Soldering Sterling domes

Gail, I have always used a self-closing tweezer to hold the two sides
together in soldering sterling domes. An ample flame with less Oxygen
and a larger tip should work better for you. You are overheating the
metal with too much Oxygen which is causing the surface change and
probably oxidation which is impeding your solder from flowing easily.
Using medium or easy solder instead of hard solder should help as
well. The large flame will allow you to get in and get out fast when
you are soldering, always the best way to avoid pitting or surface
mottling. All that is needed is a small ball of solder on a pick and
then heat the domes until the flux melts, touch the solder to the seam
and it should flow all the way around instantly, providing that the
metal is clean and there has been no build-up of oxides. Immediately
remove the flame as keeping it there won’t do you any good, it will
just cause more problems with the solder and possible surface
oxidation. If it does not solder, pickle it until it is clean, and
repeat the soldering operation. Stopping and cleaning instead of
forging on and possibly ruining your piece is the way to go. Remember
that silver solders differently than gold. For silver, the entire
piece must be heated and then you can concentrate on the area to be
soldered. With gold, you can go right in and focus on an area to be
soldered. Because of the superior conductivity of silver, the rest of
the piece will steal the heat until it has sufficiently heated up to
allow the solder to flow on the target area. Practice this process
whenever soldering sterling until you feel confident in being bold
with your torch to get in and get the job done and get out quick. It
has always worked for me in any soldering application. If a piece
won’t solder, it will usually be that the flame is incorrect or the
piece has gotten dirty. Good Luck. Alice Pittman