We were excited to hear the announcement that sterling silver metal clay was being introduced to the market in December 2011. Sterling silver is stronger than fine silver so it works well especially with rings and bracelets that take more "wear and tear" than pendants or earrings.
Angie and I ordered some sterling silver metal clay in January and decided to try it out by making some rings in the studio. We liked the feel of the clay and it worked very well in forming and picking up texture. There are several methods of making rings out of metal clay but the method we like is to first choose a ring template to determine the shape and the width of the ring band.
Then we wrap the band around a step mandrel that has been taped and oiled so the ring will come off easily when it has dried.
The tricky part of making metal clay rings is determining the shrinkage rate of the clay in order to get the right ring size. I read quite a few blogs about the shrinkage rate of sterling silver clay and noticed that some said it shrunk 3 sizes and others that said it shrunk 3.5. We decided to make our first rings 3.5 times bigger than the desired size. We used the step mandrels which are easy to work with as one has full size ring measures and the other has half size ring measures. If you want to make a ring that is size 8, you would wrap your band around the 11.5 step to factor in the shrinkage ratio.
Unlike fine silver clay, sterling silver has to go through two firings, the last being in carbon because of its copper content. The first firing is in open air, where the rings are fired at 1000 degrees Fahrenheit for half an hour.
After the first firing, the rings are buried in activated carbon. A steel ruler was used to measure a 1/2 inch layer of carbon in a steel pan.
Then the rings were set in place and another 1/2 inch of carbon was used to cover them.
Now, they were going to go into the kiln for their second and final firing. Although the directions said to fire at 1500 for 1/2 an hour, I had read on a few blogs that there were sintering problems with that short of time so we lengthened the firing time to 2 hours to make sure the silver was sintered and strong.
After working with carbon firings with copper and bronze, the two firing process for sterling silver seemed straight forward. However, we had inconsistent results with the shrinkage rate. One load shrunk 3 sizes and another 3.5. Intriguing results... same thickness rolled out, same design, same sizes, same pack of clay. We'll do some more testing and let you know what our findings are.
Once the rings were fired, it was time to brass brush, put on patina, and finish them!
Here's a ring I made!
Angie made some beautiful triple spiral rings that she was commissioned to create.
We are eager to continue creating with sterling silver clay, especially when making rings, as we know its strength will be a great asset to this type of work.