These are manufactured using fully tempered glass as the substrate. There are optical characteristics inherent in tempered mirrors, including roll distortion and the lack of a quality surface for silvering.
Tempered glass mirrors resist breakage and provide a measure of safety from broken glass, but differ in color and reflective quality from standard glass mirrors. Bear Glass uses the highest quality tempered glass mirrors. Modest distortion or heat-generated markings are normal in the tempered glass mirror manufacturing process.
Tempered glass, or toughened glass, is glass that has been heat-treated to make it stronger, more resistant to heat and break in a way to prevent injury.
This has to be done before the glass is tempered, as the tempering process will weaken the glass if it is cut or etched afterward and may increase the likelihood of breakage.
Cracks or bubbles may cause the glass to break during tempering; if any are found, the glass cannot be tempered.
This removes any burrs created during cutting or etching.
This removes any tiny grains of glass deposited during sanding, as well as any dirt that may interfere with the tempering process.
Glass may be fed in batches or continuously. The oven reaches temperatures of over 600 degrees Celsius (1,112 degrees Fahrenheit), with the industry standard being 620 degrees Celsius (1,148 degrees Fahrenheit).
The heated glass is subjected to seconds of high-pressure blasts of air at various angles. The rapid cooling causes the outer surfaces of the glass to cool and contract faster than the center, giving the tempered glass its strength.