I recently got asked 'what is the difference between fine silver and sterling silver?'
Silver metal clay is Fine silver!
Fine Silver is pure silver (0.999 or 99.9% pure). Sterling silver is 92.5% silver, to which other metals, primarily copper is added. These added metals make the sterling harder than fine silver. The added metals mean that sterling silver tarnishes faster than fine silver.
Sterling silver needs to be fired at a lower temp than fine silver otherwise the copper oxidises making the fired pieces fragile. So if you are adding sterling silver findings to your pieces you need to be sure to fire them at a lower temp.
I will soon be looking into the kiln firing process for silver clay and sterling silver, so once I have half a clue I'll fill you all in.
As always if anyone has any handy tips or info re: firing silver clay...please feel free to share your comments!