I been doing stained glass for about 5 years. I have an acquaintance that is an artist at pottery. I'd like to ask her to do a couple of molds. Would someone be so kind as to post ingredients for a ceramic mold?
Also, will her ceramic kiln work for slumping or should I see my instructor for use of her glass kiln?
Appreciated,
Donna aka chattin'
mold ingredients
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Ron Coleman
- Posts: 468
- Joined: Sun Mar 09, 2003 3:20 pm
- Location: Columbus, Ohio USA
Just about any clay will work for slumping molds. I've used white clay, terra cotta, and raku clay. The Raku clay will give you a little better mold strength and a little less shrinkage while drying and bisque firing and it will have better thermal shock resistance.
About the only problem I have with making my own molds is warping as they dry. Slow and uniform drying will help reduce most of the warping.
Remember that most ceramic molds are made to slump "into" and not "over" because glass shrinks more than ceramic.
Drill some vent holes around the bottom at the lowest points to let out any trapped air. Drilling dry clay is easier than bisque fired. The holes only need to be 1/16 inch diameter or less.
You don't need to do a really high fire bisque for glass molds, I fire to 1700 f in 4 hours and they seem to last forever.
Make sure to kiln wash the molds before using them the first time. If you don't slump at high temperatures (+1300) the first coat of kiln wash will last forever.
A ceramic kiln will work but will require some experimenting to find the best time and temperature settings for firing glass. I'd go for a glass kiln if this is your first time fusing and slumping.
Ron
About the only problem I have with making my own molds is warping as they dry. Slow and uniform drying will help reduce most of the warping.
Remember that most ceramic molds are made to slump "into" and not "over" because glass shrinks more than ceramic.
Drill some vent holes around the bottom at the lowest points to let out any trapped air. Drilling dry clay is easier than bisque fired. The holes only need to be 1/16 inch diameter or less.
You don't need to do a really high fire bisque for glass molds, I fire to 1700 f in 4 hours and they seem to last forever.
Make sure to kiln wash the molds before using them the first time. If you don't slump at high temperatures (+1300) the first coat of kiln wash will last forever.
A ceramic kiln will work but will require some experimenting to find the best time and temperature settings for firing glass. I'd go for a glass kiln if this is your first time fusing and slumping.
Ron