What is fused glass? The name says it all, fused glass is glass that has been fired in a kiln at high temperatures. The heat adheres the glass pieces together. (1100 degrees F-1500 degrees F)

There are three different temperature applications. Each one having a different effect on the glass.

Fired at lower ranges of these temperatures (1100-1250 F) is called slumping. Firing in the middle ranges of these temperatures (1250-1350 F) is called tack fusing. Firing the glass at the higher range (1350=1500 F) is called a full fuse.

You can use all of these techniques on one glass piece, only in separate firings. They add depth, relief, and shape to your piece.

What exactly occurs when glass melts? As glass heats up, it expands and when it cools down it contracts. The time in which glass expands can be measured. Different glass expands and contracts at different rates. This can have an affect on your artwork. If you use two different kinds of glass, each one having different melting temperature. Each contracting at different rates. This rate of expansion is called coefficient of expansion which is COE of the glass.

The COE had to match or it will crack upon cooling. Here are some of the procedures:

Slumping
Slumping is heating the glass until it bends over, or into a mold. The temperature for this is 1200 to 1300 Degrees F.

Fire Polishing
Fire polishing fused glass is heating glass to give it a shiny appearance, which is 1300-1400 Degrees F.

Tack
Tack is the fusing of two or more pieces of glass until they stick together. Temperature for this is 1350-1450 Degrees F.

Full
Full is the joining of two or more pieces of glass by heating them until they melt down to a flat rounded surface. The temperature for this is 1450-1550 Degrees F.

There are many other types of manipulation that can be done in a koln, like combing, fire polishing, glass casting, ect.
Here are some of them:

Combing
The combing process is the manipulation of hot glass in a kiln. Set the kiln for 1700 Degrees F, but start combing when it reaches 1650 Degrees F. When you set the kiln higher, it allows for the opening and shutting of the door. It can re-adjust the temp., so it quickly goes back to 1650 Degrees F.

Fire Polishing
In fire polishing, the fused glass is done at a lower temp. than with fusing. Your temperatures for this are between 1300 and 1400 degrees F for generally 5-20 minutes.

Remember to always polish an item while flat before you do slumping.

Some modern techniques include; sand casting and kiln casting.

Sand Casting
Sand casting uses hot molten glass poured into a preformed mold. It's a lot like casting metal into a mold.

Kiln Casting
Kiln casting is the preparation of a mold often made of plaster. It can also be made of wood, wax, or metal. After baking a cast of the model, the model is removed from the mold.