Hope some of you can answer this question. I have a customer
who wants a sterling silver charm with a flat back soldered onto
a sterling silver locket for his lady for Xmas. I can get the
commercial lockets from Rio Grande and a couple of other sources
with no problem and I already have the charm he is interested in,
but can this be done with ruining the locket? I am fairly good
at quick soldering so if speed is the only issue, that won’t be a
problem, but sterling does seem to need the entire piece to get
hot for the solder to flow properly. Really need some advice
here.
Hi Lynn, I have worked silver for 20 years and I wouldn’t try
it. The locket is probably too thin of metal to stand up to the
heat even with easy solder. Epoxy isn’t the anwser either, the
only thing I would try is a product called Stay brite, works like
a lead solder. Not a great answer but just my 2 cents worth.
Aloha Lynn, You will probably get several responses to your
question. The problem with soldering in this case is the locket.
The metal is (in most cases) stamped from very thin sheet.
Silver, as you know, has to reach the same temp., between
components, to solder. The heavier (charm) requiring the most
heat. A very touchy situation, to say the least. If I was to do
it at all, I would consider a fixture, you can buy fixture
material for oven soldering or make one of dental investment.
Make a hill of the mixture, embed the locket (making sure to fill
all the underside to avoid collapse). Cover everything except
the exact area of the charm. Position the charm and let it setup.
Remove the charm. Clear away any fixturing material that crept up
under (in the soldering area) the charm. Take the charm, use easy
or super easy solder and flush the back with solder (FYI, you
just lost 50 to 100 degrees on your second melt). Flux your
locket and position your charm, Heat the whole mass and reflow
the solder or do it in your oven. Or consider riveting it, Or
tell your customer, No Thank You Very Much. Good luck, hope this
was of help.
Best Regards,
Christian Grunewald
Precision Modelmaking
Hawaii
Lynn, (If this response is too simplistic I apologize, I don’t
know your level of expertise with silver) Just looking at the
lockets in the Rio catalogue with their hinges, jump rings &
bales all soldered on, and the engraved surface treatment on
most, I’d say that unless you’re very comfortable with working in
silver, your best bet would to use a small amount of VERY low
melt solder (I’m gritting my teeh as I say this… tin plumber’s
solder) or the solder that the stained glass people use, (along
with their complementary fluxes) and a very soft oxy-free flame.
Any of the silver solders (even the extra easy ) flow at temps
over 1100 deg and go up in less than 100 deg increments. The
chances that you could loose any or all of the attached
components are fair to good. Having said that, if you really feel
the need to silver solder the charm to the locket, it can be
done. Put yourself in a very positive frame of mind, you can do
this. 1. Pickle both pieces well, in warm pickle for 5-10 min.,
to remove any oils. 2. Rinse well, pat dry and paint all solder
joints on the locket with yellow ochre (water based yellow
ochre). 3. In order to avoid any variations in the color of your
finished piece I would then paint the rest of the locket,
inside & out, with the exception of the area to be soldered, with
the ochre. Set aside to dry. 4. Coat the charm with either Pripps
or a boric acid/alchohol slurry 5. Flux the areas to be soldered.
5. Using “extra easy” paillons (little 1/16 in. squares) melt
(flow) the solder onto the back of the charm. 6. Re-pickle,
re-rinse, re-coat and re-flux the charm. 7. By now the ochre on
the locket should be dry, if it isn’t GENTLY dry it with a very
soft flame. 8. Open the locket and place it on a mesh screen
inside down and elevate it so that you can heat form below. 9.
Place the charm on the locket ( if necessary, bind it to the
locket with fine iron wire.) 10. Begin heating the charm while
watching the pripps or boric acid. When the coating stops looking
"foamy" and turns to glass, start moving the torch from above the
piece to up under (oxymoron ?) the locket raising the temp of
both as simultaneously as possible til you see the charm "set"
down on the locket. STOP. 11. Remove the binding wire and pickle
the piece for 5-10 min. in warm pickle. 12. Wash well preferably
in an ultrasonic making certain that all flux and ochre have gone
well away.
If the fire gods have smiled on you, and the guardians of
surface treatment have been benevolent, you can buff the piece
with a rouge cloth and not harm the engraving olthough this will
take some elbow grease. If there is no engraving, polish as you
normally would.
Could you solder pegs to the charm and rivet it to the locket.
If the locket is constructed of thin material you would want to
put a heavier piece of sheet inside under the rivet head, like a
washer, unless you think you can create a large rivet head.
You can probably solder it without problems but remove any
springs used in the catch.
If the locket opens all the way, lay it flat, then you only have
to worry about heating one side. Use easy solder. Hope that no
other problems are encountered!
Hi Lynn, Is it possible to take the locket apart, solder the
charm on and then reassemble the piece? Mostly I’ve found that
when you are soldering on a thin piece. fast is not what is
needed. A soft, gentle flame and taking your time will do better.
Those hot, quick flames will just burn a hole in
the locket. Go slow and you’ll be fine. Have fun. Tom Arnold
I agree that most likely the locket is too thin to take the heat
to attach a charm. Why not rivet it in place? Solder one or two
heavy posts to the back of the charm, and drill corresponding
holes in the front of the locket. If you think the locket needs
reinforcement, you can make washers to fit around the rivets.
Hammer down the ends of the rivets from inside, and voila!
Dear Lynn, a cold join may be a good solution. Add one or two
short posts to the back of the charm and drill corresponding
holes in the locket front, turn the whole thing over so that the
charm rests on a well-padded surface to avoid flattening/damaging
it, and tap the tops out and then fininsh them with either a
beading tool or cup bur for a neat fininsh. You’re right to find
it sort of iffy - I’ve had silver lockets warp slightly from
prolonged heating.
Lynn, the more I thought about your project, I became convinced
that riveting the two pieces together is the way to go. If you
need a walk through, I’d be happy to help. Hank Paynter Brook
Hollow Studio
for soldering things like charms to thin lockets, I’ve found the
soft silver solder used for electronics is very successful and
flows at extremely low heat.
Thanks for all of the advice about soldering on the locket. You
have basically re-enforced my own opinion about the soldering and
given me an alternative that will probably let me make this
piece. If the customer doesn’t like the final result, it’s no
problem, because I collect unicorns (which is what he wants) and
I’ve been thinking about getting a locket for myself anyway.
This would just give me an excuse.
Thanks again for all of the advice from everybody. As always,
Orchid comes through.
for soldering things like charms to thin lockets, I've found
the soft silver solder used for electronics is very successful
and flows at extremely low heat.
These are tin, with a small amount of silver. While they
contain a bit of silver, calling them silver solders is a
stretch. And they are basically engineered for their
conductivity, not their strength. If you need a soft solder in
these temperature ranges, consider buying one designed for
jewelry use, where the strength of the bond, the metals usually
bonded, and the final end use, is taken into consideration in the
design of the alloy. Stay bright s one such brand. It’s not too
different from the electronics alloys, but different enough to be
preferable. Another quite unusual one is TIX solder, which also
has a companion flux sold for it (which seems to be a pretty
generic soft solder flux. but it does work just a little better
than types made for solders like stay bright. costs more
though.) This stuff looks like a bismuth based alloy, and is
marketed as “the hardest soft solder on earth”. A dubious claim,
but the stuff does actually work quite well, and melt under 300
degrees, a good deal lower than the electronics types or
stay-brite.