To explore the possibilities of glass casting you can creating a thick block of glass using various compatible glass components.

     A clear glass box is constructed by cutting a square base and gluing 1” high glass strips to the sides. Once the glue is set, 1/8” thick fiber paper strips are wrapped around the sides to act as a glass separator as well as a help in holding the box together to transfer it into the kiln. Stainless steel straight pins are used to hold the fiber paper in place. Be sure that the pins do not touch the glass as they will fuse into it when fired.

     Once your box is ready you can start filling it with your design. These are a great way to use up you small compatible glass scraps. Thin pieces of vitrigraph can melt and conform around the glass pieces to form interesting veins throughout your block when fired. Because there will be a lot of air between all the small pieces, you want to mound up your glass about 1/2” higher in the center than the walls.

     Remembering that glass wants to be 1/4” thick so to achieve a thick block we must place dams around the piece to keep it from spreading and thinning out. If you are doing a bunch of blocks at one time you may butt them against each other and then dam the outside of the whole group.

     Because you are creating a thick piece you will be using a very conservative firing schedule. The thicker your piece the longer an annealing cycle is needed. Due to using small pieces of glass, air can get trapped and an excess of bubbles can form that will over power your design. A slow ramp up in the first firing stage and a 30 minute hold will allow air to escape. This is typically referred to as a bubble squeeze. You will also notice that the cool down cycles are very slow. When glass is this thick it needs longer to cool at a more even temperature through the piece.

Open Faced Casting Firing Schedule:*

Ramp Rate Target Temp. Hold Time 300 dph 1200 30 minutes (allows air to escape) 450 dph 1450 - 1500 20 minutes (full fuse) afap 960 60 minutes 75 dph 700 30 minutes 200 dph 400 no hold OFF allow kiln to cool on it’s own to room temperature

     After firing, there will tend to be needle sharp points along the outside top edges. These are due to the glass hanging up on the fiber paper as it melts. These can be ground off and the piece can be placed back into the kiln and fire polished.

Fire Polish Firing Schedule: Ramp Rate Target Temp. Hold Time 300 dph 1300 5 - 10 minutes afap 960 20 minutes 200 dph 800 10 minutes OFF allow kiln to cool on it’s own to room temperature

     The uses for this process are endless. Small thick table tops, thick glass tiles, let your imagination go wild.

* All firing schedules are meant to be used as general guidelines for firing System 96 glass. 90 coe glass will generally need to be fired at a slightly higher temperature. All kilns varied and you will have to perform experiments to see what temperatures will give you the desired results. Keep firing logs for every firing you due to help diagnose problems and also to log your successes. Goess Studio is not responsible for any and all damages by users of this information.

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