Did you know that you can incorporate glass into your silver clay? It takes a bit of additional work (for example, making sure that the glass doesn’t shatter in the kiln), but the results can be well worth it. Below is a pendant I recently made that combines glass and silver clay. The steps that went into making it will be described below.
Before I go further, there is one caveat: bronze and copper clay are not good for this purpose. They fire at temperatures that are high enough for the glass to melt, producing a blob, instead of the lovely piece you envisioned.
Now, on to how to work with silver clay and glass. First, find a piece of glass that you would like to incorporate. I used slumped glass, with a dot of dichroic in the middle and a dot of opaque glass atop that. That glass was slumped in the same kiln that was used with the silver clay, but glass slumping is another discussion. You could, of course, use a lampwork glass bead, a bit of beach glass, or any other glass that catches your attention. The piece I chose looked like this:
I then cut out and textured a piece of silver clay to make the background. The background was 1.75 mm thick, which is thicker than most people work. The extra thickness is needed, to hold the glass.
Before the clay dried, I placed the stone where it would eventually go and cut a hole around it so that the glass would just fit. After the clay had dried, I went back in with a file and enlarged the hole. This is extremely important — clay shrinks when it is fired, and the glass does not. To prevent the glass from cracking, you need to make allowances for shrinkage. How much depends on the brand of silver clay you are using — the more the clay shrinks, the more allowance you will need to make.
I finished the greenware in the usual way, and attached a bail. I placed the glass in the opening, and put down a bit of syringe as insurance. I expected the glass to tack fuse to the silver, but a bit of mechanical reinforcement never hurts.
When it was done, the greenware, with the glass included, looked like this:
Next came firing. Firing of metal clay with glass is complicated in a number of ways. It is best to lay the piece on a blanket of fiber paper, not a kiln shelf. Without fiber paper, the glass can stick to the kiln shelf. Firing itself must be done in stages. If the glass heats or cools too quickly, it can shatter. I let the kiln ramp up at 1000 degrees F per hour to 1300 degrees, let it rest there for one hour, then ramped down at 1000 degrees per hour to 800 degrees. After that, I turned the kiln off and let it cool naturally. Note that various people advocate various firing schedules for glass. I’m just reporting the one that I used.
After the piece cooled and came out of the kiln, I tumbled and patinaed it. You might notice that one of the lines of syringe came off while brushing. This was not a catastrophe — the glass had tack fused, and therefore was firmly in place.
After that, all that remained was threading a chain.
I hope this will inspire you to consider using glass with your silver clay.