What is tempered glass?
Tempered glass is manufactured by putting glass through a process of extreme heating and rapid cooling which makes it harder and four to five times stronger than normal glass.
Tempered glass also breaks in a unique way. If any part of the glass fails, the entire panel shatters at once into small oval-shaped pebbles.
This distinguishes tempered glass from normal glass, which might experience a small crack or localized breakage from an isolated impact. This eliminates the danger of sharp edges and due to this property, along with its strength, tempered glass is often referred to as safety glass.
What other products use tempered glass?
Tempered glass is used in computer screens, skylights, door windows, shower screens, automotive glass and other areas where strength and safety is paramount.
Tempered glass is also used where heat resistance is required such as fireplace doors, windows in ovens and glass carafes in coffee makers.
What are the steps for tempering glass?
Glass is cut into the required shape first. This has to be completed before the glass is tempered, as the tempering process will weaken the glass if it is cut or etched later and can increase the chance of breakage.
The glass is inspected for imperfections as cracks or bubbles may cause the glass to break during the tempering process. If any defects are found then the glass cannot be tempered.
The cut edges are sanded and polished smooth. This removes any burrs created during cutting or etching.
The glass is washed to remove any grains of glass deposited during sanding, as well as any dirt that may interfere with the tempering process.
The cut glass is heated in a tempering oven. Glass is fed into the tempering oven 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 then subjected to high-pressure blasts of air at various angles. This rapid cooling causes the outer surfaces of the glass to cool and contract faster than the center, giving the tempered glass its strength.