When was tempered glass created

According to Pliny the Elder, ancient Roman historian, Phoenician merchants deserve the credit for the discovery of glass in the region of Syria. The tradition is that a merchant ship laden with nitrum being moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps of nitrum from the ship, which fused and mixed with the sands of the shore, and there flowed sreams of a new translucent liquid, and thus was the origin of glass This story may not be true but Syria was one of the original centers of glassmaking and ancient Phoenician traders sold glass wear all through the Mediterranean countries.

Egypt was another country in which glassmaking was known at an early time. It is believed that the earliest glass object was created around BC in Egypt and Eastern Mesopotamia. The oldest specimens of glass are from Egypt and date back to B. First, the glass is cut to the desired size. To ensure the integrity of the glass, cutting must take place before the tempering process begins. To reduce the chance of breakage during the tempering process, the glass is examined for any imperfections.

Sharp edges are removed with an abrasive, like sandpaper. Then the glass is washed. Quenching cools the outer surfaces of the glass much more quickly than the center. As the center of the glass cools, it tries to pull back from the outer surfaces. As a result, the center remains in tension, and the outer surfaces go into compression, which gives tempered glass its strength. Glass in tension breaks about five times more easily than it does in compression.

Annealed glass will break at 6, pounds per square inch psi. Tempered glass, according to federal specifications, must have a surface compression of 10, psi or more; it generally breaks at approximately 24, psi. Another approach to making tempered glass is chemical tempering, in which various chemicals exchange ions on the surface of the glass in order to create compression.

But because this method costs far more than using tempering ovens and quenching, it is not widely used. Sign up for our email newsletter. 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