Glass fusing is a glass fabrication technique which involves heating glass in a kiln until it reaches a soft point, which allows the user to manipulate the glass in a variety of ways. This method for working with glass is sometimes known as kiln-forming or warm glass, referencing the fact that the glass is worked in a kiln, and that the operating temperatures are far lower than those used in glass blowing. A wide variety of objects can be produced through glass fusing, ranging from necklaces to bowls, and the craft is much easier to learn than glass blowing.
The “warm” of warm glass is between 1,100 and 1,700 degrees Fahrenheit (600 and 925 degrees Celsius). At these temperatures, glass softens enough that when pieces of glass are heated and pressed together, they will fuse into a single seamless piece. This is the underlying principle behind glass fusing. Some people use the term “glass fusing” to refer specifically to fusing glass, reserving other terms for bending and shaping warm glass, while others use the term generally to talk about any sort of kiln-forming technique.
People can use glass fusing to heat glass and fuse it with other pieces of glass to create layered pieces and patterns, and they can also explore slumping, in which warm glass is allowed to slump into a mold to create a molded piece. On the high end of the temperature scale, the glass is soft enough to be directly poured into molds for glass casting, a glassworking method which can be used to create a wide number of glass objects.
For glass fusing, a number of supplies are needed, including a kiln and tools to work with the glass. It is also important to have safety equipment like heavy gloves and fire-resistant aprons so that people can work safely around the glass kiln. Glass fusing also relies on the use of compatible glass; if the wrong types of glass are mixed, the piece can crack or explode as a result of different cooling patterns and densities.
Supplies for glass fusing can be obtained through arts and crafts catalogs and companies which specialize in glass fusing. People who are interested in exploring fusing can take classes and workshops to learn the basics and gain access to a kiln. Art and crafts centers and colleges sometimes offer such glasses, and sometimes arrangements can be made for people not enrolled in classes to have access to the kiln. Artists cooperatives may also maintain kilns for their members to use.