QuestionIf i wanted to fire something in a kiln with stones in it, how hot can it get?.. would they crack?... Or is the temperature different for each kind of stone?
AnswerHi, Shelly. Thanks for the question.
The best I can say about how hot can it get is included in these two fine articles on the web. I could copy and paste but it is better for you to go and read this information. Please note, the sites are not about precious metal clays or enamels but concern casting in place of gemstones. Casting in place is a method used extensively today to produce lower cost jewelry with gems. The lost wax method of casting is used and stones are placed in the wax models. When all goes through the wax removal and heating in the oven(a kiln of sorts) then the mold is filled with precious metal, the final product has gemstones in the metal just as planned.
The secret is not what temperature for what stone but what stones in the first place will work. Also, the temperatures are lower than normal and controlled quite closely with a long cycle of heating up and cooling down is used. Why? Heat shock is what makes gemstones either look like fried marbles or simply shatter into pieces. All must be heated uniformly, not too much heat on one side of the stone while the other side is not yet heated up. Sudden changes in heat must totally be avoided since that is the most severe form of heat shock and destroyed gemstones.
As mentioned, these articles are about casting jewelry with stones in place. However, the information is there to help you along the way.
http://www.shorinternational.com/CastStoneInWax.htm
http://www.srs-ltd.co.uk/technical/datasheet_gemstones_united-pmr.html
Shelly, concerning pmc and enamels, you will need to see what folks more familiar with these materials might say or do. One resource is the how-to articles in The Jewelry Artist Magazine. At the web site you can search archives and see well presented articles.
www.jewelryartistmagazine.com
or, same site at old address: www.lapidaryjournal.com
I certainly hope this helps. God Bless and Peace. Thomas.
