Controlling Porosity in Handmade Silver Jewelry


I am quite new to Orchid and this is my first post! I make lot of
Handmade Jewelry peices with faceted and cabochon gemstones like
Amethyst, Garnet etc. I use Anti Tarnish Alloy (not copper) however
there are lot of problems, the metal still gets porous, and on
setting the stone, the border of the stone gets dark with pits and
holes which eventually appear after polishing. Can some one help in
the best method to make porosity free sterling silver peices? i am
quite new to making jewelry may self.

Adler Goug
adlergems @ uk