The Melting Process
Pieces of glass can be melted together or “fused” in a glass kiln to make an entirely new single-piece glass art image. This process is referred to by various names: kiln worked glass, kiln formed glass, kiln fired glass, fused glass, and warm glass. The “warm glass” term locates fused glass between the “hot glass” of blown glass with a gas furnace “Glory Hole” (or the lampworker’s torch on a smaller scale), and the “cold glass” of “Stained Glass” that is not heated once the glass is originally made, but rather cut into shapes and then conjoined with lead or copper foil.
When pieces of glass or ground-up glass (“frit”) that range from the size of large sea salt to powder are placed on top of a sheet of glass and fused in a kiln, they create a new glass “painting”—or a painting entirely composed of pieces of glass. Internationally renowned glass artist Narcissus Quagliata was one of the originators of this technique and coined the term “Painting with Light” to describe the process.
If the artist wants the fused glass to have a three-dimensional shape rather than be flat, it can next be placed on top of a mold in the kiln and fired again. This additional firing would be to a lower temperature that would allow the glass to gently melt or “slump” into the desired shape.