Easy Glass Fusing and Slumping Revealed

A kiln is used to make the glass molten and to join two or more pieces of glass. This process is also known as kiln-forming. These pieces of glass are designed in a layered manner in a kiln. Through several firings a new piece of glass is created, formed and shaped.

Before you begin your venture into fusing be sure that you know and practice the art of cutting glass. Also find out about the different types of glass available for these processes. There are so many various types, textures, shapes and forms that can be used for fusing.

What occurs when glass melts? As glass heats up, it expands and when it cools down it contracts. The pace at which it expands can be measured. Distinct glass expands and contracts at various rates. These rates could have an affect on your artwork if using two dissimilar kinds of glass, each one melting at different temperatures and then each contracting at various rates. This rate of expansion is referred to as the Coefficient of Expansion which is abbreviated and called the COE of the glass.

Remember, all glass is not created equal and when heated and cooled the COE has to match or it will crack upon cooling. See Glass Compatibility.

When glass is heated, it softens and if more heat is applied, it begins to melt and flow. When two or more pieces of glass are heated together at first they will stick, or tack together. When heated further, they will melt together, flatten out, and become one solid piece of glass. Be aware of your schedule and placement of glass pieces to avoid air bubbles . Try adding a bubble squeeze to your firing schedule.

The temperatures below are for standard fusible art glass. Some kinds of glass may require different temperatures. Each kiln is different and unique, so keep a firing schedule . Make notes at what is happening with your kiln and adjust accordingly. Just remember that what works in one kiln may not necessarily work in another.

I am often asked "When is it safe to open the kiln?" It is important not to open the kiln until it has cooled down. For more information about when it is safe to open the kiln, please refer to the " Open Fusing Kiln " page.

To view a walk through and instructions on a firing, please check out the "Fused Glass Instructions" page. It will give you more step-by-step information.

These procedures are listed in order as to temperature. These are just guidelines!! To find out what is happening to glass during the heating and cooling process, check out the page on glass zones .

Slumping – Heating glass until it bends over or into a mold. 1200 to 1300 Fahrenheit.

Fire Polishing Fused Glass – Heating glass to give it a shiny appearance. 1300 to 1400 Fahrenheit.

Tack – Fusing two or more pieces of glass until the glass just sticks together, with each piece still keeping its own individual texture and character. 1350 to 1450 Fahrenheit.

Full – Joining two or more pieces of glass by heating until they melt together forming a flat rounded surface. 1450 to 1550 Fahrenheit.

I hope this has helped you understand the difference between fusing and slumping. Fusing is melting the pieces together. This can be a tack fuse, where the pieces look almost like they are just glued together, or a full fuse, where the pieces are completely melted into one solid piece. Slumping is done at a lower temperature, and the glass slumps or bends over or into a mold or other object. Draping is similar to slumping, but instead of sagging the glass into a mold, it is allowed to slump over an object.

The following video shows some fusing and slumping techniques. Watch this informative video on fusing and slumping glass. The video can be located on YouTube

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