Getting started with fusing and slumping

Getting Started

Aside from the glass, the most important item you need is a kiln. Most kilns used are electric and are capable of reaching temperatures of around 1800 degrees Fahrenheit. Kilns are available in sizes ranging from less than a cubic foot to big enough to fill a room. Kilns made specifically for ceramics can be used, but it's better to have one that's specifically engineered for firing glass.

Your kiln must have the capability to accurately monitor and display the inside temperature. This is usually done with a pyrometer, a precise thermometer that is often coupled with a controller, a device that helps manage the firing of the kiln. A controller can greatly simplify the task of precisely directing and monitoring the temperature changes inside the kiln. You can get by without a controller if you're willing to keep a closer eye on the kiln, but a pyrometer that can accurately measure the temperature inside the kiln is essential.

In addition to the kiln, you need a shelf to set the glass on and (if you want to slump) a mold to help shape the glass. Shelves are generally made of clay or a lightweight refractory material, while molds can be made of clay, stainless steel, or various kinds of cements and plaster mixtures. The key is that both the shelf and the mold can withstand heating up to a temperature of 1700 degrees Fahrenheit or so and then cooling back to room temperature.

You'll also need some sort of glass separator to keep the glass from sticking to the kiln shelf and the mold. The separator can be a special kind of paper that glass won't stick to at high temperatures (called fiber paper) or it can be an emulsion that you apply to the shelf, then allow to dry (commonly called a shelf primer or kiln wash). Without this separator, glass will stick to the shelf or mold when it gets hot and your piece of artwork will be ruined.

That's it. If you have some glass, a kiln, a shelf or mold, and something to keep the glass from sticking, you have the basic ingredients to begin fusing and slumping. Add some tools to help cut and the glass and a few essential pieces of safety equipment, and you're ready to begin.

What kind of glass should you use?

You can use any glass for fusing and slumping, but some glass works better than others. Even ordinary window glass (called "float" glass by people in the field) can be used, although most people prefer colored glass like that used in stained glass work.

It's likely that you will want to combine more than one different sheet of glass in your projects. If so, then you'll need to make sure the glass you select is "compatible." Compatibility is a way of saying that the difference pieces of glass you use expand and contract at similar rates. Using incompatible glass may cause cracking or even shattering of the piece when it cools.

This tutorial is a condensed version of copyrighted material from Brad Walker's book, Contemporary Warm Glass: A Guide to Fusing, Slumping, and Related Kiln-forming Techniques.

Please click here to learn more about the book.

Click here to go on to the next section of this tutorial, which discusses glass compatibility.