The glass used in oven doors must withstand high heat while simultaneously keeping the temperature inside the oven at a steady temperature and providing a clear view inside. Not all glass is right for the job. Tempered glass has the desirable characteristics thanks to its durability, safety and low conduction.

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   Glass is first prepared for tempering. It is cut into desired size and sandpaper is used to remove sharp edges off the glass. The glass is then washed and sent into a tempering oven, which heats the glass to 620 degree Celsius. Then the glass goes through quenching, a high-pressure cooling procedure. High-pressure air is blasted on the glass, which makes the surfaces cooler than the inside. As a result of this, the outer surfaces go into compression and the inner part remains in tension.