Method of producing molds that can be washed away with water and use of

Abstract

Method of producing a mold from a ceramic composition which can be washed-out with water after use thereof in a molding process, the method including forming a ceramic composition by mixing from about 30 to about 80 weight percent of at least one hemihydrate including alpha-calcium sulfate hemihydrate or beta-calcium sulfate hemihydrate, from about 5 to about 45 weight percent of fire clay, and from about 5 to about 25 weight percent of at least one silicate-based filler. About 100 parts by weight of the ceramic composition are mixed under stirring into from about 46 to about 54 parts by weight of water to form a slurry. The slurry is poured into a formation mold suitable for forming the desired mold and the slurry contained in the formation mold is allowed to set and form a set body. The set body is then removed from the formation mold and dried to provide the mold. The mold can be used to provide molded articles of composite materials, low melting point alloys or plastics, so long as these materials can be heated to at least 125.degree. C. and preferably to at least 150.degree. C. it is the heating of the mold to a temperature of at least 125.degree. C. which renders the mold able to be washed-out of an article molded therewith using water. Heating may take place before, during or after the production of the molded article.