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US 6,355,099 B1Granted
Plaster mixture for forming a machinable composition
AssigneeUnited States Gypsum Company
InventorsSalvatore C. Immordino, Raymond A. Kaligian, II
Life of this patent
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Abstract
A plaster mixture for forming a machinable composition, includes calcium sulfate hemihydrate; an internal lubricating dispersable binder, and an adhesive binder for adhering the plaster mixture to a substrate. In the preferred embodiment, the composition includes calcium sulfate hemihydrate, a poly(ethylene glycol) internal binder, and an ethylene/vinyl acetate copolymer adhesive binder.
Claims26
A plaster mixture for forming a machinable composition, said mixture comprising:
- from about 65% to about 90% by weight of calcium sulfate hemihydrate;
- from about 1% to about 13% by weight of an internal lubricating dispersible binder that disperses when said plaster mixture is mixed with water to form a slurry, is deposited throughout the calcium sulfate dihydrate crystalline structure after set, and allows the hardened composition to hold a sharp corner and a smooth contour when machined;
- and
- from about 1% to about 5% by weight of an adhesive binder for adhering said plaster mixture to a substrate.
1 more element
A method for making a model, comprising:
- preparing a substrate in the approximate shape and smaller than said model;
- preparing a slurry of a plaster mixture and water;
- spraying a first coat of said slurry on said substrate;
- allowing said slurry to harden to form a machinable thickness;
- and
- machining said machinable thickness to the shape of said model.
3 more elements
Dependencies are inferred from the claim text.