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GLASS FUSING 101
Frequently Asked Questions
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Q.What causes sharp edges on the project?
A.Dragging is usually caused by over firing a project that is resting on fiber paper. As the glass contracts and draws in on itself the paper resists, sharp edges are the result. This edge can be made safe with file a or grinder. After grinding the project can be put back in the kiln and heat until the ground edge is polished.
Q.Why is there debris between the glass layers?
A.Too much glue. Small amounts of glue will burn off leaving no trace. (See: Glue
above for more info.) If you use an excessive amount of glue it will burn becoming sealed between the layers, leaving dark blotches. Excess glue can also cause small eruptions that will blow a hole through the glass or cause pieces to jump and move in the kiln.
Q.What are the differences between using a ceramic kiln shelf or fiber paper?
A.Ceramic Shelf:
•Fused glass will take on the texture/ pattern of whatever it is fired on. If you fire on a ceramic kiln shelf your project will have a smooth back surface. (Great for bowls, plates, fine art pieces; projects where a sleek underside is desired.)
•Ceramic shelf is used over and over again.
•A ceramic shelf is dense; it retains heat which allows the glass to pass through the critical stages slowly.
•Ceramic shelves have to be primed frequently, this can be time consuming.
Fiber Paper:
•Shelf paper comes in a variety of thickness and finishes. Generally the thinner the material the smoother the fusing surface. (Great for coasters, pins, wall art; projects where a textured back side will make it easy to glue accessories on like rubber feet, pin backs etc.)
•The thin material can be used only once. The medium material can sometimes be reused; it leaves a matt finish on the back of the project. The thick material can be used multiple times but the texture on the back of the project will be course.
•The fiber paper is porous. Air can circulate, therefore large air bubbles are less likely to form between the glass and the shelf.
•Shelf paper has to be cut to size and can be costly if you are using it every time you fire.
Q.What are the differences between ceramic molds and stainless steel forms? A. Ceramic Molds:
•Ceramic molds come in a wide variety of sizes and shapes. They have to be primed like the ceramic kiln shelf. The primer tends to last longer on a form than on a shelf because slumping temperatures are lower than fusing temperatures. Slumping occurs at approximately
•Ceramic molds are inexpensive and durable but they will break if dropped or used unprimed.
•Ceramic molds should be sanded and be
•Ceramic molds cool more slowly
than the glass. Therefore most molds are shaped so the glass slumps down into the mold, allowing the glass to contract first.
