Convergent Series

learning, using & teaching metal clay, and other aspects of life

Sometimes, you just have to wait a while.

Posted by C Scheftic on 2011/03/29

Here’s another “silver hugs copper” piece.

In this case, once again, I started with a washer-shaped stamping from copper sheet, and added a pair of simple silver metal loops around it. I pressed those together lightly at their ends, but did not press the silver down onto the copper. I pressed a “pilot hole” in the moist clay end; once it had dried I then drilled that to size. Then I fired it as usual for silver clay.

When that was done, once again, I quickly opened the kiln door, lifted the kiln shelf with tongs, and dumped the results into a bowl of room temperature water. That cooled it quickly to handling temperature. I repeated the attempt to reheat and requench (described in my last post) but that still yielded nothing that would “peel” off.

After several more tries I finally took the just-quenched piece, and dumped it into a bowl of bubbling-hot pickle (acid). I left it there for several hours while I worked on other things. Other than, perhaps, how long I had to let it sit (because I was using the weaker citric acid pickle, not the old sulphuric acid (aka battery acid) pickle), that’s my understanding of one of the traditional metalsmith’s ways of handling just-heated copper.

I could have left it to pickle for an even longer time. (I don’t have a photo of how this piece looked at that point….) The ugly black coating was somewhat thinner, but still evident.

So I took it over to my bench (in this case, a card table repurposed for use as a bench…) got out my Dremel tool, and started trying to “grind” off what remained. I got most of it off, except for a bit that was up right next to the silver bands. I didn’t have a good attachment for getting in really close without grinding off some of the silver. (I had one, but had recently chipped it doing something else silly, and have yet to replace that.) But, at last, I was seeing most of the copper.

What did I do at that point? I reheated it! Huh? Direct heating of “fresh” copper can do some nicely interesting things. So I got out my torch again, put a quench bowl right next to my firebrick, laid the piece on that, and fired away just until it started to glow. Keeping the heat on it as best I could–as with my earlier attempts at torching it, this takes a bit of simultaneous ambidexterity–with my other hand holding a pair of tough old pliers, I swept it off the brick into the bowl. This time, at least, it did what I was expecting: colors!

Although the exact results are always unpredictable. That is, I can’t guarantee, oh, “I want a bit of red here, green there, and blue over in that spot.” But you can say, oh, “I hope I get a nice assortment of colors,” and have a reasonable hope of getting that. They’ll be brighter on the side that felt the direct fire than they will be on the underside, but that’s just fine.

I liked how the colors of this piece turned out, at last, so I added a pair of bronze jump rings. The piece will eventually tell me what it wants to be hung from and with (probably while I’m working on something else with components that remind me of this one).


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