Martina's Glass Studio
3814-1/2 McCorkle Ave. SE
Charleston, WV25304
Phone: 304.925.2355
Fax: 304.925.2355

 What is Glass Fusing?

Glass Fusing often is referred to as working with "warm" glass, which lies midway between the extremes of glass blowing ("hot" glass) and stained glass ("cold" glass). Fusing involves use of a kiln to produce a temperature around 1500 degrees F to cause various pieces of glass to join together and/or to enable the artist to slump or otherwise manipulate the glass. Slumping is the use of heat in making three-dimensional shapes, such as bowls, bracelets, candle covers and wall art, by having the glass conform to a pre-determined form.

Four types of glass are used most in glass fusing: Opalescent glass, which is opaque but colorful; Cathedral glass, which is transparent and usually colorful; Iridized glass, which can be either opaque or transparent glass that has been coated with tin to give it extra surface color; and dichroic glass, which is a glass coated with brilliant metal oxides that frequently seem to change color as the viewing angle changes. We also use Wasser Glass, a unique opaque product in solid colors.

The coloring in the glass we use is created by the glassmakers by adding various chemicals and elements to the silica mixture used. We purchase the glass in sheets of varying thickness, or as powder, frit (crushed glass), stringers (thin rods) or confetti (small, thin pieces of glass).

The various glasses used in making an item must be compatible, that is they must have the same expansion and contraction characteristics when heated and cooled, or the object will crack upon cooling. Also, glass has to be heated slowly and then has to be cooled slowly to provide for an annealing process.

Different temperatures and heating speeds create different results. And although modern computer-controlled glass fusing kilns usually achieve reasonably predictable results, each piece is nonetheless different.

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