Lost wax molding comprises coating wax model in plaster, refractory material and fireclay, drying and covering with reinforcing shell

摘要

The process comprises giving the wax model a coating of one or more contact layers based on plaster and a refractory material, and one or more fire clay reinforcing layers, drying the coating and applying a reinforcing shell based on refractory material. After removing the wax by melting the model the mold is baked. The coating contact layers are made from a mixture comprising 40-50% of an alpha -type hard plaster; 50-60% of a refractory material; 0-0.10% of a wetting anti-foam agent; 0.1-0.5% glass fiber; and 0.02-0.20% of a suitable retardant, mixed with 40-50% water. The reinforcing layer is ca. 20% fire clay, preferably with particles of 0.2-1 mm and an optional 0.2-1% glass fiber.