They call this Lesson #22 over at AMACO.com. I call it clay to plaster to glass. What you make in clay has a plaster mold made over it. When the plaster is solid…pull out the clay. Once the plaster is bone dry you can put it in the kiln, add your glass, and fire it. What’s cool is that this company sells a kit to do everything. You don’t have to hunt down the clay or plaster or even the glass. The firing schedule is pretty cool, although I never like crash cooling. Always start small with a project like this as a test so you can learn what to expect. Have fun!