Sweat soldering is not difficult but requires very careful
preparation. First, after piercing, anneal both the pierced piece and
the intended back. Put them onto a bench block and use a mallet to
insure they are both perfectly flat. Lightly sand the surfaces to be
mated. Wash both in alcohol to remove finger oils then Prip's flux
At this point, you have several choices. The first I would
recommend is .....don't use paste solder. I believe the flux in
paste solder has to bubble away and when it does, it causes vacant
areas around the remaining solder. These areas sometimes extend out
and away from the solder resulting in hollow places....and these may
even bubble up to preclude a good mate.
You can use any good self-pickling flux and cover the two surfaces
to be mated. Heat each in a direct flame to expand and relax the
flux. You can now use either pallions (snippets) or make some solder
dust by filing the edges lf sheet solder with a medium bastard file.
If you use snippets, place them randomly around the bottom surface of
the top sheet, heat until they melt and flow. You will now have a
surface with little welts of solder all over it. If you use solder
dust, scatter it evenly over the entire surface and heat the surface
enough for the flux to melt and hold the dust in place. Now place the
two surfaces together and position them.
At this point, I do not use a sweat stand! They eat heat worse than
a block of copper. I prefer to stand two charcoal blocks (or fire
bricks) on their side or on end and place the wire mat on them like a
bridge. Place the pieces to be sweat soldered onto the mat and heat
from underneath with a bushy reducing flame and keeping the flame
well away from them at first but gradually bringing it closer until
the piece begins to show red. Hold the torch at this point, moving
it around the entire base to insure even heating. The idea is to heat
the bottom sheet slightly more than the top but bring them to a high
enough temperature that the solder will flow. When it happens, you
will see the top piece slump slightly as it is 'sucked' down onto the
bottom sheet. You may also see a thin bright silver ribbon along the
edge between the two sheets. When the entire top sheet has
'slumped', remove your torch and quench.
Sounds complicated but it is really quite simple.
Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut1