Tempered glass is reported to have been first discovered circa-1902 in France. The Pittsburgh Glass Company (PPG) later developed its own “Herculite” brand of tempered glass and introduced it to the public in 1938. Unlike plate glass, tempered glass when broken transforms into small crystal-like pieces that are much less likely to cut or impale people seriously during an accident. This new form of glass was used in automobile side and rear windows.
The other type of glass for modern automotive use is laminated safety glass that is made up of a piece of clear plastic bonded in the middle to two sheets of glass. This form of glass was first introduced for use in car and truck windshields with the new Model “A” Ford in 1928 and is generally considered to be its first use in the US.
The lead image and the expandable version of it below contains a mid-to-late 1930s Packard sedan and five men carefully placed on two pieces of “Herculite” glass positioned by PPG on wood blocks to demonstrate the strength and flexibility of it’s product before it reaches the breaking point. If you are wondering how the company engineers may have put the Packard on the glass for the promotional photo, the building is equipped with a traveling bridge crane and a hoist, visible at the top left of the photo.
PPG later introduced “Herculite”curved glass for use in automotive side and rear photos.
Tell us what you find of interest in these photographs courtesy of the University of Pittsburgh Library.