Pottery plaster formulations for the manufacture of plaster molds
AssigneeUnited States Gypsum Company
InventorsAndrzej A. Przybysz, Jeffrey F. Grussing, Salvatore C. Immordino
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Abstract
A plaster composition for making molds for reproduction by casting is disclosed. Calcium sulfate hemihydrate, potassium sulfate and potassium sodium tartrate are mixed together. The potassium sulfate and potassium sodium tartrate are in a ratio of from about 1:1 to about 10:1. Potassium sodium tartrate is present in an amount of from about 1 to about 10 pounds per ton of dry calcium sulfate hemihydrate, and the total of the potassium sulfate and potassium sodium tartrate is from about 2 to about 35 pounds per ton of calcium sulfate hemihydrate. Methods of making and using molds of this composition are also disclosed.
Claims11
A plaster composition for making molds for reproduction by casting having increased water purge rate comprising a fluid mix of a calcium sulfate hemihydrate, water, one of ammonium sulfate or potassium sulfate and one of ammonium L tartrate or potassium sodium tartrate, wherein said one of ammonium sulfate or potassium sulfate and said one of ammonium L tartrate or potassium sodium tartrate are in a ratio of from about 2.5:1 to about 10:1, said one of ammonium L tartrate or potassium sodium tartrate is present in an amount of from about 1 to about 10 pounds per ton of dry calcium sulfate hemihydrate, and the total of said one of ammonium sulfate or potassium sulfate and one of ammonium L tartrate or potassium sodium tartrate is from about 3.5 to about 35 pounds per ton of calcium sulfate hemihydrate.
Dependencies are inferred from the claim text.