Creating an Alloy by Mixing Silver Clay and Copper Clay

Quite a few disasters happened when I fired copper and silver clay together. Here is an example:

What I think may have happened, is that the copper and silver created an alloy, and the hold temperature was too high for that alloy. When you alloy two metals, the melting temperature of the alloy will be lower than the melting point of each of the pure metals constituting the alloy. For example, fine silver melts at 1760°F; copper melts at 1980°F; but sterling silver (which is a combination of 92.5% fine silver and 7.5% copper) melts at 1640°F.

However, I was curious to see what kind of an alloy can be created by actually mixing copper clay and silver clay, wet, and firing them together. I mixed copper clay and low-shrinkage silver clay.

I rolled it 3 cards thick and cut a circle, ¾” in diameter.

I fired it with a batch of copper clay, making sure there were no bronze pieces in the box.

It blistered badly, so obviously the temperature was too high. The shrinkage was about a third.

Next, I sanded it as much as I could to see what color it was.

Here it is, next to copper and bronze.

And here it is next to copper and bronze painted with Baldwin’s Patina.

The ratio I used was 6 parts copper to 4 parts silver. Other combinations probably will yield other colors. Another thing that will require some experimentation is finding the right temperature for firing these alloys.

One question I ask myself is: is the difference in colors distinct enough to justify all the effort? Another question is: Wouldn’t it be possible to achieve the same colors at significantly lower cost by using combinations of copper and bronze?

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