Gwyn - i did some enamel work on sterling, I made two layer pieces
with a design cut in the top layer into which i put the enamel. use
hard solder on layers and findings ( lower temp solder can flow into
the enamel) i did not counter enamel the pieces and never had a
problem. the enamel had a concave surface allowing me to polish the
items after enameling. it was great fun and i had students who also
enameled this way with great success. @Anne_Reichel