In my first testing last fall with PMC Sterling Silver clay, I tested embedding copper wire into the clay by trapping the ends of the wire with clay. Now I want to take this idea a little further.
I embedded a copper square wire and two brass round wires sticking upward from the clay instead of sideways. I had two questions:
- Will the metal clay hold the wire after firing without the ends being held in?
- Will the brass attach to the sterling clay?
I have a Microfold Brake tool that corrugates thin metal. I have often wanted to solder sterling silver wire into the creases but never got around to it. Then I thought, what if I could use the new sterling silver clay instead?!
So, I conducted two tests.
I applied PMC Sterling Silver clay to one side of the corrugated copper sheet. My questions were:
- Will the sterling clay bind to the copper sheet?
- What will happen when the clay shrinks?
I drilled holes through through the recesses in the copper and attached sterling silver clay to both sides of the corrugated sheet. Additionally, I bent the copper into a dome.
|Clay pushed through holes|
|Clay added to the back|
- Does the sterling silver clay attach better when it grips the metal like a rivet?
- Will a thick layer of sterling silver clay applied to the back of the copper the make piece stronger?
- Is is bendable after firing?
My next test was to see how well the sterling silver clay works with PMC+. The shrinkage rates for the clays are very close. So, I embedded PMC + into a slab of PMC Sterling Silver metal clay.
- Will the two clays attach smoothly together?
- Will the PMC+ sinter correctly when its fired in carbon?
- How will the shrinkage affect the piece?
I fired all pieces in two stages. The first stage was completed on the kiln shelf for 30 minutes at 1000˚ F. The second firing stage was in activated coconut carbon inside a stainless steel container with a lid (per the manufacturer’s instructions) for 1 hour and 30 minutes at 1500˚ F.. I chose to fire for 1 ½ hours because I was attaching clay to metal sheet.
The center copper wire melted into the sterling silver clay re-alloying the metal. The brass didn't attach at all and had some signs of melting. I wondered what went wrong. In previous tests this didn't happen.
I immediately tested my kiln making sure it is firing correctly and it is firing at the correct temperature. So, the extended time, 1 ½ hours, must be the problem.
The silver clay disappeared into the copper sheet! Again the two metals alloyed together.
The two metals alloyed into one puddle. It looks like I have a hot spot in my kiln as these were all fired at the same time.
The PMC + and PMC Sterling bonded fine (the inside dots are PMC+). There is a little warpage from shrinking but otherwise it looks good. The PMC+ sintered completely.
In my next tests, I will change the firing schedule back to 30 minutes and see what happens. Until next time have fun claying around!