Cracked glass has a classic look that makes that glass piece look aged. It is a popular style on many modern day vases and other types of small glass decoration pieces. The concept of making cracked glass is simple, but executing the steps and getting good results takes a lot of practice.
Things You'll Need
Metal paddle or crimps
Fill a large cooler with ice. Close the lid and set it aside until the glass is ready.
Put the glass piece into the kiln and let it warm up to the point that it barely starts to glow. The glass should reach a temperature of roughly 1,400 degrees Fahrenheit.
Pull the glass out of the kiln with the paddle or crimps. Be cautious if you grab it with crimps because it could cause dents in the soft glass.
Open the lid of the cooler. Hold the glass about a half-foot over the ice. Keep it here for 15 to 30 seconds or until you hear it break. The rapid temperature change causes it to crack.
Put the glass back into the kiln immediately. Let it sit for one minute. It will warm up just enough that the glass melts on the outside, which will mend it together. However, the cracks will still be visible on the inside of the glass.
If you do not have access to a kiln, you can heat up small sections of glass at a time using a torch. It is more difficult to get good results using this method.
Be extremely cautious when handling hot glass. Always wear safety gloves, boots and glasses.