CRUCIBLES AND CRUCIBLE BASE BLOCKS
COMPOSITION OF CRUCIBLES
Crucibles are manufactured in two basic compositions: the CLAY GRAPHITE-CERAMIC BONDED, and the SILICON CARBIDE CARBON BONDED. Both types utilize the refractory materials, graphite and silicon, as conductors of heat and for structural strength. Graphite is predominant in the composition of the clay graphite crucible, while silicon carbide predominates in the silicon carbide crucible. Due to its higher heat conductivity and greater strength, the silicon carbide crucible is more popular in industry. The less expensive clay graphite crucible is generally used in the School Shop. Crucible failure in School Shops is generally due to mishandling by inexperienced students, so the benefits of the more expensive silicon carbide crucible would not be realized. Either type crucible can be used for melting aluminum, brass, or grey iron. However, different metals should not be melted in the same crucible. This practice will cause contamination of each melt and it will be very difficult to get good castings. DO NOT use “any size” crucible in your furnace. Use the size for which the furnace was designed.
Crucible size refers to capacity of aluminum. For example, a #16 crucible holds 16 lbs of aluminum. Brass and bronze capacity is three times aluminum capacity ( therefore, a #16 crucible holds 48 lbs of brass or bronze). The crucibles and crucible base blocks listed in our online store are sizes that are regularly kept in stock for immediate delivery. If you do not see the size that you need listed here, please give us a call for a competitive quote.
Please note: our high alumina base blocks are not recommended for brass or bronze. Please order a silicon carbide base block.