Solving an art glass mystery: kilnformed glass
I was speaking with a customer the other day about a gorgeous Kristy Sly bowl and she asked me how the artist was able to make the glass bend into such an exquisite shape while merging differing colors together. Sure, simple. Well maybe not so, but I do know the answer. Kristy uses a glass working process called kiln formed or warm glass. This process requires working with glass that has been “warmed” to between 1100 and 1700 degrees Fahrenheit. The quotes are for the ridiculousness of that temperature. It’s obviously crazy hot as a temperature in our everyday world but when you consider that glass blowers are working with molten glass that is over 2000 degrees Fahrenheit warm becomes an acceptable and proper description.Warm glass techniques are usually done in a electric kiln, similar to the ones used to fire ceramics. There is an electrical controller and a pyrometer to control and measure the temperature inside the kiln. Fusing, slumping and casting are all warm glass or kiln-formed glass techniques.
Glass fusing is the process of joining two or more compatible pieces of glass together into one solid piece. As heat is applied to the glass pieces they become soft and more fluid until they flow or fuse together to form the final piece.
Slumping is another warm glass technique that uses a mold to form the kiln-heated warm glass into its finished shape. The sheet of glass is heated until it sags into a mold and voila there you have it. What gets really interesting is that fused glass can also be slumped so the combinations and the results are only limited by the artist’s imagination and skill.
Kiln-formed or warm glass--the name is just symantics. What artists like Kristy Sly can do working in this process, however, is truly inspirational. Please take the time to click here to see more examples of Kristy Sly’s kilnformed glass on her page at the Red Elephant Gallery.











