Tempered glass is glass that is treated with heat to make it stronger and more resistant to high temperatures, so that when it breaks, it minimizes any injury. It is used for entrance doors, for shower stalls, for screens of fireplaces and stoves and anywhere where solid and safe glass is needed. The process for tempering glass is similar to that used for steel, follow the instructions below.
Steps
Step 1. Cut the glass into the desired shape
You have to do this before you harden it, because if it is engraved or cut after the process, the risk of breakage increases.
Step 2. Check for imperfections
Cracks or bubbles can cause the glass to break during quenching. If you find some of these anomalies, the glass cannot be treated.
Step 3. Sand the edges
In this way, you eliminate any splinters that have formed during cutting or engraving.
Step 4. Wash the glass
You need to remove any grease residue and dust that has settled during grinding. Dirt interferes with hardening.
Step 5. Heat the glass in a quenching oven
You can heat several batches or in a continuous cycle. The oven reaches a temperature above 600 ° C, the industrial ones even 620 ° C.
Step 6. Remove the glass from the oven to cool it down
Overheated glass is subjected to bursts of pressurized air at different angles. The rapid cooling causes the outer surfaces of the glass to contract faster than the center, which is what gives it strength.
Advice
- Properly tempered glass must withstand a pressure of at least 1800 kg / cm2 before breaking but, usually, it can withstand a force of 4320 kg / cm2. When it breaks, it forms small rounded segments. Annealed glass, which is always treated at high temperatures but with a different process, breaks at 1080 kg / cm2 and forms large, serrated fragments.
- The tempered glass withstands temperatures up to 243 ° C without changing its characteristics. A higher temperature weakens it. Exposing the glass to temperatures close to where it was tempered can shatter it.
