Abstract: A method of surface treatment for plaster articles to improve wear and water resistance is disclosed. The method includes the step of forming the article, allowing the article to set, drying to remove excess water, applying a coat of substantially molten Candelilla wax onto an exterior surface of said article, maintaining said wax at a temperature of no less than 155.degree. F. (68.degree. C.) for sufficient period of time to allow said wax to substantially fill exterior pores and irregularities, and cooling said article to solidify the wax. Also disclosed is a wear resistant and water repellent plaster article comprising a formed plaster article having an exterior surface portion thereof coated with a thin layer of Candelilla wax, said coated surface portion providing a substantially water impregnable barrier and providing enhanced wear resistance.

Abstract: A method of surface treatment for plaster articles to improve wear and water resistance is disclosed. The method includes the step of forming the article, allowing the article to set, drying to remove excess water, applying a coat of substantially molten Candelilla wax onto an exterior surface of said article, maintaining said wax at a temperature of no less than 155.degree. F. (68.degree. C.) for sufficient period of time to allow said wax to substantially fill exterior pores and irregularities, and cooling said article to solidify the wax. Also disclosed is a wear resistant and water repellent plaster article comprising a formed plaster article having an exterior surface portion thereof coated with a thin layer of Candelilla wax, said coated surface portion providing a substantially water impregnable barrier and providing enhanced wear resistance.

Abstract: Electrical power, instrument and communication cables constructed with combustible coverings can provide a pathway by which fire might spread. Cable fires within a room or compartment can be arrested by the construction of a properly designed "fire break" placed periodically along a cable run; and cable fire spread between rooms can be arrested by a properly placed "fire stop". Cable runs generally include a cable tray or raceway to contain the cables. An effective fire barrier, e.g., "fire break" or "fire stop" may be constructed in such a cable tray or raceway by filling a portion of the tray or raceway with a gypsum composition comprising gypsum plaster, an inert filler mixture of diatomaceous earth and lightweight expanded aggregate, and very small amounts of glycerin, boric acid and a corrosion inhibitor such as a boron nitride, boron nitrile or mixture of such boron compounds.