Hi Dave, The possible solutions are different depending on whether
you're working on silver or gold but here are some suggestions.
For either metal, the most efficient way to solder on findings is to
hold the finding in a tweezers in one hand and heat with the other.
When the pre-placed solder begins to flow (and it helps to bur a
slight depression where you want the finding), touch down, be sure
the solder has fully flowed, and get out.
This way the finding gets no heat until the very end of the
procedure and the tweezer acts as a heat sink additionally.
Unfortunately (for me), this takes a great deal of hand/eye
coordination and I've found I can only use this method dependably for
earring posts. Pin findings not only need to be placed in the right
spot but facing the right direction and I don't seem able to get this
right. So ...
When soldering pin findings to sterling silver, I don't use a
tweezers. I flux the back of the piece and dry the flux. Then I
place the findings where I want them and carefully nudge bits of
solder so they're touching the sides of the findings. (You can
pre-flow the solder, of course, but it's another step and often the
solder blob won't let the finding stand up straight). Finally, and
this is the most important point, I follow a figure eight pattern
around the two findings simultaneously, never letting the flame
touch either finding. I usually find that as the silver backing
heats up, the solder flows around both findings at virtually the same
moment. Since using this method, I haven't had a sterling silver pin
finding melt down in years.
Unfortunately, since gold is such a poor conductor of heat, this
method won't work. You need to heat the sheet much more directly and
locally. Again, the "touch down" method described up top is best. A
slight modification, if your hands aren't steady enough, is to use a
third hand positioned so that when the solder flows you just push the
arm down. This doesn't work for me either :-).
What I do, and it's terribly inefficient but I don't melt gold pin
findings any more, is this: Pre-flow the solder where I want the
findings; use a flex shaft tool to flatten the solder blob; reflux
and dry the flux; position one of the findings and then use a third
hand so that the end of the tweezers is resting lightly on top of the
finding and then solder. The tweezers act as enough of a heat sink
so that, if I focus the flame properly, I don't melt the finding.
This is far from being a graceful or time-saving solution, but it
works for me.