Tuesday, July 31, 2012

I Don't Give up Easily!

by Janet Alexander
Technical Advisor


My last PMC Sterling Silver test didn't go so well. I experimented with embedding various materials in the sterling and ended up with melted pieces and a new metal alloy that was close to brass! Undeterred, I continued testing and testing. . . and testing. After calling in for help and emailing Hadar Jacobson, I decided to try the low-fire schedule she developed for her clays.







Before Firing
After Firing
It worked! I successfully fired the corrugated copper sheet with sterling silver metal clay. It wasn't too pretty, but it worked. The sterling silver clay's 12% shrinkage made the clay pull away from the copper in areas.

With the new firing approach and shrinkage considerations in mind, I moved on to more questions.


My Additional Tests 

I wondered what happens when various wires and tubes are embedded in PMC Sterling. All of the materials below work provided that you 1) fire the clay using Hadar's low firing schedule (see below), 2) create ways for the sterling silver clay to capture the embedded material, and 3) account for the clay's shrinkage.

Unfired
Fired
 
 1.   Copper wire embedded in PMC Sterling clay.










 




Unfired
Fired
2.   Steel wire embedded in PMC Sterling clay. 












Unfired
Fired
3.   Copper tubing embedded in PMC Sterling clay.








Fired


4.  Gold-filled wire embedded in PMC Sterling clay. What a way to add gold to your creation!   







Hadar's Low-Fire Schedule

Pre-firing (firing on a stove top is not recommended.)

Phase I
Ramp at 1800 ˚ F/1000˚ C to:
  1000˚F/538˚C (brick kiln)
  1100˚F/593˚C (muffle kiln) (I set my kiln at Full ramp)
Hold for 2 hours
Cool down to room temperature (optional). 

Phase II
Place piece into carbon inside stainless steel container with lid on it. (per Mitsubishi's instructions)
Ramp at 1800 ˚ F/1000˚ C to:
  1250˚ F/676˚ C (brick kiln)
  1325˚ F/718˚ C (muffle kiln)  (I set my kiln at Full ramp)
Hold for 2 hours

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