How hard is it to solder fired metal clay? This question was asked recently on FaceBook. There were all kinds of answers - some wrong - so I decided this would be a good time to address this question.
Many of us like to combine sheet with fired metal clay in our pieces. For example, I sometimes use sheet wire for the band on a ring or solder bezel cups onto fired metal clay.
Fired PMC3, PMC+, and PMC Sterling, bronze, and copper clays - all are soldered in the same way. There is no reason to perform depletion gilding on sterling silver. The only reason depletion is performed is when you want to fuse something to sterling silver. Depletion, removes the outer layer of copper in the sterling silver leaving only fine silver which doesn't tarnish. (For information on how to deplete check out my blog on February 24, 2012.)
The only difference in soldering fired metal clay and sheet is that the fired metal clay has porosity, tiny microscopic holes. Because of this porosity, its best to close some of these holes so that the solder doesn't disappear into the fired metal clay like a sponge! Simply finishing the fired metal clay to a shine suffices. Either tumble it using stainless steel shot, polish it with a brass or steel brush, or use a burnisher in the area to be soldered.
The usual processes of soldering are important to know, like which type of solder to use - Hard, Medium, or Easy; how to flux and melt the solder to the item; and then how to clean the piece after soldering in pickle. If you would like to learn more about the process of soldering, I have a tutorial for sale on my personal website.
Until next time have fun claying around.