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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