinc and aluminum, because these metals melt at a temperature well below that of steel. However scaling (flaking) of a steel crucible interior surface is a problem. This scale can contaminate the melt and thin the crucible walls rather quickly. These crucibles can be coated with Marcote-7 to provide some degree of protection between the steel and the metal being melted. Steel crucibles will work if you are just getting started and don't mind dealing with the scaling.
Common refractory materials used in crucible construction are clay-graphite, and carbon bonded silicon-carbide. These materials can withstand the highest temperatures in typical foundry work. Silicon carbide has the added advantage of being a very durable material.
Our Graphite crucibles are rated for 2750 °F (1510 °C). Our crucibles are generally designed for "non-ferrous" work. Non-ferrous means containing no iron. They will handle zinc, aluminum, brass, bronze, silver and gold alloys. You must use Silicon Carbide crucibles when melting silver.