How do I coldwork my kilncast piece?
What kind of piece is it, and what are you trying to accomplish in coldworking it?
If the piece includes a reservoir that needs to be removed, this can be taken off with a wet tile saw with a diamond blade, or it can be ground off using rotary tools or by hand lapping with loose grit.
If you want to remove flashing on the surface of the casting—areas where the glass has flowed into a crack in the mold—diamond grinding points can be used to quickly remove these from the surface before polishing.
Keep in mind that the casting should be at room temperature for at least 24 hours before any coldworking is attempted!! This is because a casting that feels cool on the exterior may be considerably warmer on the interior, and still subject to possible thermal shock. If it is subjected to cold water, the exterior will try to contract around the interior, which will not be able to yield, and the piece may crack.
As always, we recommend taking a coldworking workshop to familiarize yourself with the possibilities. Check our class schedule and local teaching studios to find a course that's convenient for you. Additionally, if you have questions about coldworking Bullseye glass, you can post them to the Bullseye Forum.
Video lesson: Dealing with Devitrification
Video lesson: Coldworking with the Wet Belt Sander
Video lesson: Coldworking with Loose Grits
Video lesson: Coldworking with Diamond Hand Laps
TipSheet 8: Basic Lost Wax Kilncasting