Occasionally I have this problem and thought I would ask for some
expert advice. I fabricate quite a few Sterling silver half-round
bands on a regular basis… Sometimes I find that I get pitting
along the solder seem during the finishing/polishing process. I may
make 50 rings that turn out fine and then have 5 in a row that I get
pitting (always in the seam) and can’t figure out why. Has anyone
had this problem? I prepare the joining ends so that the connection
is sound and there are no voids. The metal is clean when I
solder…and I use plenty of flux… Are there any suggestions as to
what I’m doing wrong?
It can drive one crazy when they’re at the polishing stage only to
find that they have to saw through, resolder, and refinish!
I have this problem and thought I would ask for some expert advice.
I fabricate quite a few Sterling silver half-round bands on a
regular basis... Sometimes I find that I get pitting
Andy, there are several things I can think of that might be causing
this… Overheating can do this, dirty solder, and contaminated flux
as well could cause the pitting. Just guessing, I’d vote for either
uneven heating causing one side of the joint to get hotter than the
other, causing a “boiling” of the solder or just general overheating.
Using the wrong flux or contaminated flux can do this too… if this
(and I would presume so for a ring joint) is a hard solder make sure
you have a hard soldering flux. It might be making the pitts. I
personally like the Batterns self pickleing.
I prepare the joining ends so that the connection is sound and
there are no voids. The metal is clean when I solder...and I use
plenty of flux... Are there any suggestions as to what I'm doing
wrong?
I am assuming that then you saying that there are no voids, you mean
it. If that the case than you are overheating and burning out zinc
containing in solder. If joint is fitted less than perfect, in case
of silver, an oxygen absorption could be a contributory factor.
There are also could be a problem with heat application pattern,
which causes localized un-intendent overheating. If silver is even a
smidgeon below the sterling standard, it could cause problems as
well.
Most solder pits are caused by over heating or boiling the solder. I
always apply my solder to the inside of the shank and at the very
last moment when the ring is hot and at solder temp. to keep from
over heating the solder. Also over polishing can open up pits and
drag them out. Try to use a finer emery before buffing so you can
use a lighter touch with the buffing wheel.
I just hate having to deal with pits!!! I am the world’s laziest
jeweler and hate to re do things so I make every effort to get it
right the first time.
I find that if I keep my torch tip really clean I do not have that
problem. I just put mine in the ultrasonic overnight to soak and in
the morning give it a quick buzz and a blast of steam and I am good
to go.
The pitting is in the the solder, therefore reduce the size of the
seam and keep the amount of solder that you use to the absolute
minimum. Silver loves to expand when heat is applied so use binding
wire to keep the joint from opening up during soldering. Gently heat
your ring until the solder flushes throughout the seam, never over
heating the solder. Before filing, sanding and polishing your ring
you may wish to burnish the solder seam to remove any imperfections
in the joint.
Pitting also comes from heating and melting the solder before you
apply it to the piece called “tinning”. If you do this it generally
burns some of the alloy out creating the pitting on the object
intended.