To be precise, it is not possible to cut tempered glass. This is a type of glass also called "safety" and every attempt to cut it crumbles into small pieces. Although it is not possible to learn how to cut tempered glass, you can still cut annealed glass. Then you will subject the cut piece to quenching.
Steps
Step 1. Get to know the annealing process
It consists of uniformly heating the tempered glass to remove internal tensions. These stress points are the reason why toughened glass cannot be cut.
Step 2. Annealing begins
In a furnace, you subject the glass to heat that constantly increases until it reaches the annealing viscosity of η = 1013 Poise. The time required depends on the size of the glass.
The Effetre (Moretti), Bullseye and Lauscha glasses should be subjected to a heat of 504 ° C. Borosilicate glasses should reach 566 ° C. Satake tempered glass, on the other hand, should reach 477 ° C. A small glass ball takes 20 minutes, larger balls an hour, and large glass "sheets" up to 12 hours. Pieces of glass that weigh around 45 kg or more take a month to process
Step 3. Slowly cool the glass to below the point of tension (η = 1014, 5 Poise)
It has to be a slow process so that no other stress points develop. For Satake glasses the cooling temperature is 399 ° C, while for all the others it is 427 ° C. The process must take place in the furnace until the glass reaches room temperature.
Step 4. Prepare to cut after putting on safety glasses
Use a straight edge to create your cutting line. Use a glass cutter to engrave along the line, applying medium pressure. Do not pass the cutter blade more than once.
Step 5. Put the 0.6 cm pin directly under the incision and apply firm and sudden pressure to the sides of the incision
The glass will crack along the line sharply.
Step 6. Sand the freshly cut edges with the whetstone, this will make the glass stronger and safer to handle
Step 7. Re-temper the glass if you like
It is a task that should be done by professionals because it is a complex operation.
Advice
- Since the process of cutting tempered glass requires numerous steps, it would be preferable to start with an already annealed piece. Cut the annealed glass first and then let it harden, in this way you save time and money.
- Use a thermostat to keep the temperature inside the furnace constant.
Warnings
- If you try to cut tempered glass it will always crumble quickly. The only exception is the cut made by a professional using a laser.
- When the annealed glass cools, remember that the outside drops in temperature faster than the outside. Just because you perceive a low temperature on the outside does not mean that the heart is ready to be worked. The cooling stresses the glass less and allows a better cut.
