Definitions
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Avoirdupois: is a weight system, utilized by the United States and England, for measuring commodities except precious metals, precious stones and medicines. The unit weight is the pound and is equivalent to 16 ounces. Button: The round, enlarged end of a casting tree. Casting tree: Main feed line for metal flow in the casting process. CBF finishing machine: A centrifugal barrel finishing machine is a high energy machine. Product is placed in one of several barrels along with finishing media. The barrels spin in one direction and the turret that holds the barrels spins in the opposite direction. Cut-down: First stage in finishing often completed in a vibratory or barrel finisher. DWT (pennyweight): is a unit of troy weight equal to 1/20th of a troy ounce or approximately 1.555 grams. Firescale: An oxide of copper that forms within sterling and gold alloys. It is created and increased by high temperatures for a protracted period of time, particularly in the presence of free oxygen. It appears as a purple stain. Investment: Refractory material composed of silica, plaster and cristobolite. Once mixed with water, the investment is poured into casting flasks that are filled with sprued wax injections. During the casting process, molten metal will be poured into these flasks. Karat: A unit of measure for fine gold, equal to 1/24 part. RTV mold: Stands for "room temperature vulcanization". RTV molds (also known as "cold molds") are made from urethane or silicone liquid that hardens after it has been mixed and poured around the model. The model can then be cut out. RTV molds have a smaller degree of shrinkage than vulcanized molds. Sprues: Channels or feed lines attached to models to allow metal flow. Steam de-wax: Eliminating wax models from plaster casting flasks before placing them in the kiln. Stone in place casting: Casting around stones that have been placed in the wax prior to investing the casting flask. Troy weight: A system of measurement for precious metals and gems where 1 pennyweight (DWT) = 1.555 grams; 20 DWT = 1 ounce or 31.1 grams; 12 ounces = 1 pound or 0.373 kilograms. The name, "Troy," is derived from Troyes, France, the city where the system was first used. Vulcanized mold: Rubber mold made by heating strips of rubber in a metal frame. |