The annealing process will uniformly heat up the tempered glass so that all the stresses from the tempering process will be removed. These stress points are the reason that tempered glass shatters into countless small pieces when cut. Without these stress points, annealed glass can be cut without shattering.
If you don’t have a flat, heat-proof vessel, ask the art studio manager if they have one you can use. If you’re not in an art studio, speak to whoever oversees or owns the kiln you’re using. You can also purchase such a vessel at an art store or a glass store.
Soak Effetre (Moretti), Bullseye, and Lauscha glasses at 940 °F (504 °C). Soak Borosilicate glass at 1,050 °F (566 °C). Satake tempered glass is best soaked at 890 °F (477 °C). Use the built-in temperature controller to keep the temperature inside the kiln constant. Soak glass beads smaller than 1 inch (2. 5 cm) for 20 minutes to anneal them. This will undo the tempering. If you want to anneal beads larger than this, soak them for 8 hours. [1] X Research source If you’re annealing a large paperweight, soak it for up to 12 hours. Very large pieces of glass weighing 100 pounds (45 kg) or more can take months to anneal.
Cooling the glass too quickly will cause additional stresses to develop and weaken the annealed glass. The strain point is the temperature at which the internal pressure within a sheet of glass decreases. Once the glass has cooled below its strain point, it’s stable and won’t break.
As the newly annealed glass cools in the kiln, the outside will cool faster than the inside. Just because the outside feels cool does not mean the inside is ready. Cooling the glass slowly allows less stress to build up and will result in a better cut.
You can purchase window cleaner at any hardware store or supermarket.
If you don’t already have safety glasses or gloves, purchase them at a nearby hardware store.
Purchase a straight edge at a hardware store.
Purchase a glass cutter at any large hardware store or home-improvement store. Do not run the glass cutter along the line more than once.
You can purchase a dowel at your local hardware store or home-improvement store.
Do not place your hand directly on top of the dowel when pressing down. If you do, you may end up with sharp pieces of glass in your palm. For the sake of safety, keep your leather gloves and safety goggles on for this step.
If you skip this step, you could easily slice your hand open on the jagged edge of the cut glass. To avoid getting bits of sand in your eyes, make sure that you’re still wearing your safety goggles at this point.
