![]() ![]() Petroleum Jelly (Vaseline)-Formula: 1 part petroleum jelly 2 parts kerosene. This separator is one of the most widely used of all parting compounds and is particularly recommended for use with glue molds. If brush marks show, thin mixture with more kerosene or by warming. Apply to pattern with a soft brush, preferably camel’s hair or sable hair. Melt stearic acid by warming: remove from heat source and add kerosene with constant stirring until a uniform mixture is obtained. Stearic Acid and Kerosene (Stearine)-Formula: 1/4 lb. Remove excess soap with a clean wet sponge before pouring mold. SeveralĬoats may be required on a new mold. Apply parting soap with a sponge and work into plaster surface. Parting compound when cut 10 to 1 with distilled water. Soaps-A number of special “potter’s” soaps are available for use as parting compounds. Some of the most common and widely used separators are as follows: Do not react destructively with the plaster or gypsum cement surface, or with the pattern. Spread easily and uniformly in a thin, continuous insoluble film.Ĥ. Prevent adhesion to the gypsum cement plaster cast.Ģ. Separators Satisfactory separation agents must provide the following functions:ġ. Sand the pattern or model and apply several coats of a clear lacquer. After wood filler has set overnight, apply a coat of a clear acrylic sealer and allow to dry. Apply a heavy coat of Hydroperm gypsum plaster and let it dull down then wipe off excess by rubbing across the grain. A paste wood filler can be used to fill the grain of the wood, but should be reduced to a satisfactory brushing consistency with the recommended thinner. Mahogany patterns or models require special treatment because gypsum cement plaster casts may adhere to undercuts caused by multiple pores or grain of the wood. ![]() Apply second coat after first coat has thoroughly dried.Where a plaster or gypsum cement pattern is used, apply lacquer immediately after set. Correct procedure is to reduce lacquer with lacquer thinner so that the model or pattern readily absorbs the first coat. Two coats of lacquer provide more resistance to moisture than shellac. Patterns of metal, glass, plastic and other impervious materials normally do not require sealing.Ī quick-drying lacquer applied by brush or spray gun is an excellent sealer for wood, plaster and gypsum-cement patternsĪnd master models. Gypsum cement plaster patterns also require sealing to prevent them from absorbing water from the plaster mix and causing the mix to adhere to the gypsum cement pattern. Sealing is particularly essential for wood patterns to prevent dampness from causing the wood to swell, resulting in release difficulty. It “sets up.” Porous model materials require sealing prior to application of the parting compound.Īll porous models, patterns and molds must be sealed before the parting agent is applied. ![]() They also permit removal of plaster or gypsum cement from the surface of the pattern or model upon which Parting compounds (also called “separators” or “releasers”) are needed to prevent adhesion of plaster or gypsum cement to For producing permeable plaster molds for precision casting of many nonferrous metals and alloys. HYDROPERM gypsum plaster is a specially formulated product incorporating an air entraining agent to provide permeability. ![]()
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