There are two basic types of crucibles:
1. Clay graphite-ceramic bonded
2. Silicon carbide carbon bonded
Both types use refractory materials like graphite and silicon as heat conductors and structural elements.
A clay graphite crucible contains a large amount of graphite, while a silicon Fire Assay Crucible contains a large amount of silicon carbide. Silicon carbide crucibles are more prevalent in the industry because of their high heat conductivity and strength. Most of the clay graphite crucibles used in the shop are less expensive.
Unfortunately, students in shops often mishandle silicon carbide crucibles, so the benefits of the more expensive ones would not be realize. Aluminum, brass, and gray iron can all be melt in either type of Gold Melting Crucible. It is not recommend to melt different metals in the same crucible.
Castings will be very difficult to get if this practice is follows because each melt will be contaminate. Your furnace should not be use with “any size” crucibles. Make sure you use the furnace’s designed size.
The size of the crucible determines the capacity of aluminum. An aluminum crucible #16 holds 16 pounds, for example. The capacity of brass and bronze is three times that of aluminum (so a #16 crucible can hold 48 lbs of brass or bronze).
We keep crucibles and Ceramic Ball crucible base blocks in stock for immediate delivery in the sizes listed in our online store. Call us for a competitive quote if you don’t see the size you need here.
Using our high alumina base blocks with brass or bronze is not recommend. Instead, silicon carbide base blocks should be order.