Lesson 1: This stuff is expensive (about $1.50 per gram for silver and $0.36 per gram for copper at the time I purchased it)!
I was very disappointed to see how tiny a 20gram lump of silver clay was. It is about the size of a stack of three quarters. As copper is much cheaper, I decided to experiment with it first. There is a new quick fire Copper Clay which hit the market in December. The quick fire Copper Clay can be fired with a torch. Which, is what I am doing as I don't have $800 to invest in a good kiln. Especially for something I haven't tried yet.
This is what I came up with during my first time using the clay (the two pieces on the top have been burnished, the four below have been fired). The instructions that came with the copper clay said to heat the piece (with a butane torch) until cherry red. Then to hold the temperature (keep it cherry red) for 3-5 minutes. I fired my pieces for 5 minutes each.
I began the firing process using a micro torch. However, in the middle of firing the third piece, I ran out of fuel! Aggghhh! I quickly grabbed my large blue propane torch (BerzOmatic "Fat Boy") and began using it. I decided that I liked the propane torch better, as it heated the piece much faster (and this canister of fuel has last for months). Not sure what is better for silver clay as I haven't tried that yet, but for copper clay, propane is my choice for torch firing.
Lesson 2: Use a propane torch when torch firing copper clay.
All of those pieces in the photograph above have been fired. I began the polishing process on two of them. One of which, (you've probably noticed) is broken. Before firing, as they clay dried on my candle warmer, the piece curled a bit around the edges. After firing, I took a pair of pliers and tried to flatten it out a little. SNAP! oops!
Lesson 3: Finished pieces of metal clay can break. Easily.
I have read that it is possible to fix a broken piece, but that will be a topic for another post. After a few hours trying to research what went wrong on the internet, I learned a valuable lesson about sintering metal. [If you are going to get into metal clay, you will want to read the article on that link as it is explained very well.] Basically, the metal particles in metal clay have tiny spaces between them. When fired, the pieces of metal that are touching bond together, but there is still space between, which makes the piece more susceptible to breakage. The longer the piece is held at the sintering temperature, the stronger the bond on those tiny pieces of metal will be.
lesson 4: The recommended firing times are the minimum time required to hold the piece together. There is a big difference between the minimum firing time and temperature and the ideal firing time and temperature.
So I went back and fired my unbroken pieces again for 15 minutes each. When you are swirling a torch and staring at a piece of cherry red metal, 15 minutes feels like an eternity. Especially when you have multiple pieces to fire. The ideal firing time is two hours, but that is not possible with a torch. I have no idea how much stronger my pieces will be, but I felt that 15 minutes was a big improvement over 3-5 minutes.
Lesson 5: Torch firing metal clay takes time. Have your ipod to help pass the time.