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White foggy surface after heating sterling silver
We have used a reducing atmosphere in a small annealing furnace to remove organic staining on Sterling Silver. The material was heated at 1300 deg F for just a couple minutes. This process has worked very well in the past. However on this one piece, the sterling has turned a foggy white color. I can't get it off with acids or electroclean. Any ideas of what might be happening or how to clean the surface.Jay Burnett
Product Development - Lincoln, RI
January 4, 2008
The most likely cause of this problem is that the sterling silver piece with the defect got overheated in the oven. If the piece has a frosty look, it was in the oven too long. You would need to refinish or repolish to restore the finish. Some ovens may have a hot spot and the temperature may not be evenly distributed.
Refining & Alloys - Alden, New York