What is and isn't ok to bake with polymer clay? How about rhinestones, plated metal rings, or other findings?
First you need to determine if what you want to bake with the clay can withstand the temperature of about 300 degrees Fahrenheit. If you think it will be safe but aren't 100% certain, place it into the clay craft oven and heat the item, slowly and carefully with observation, to 250 degrees. If the item is doing well, increase the temperature to 275 then 300 degrees. If the item survives then it can be put into the clay within your design.
Please note: not all items will remain in the clay after being baked in place if they are just pressed into place--this includes rhinestones. Sometimes they work, sometimes they don't.
If you set the rhinestones or other items in a bezel with a lip around the item then it will stay in place by nature of the design.
You can press the item into the clay and bake it in place. After the item has cooled, test the bond. If the item stays in place, great, if not, place a bit of G-S Hypo cement adhesive into the recess left in the clay then insert the item back into place, cleaning up any adhesive that might ease out.
You can press the item into place, remove it, put a layer of Signature Series Poly Bonder™ into the recess, reinsert the item then bake in place. The Poly Bonder is designed to bond the clay to the item baked in place, alleviating the need to glue the items back into place after baking.
- Tammy Honaman, Author, Jewelry-Making Expert and Educator