How to Melt Glass Bottles in a Kiln
- 1). Take off any labels still on the bottle. Soak it in water until the label peels off. Apply mineral spirits to a cotton ball and clean off any remaining glue from the side of the bottle.
- 2). Set the bottle aside to thoroughly air dry inside and out. Mix up a solution of devitrification of spray. This is a simple water and borax mixture. This spray will keep the bottle glass looking clear while going through the slumping process. Add a teaspoon of borax to a cup of distilled water.
- 3). Spray the devitrification spray on the outside of the bottle. Allow it to air dry.
- 4). Set the prepared bottle on its side directly on a kiln shelf or place it on a slump mold. A slump mold is made of fired clay and has a definite shape. The bottle will take on this shape when it slumps. Both the kiln shelf and slump mold must be coated with kiln wash, which keeps the bottle from sticking to the surface when it gets hot. Mix up kiln wash per manufacturer's directions and paint it on with a paint brush.
- 5). Turn on the kiln and heat it to 1100 degrees Fahrenheit at 600 degrees per hour. Upon reaching 1100 degrees Fahrenheit, hold the kiln at that temperature for 10 minutes.
- 6). Take the temperature of the kiln up to 1300 degrees Fahrenheit. Leave it there for a half hour.
- 7). Raise the temperature to 1425 degrees Fahrenheit as fast as possible. Stay at this temperature for up to 20 minutes. After the first 5 minutes start looking through the peephole in the wall of the kiln to see if the bottle has slumped.
- 8). As soon as it slumps, quickly bring the inside temperature of the kiln down to 1000 degrees Fahrenheit. Do this by repeatedly opening and closing the lid or door of the kiln until the temperature drops to 1000 degrees Fahrenheit. Hold at 1000 degrees Fahrenheit for 10 minutes.
- 9). Bring the temperature down to 800 degrees Fahrenheit at a rate of 180 degrees each hour.
- 10
Turn off the kiln and don't open it until the inside temperature has returned to room temperature. This could take 8 to 12 hours depending on how well insulated the kiln is.
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