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Harold McMaster

Tempered Glass

US Patent No. 3,994,711
Inducted in 2008
Born July 20, 1916 - Died August 25, 2003

Harold McMaster achieved the centuries-old goal of producing high-quality strengthened, or tempered, glass. His invention is indispensable in modern skyscrapers and other applications where glass strength and safety are critical.

McMaster grew up on a tenant farm in northwest Ohio. Inventive at an early age, he built a threshing machine by age ten, and a car motor by 12. To develop his skills, he attended Defiance College on scholarship, and later transferred to Ohio State University where he earned B.A. and M.S. degrees in physics. After graduation in 1939, McMaster was hired as Libby-Owens-Ford Glass Company's first research physicist.

Early in his career, McMaster invented a rear-vision periscope for fighter aircraft and a method of applying electrical coatings to de-ice aircraft windows. In 1948, he founded Permaglass, Inc. where he commercialized glass tempering technology. In McMaster's tempering process, glass is heated and then rapidly cooled, leaving it stronger and able to be shaped. In addition, glass is safer after tempering because it breaks into small chunks with no sharp edges.

McMaster later developed other technologies. In all, he founded four companies and held over 100 patents in the fields of glass bending and tempering, solar energy, and rotary engines.

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