I’ve got a soldering problem that I had to give up on, for fear of
damaging the piece. So I’m turning to you for suggestions.
I was presented with a spectacular cast sterling cuff in the form of
a dragonfly to repair. It’s a big piece, think more Gothic dragon
than delicate fly. Probably 50g of sterling, at least. The
dragonfly’s antennae extend outward from the center and touch the
sides; they are just 18 or 20ga wire attached at two points each. One
of the anteannae is broken, not surprisingly.
So I
a) degreased the whole bracelet with Dawn and water,
b) cleaned up the break,
c) filed it flush,
d) My-T-Flux’d,
e) and tried to pick solder it with my Little Torch #4 tip and easy
solder (David Fell). And my #5 tip, twice. And gave up. The silver
"chars" the minute I touch it with the torch, and the solder ball
never flows. I think the whole bracelet is sucking all the heat, but
I can’t figure out how to isolate the wire so that I get it hot
enough to flow. Or is it something else?
I recommended that the customer take it to a jeweler with a laser
welder.
Any ideas, or am I simply trying to do something that will not work?
Not enough heat from your little torch is the problem. A bracelet
this size requires the largest tip in a prestolite (or the like)
acetylne/air torch to heat the metal mass and another torch to do
the soldering of the attennae. Before attempting be sure to inspect
for any other soldering that could come undone with the heat. If your
customer is OK with it, I would use some Stabrite or Tix solder low
temperature for the repair.
You aren’t generating enough heat, or you are allowing what heat you
do have to leak away. Surround the heaviest part with fire-bricks so
as to reflect the heat back into the work and make sure you get the
joint hot enough to melt the solder. A #5 tip seems rather small to
me; a #7 should be OK, but a multi-nozzle type will certainly do it.
The dragonfly's antennae extend outward from the center and touch
the sides; they are just 18 or 20ga wire attached at two points
each. One of the anteannae is broken, not surprisingly.
I don’t suppose you could convince the customer to just let you
remove them-- you could point out that dragonflies do not, in fact have antennae!
Chris, Most likely your decision to send out for laser welding was
the most prudent one. However, I have made such repairs by using two
torches - which you need to be set up for on your gas tanks. This is
kind of a “gunslinger approach” when done alone as you need a torch
in each hand and an eye on both - very easy to over heat. It is more
easily done with two people, each handling one of the torches.
I use propane/oxy and use my large casting torch with a neutral
flame to warm the entire piece up to where the flux goes clear and
then come in with my Meco Midget torch with the #3 tip - my second
largest - and spot heat at the joint. You will have to be extrememely
careful, of course, not to melt the 20/18ga wire that you’re trying
to solder.
If you’re doing this alone pick soldering is out of the question and
you’ll have to pre-place the solder which means unless your joining
parts and heating are perfect the solder can easily run away from the
seam in question. With two people involved pick soldering is the
better bet.
Hello Chris, Sometimes it is very difficult to solder a tiny piece to
something large. You are not alone in this. What about soldering a
wire to the small antennae, drilling a hole in the body of the
dragonfly and using your new wire as a rivet? Somehow, there is
always a way around the problem. Take care.
If your customer is OK with it, I would use some Stabrite or Tix
solder low temperature for the repair.
Or better, instead of messing up the bracelet with tin/lead or other
"soft" solder, just because you’re not equipped to do it right, You
might consider jobbing it out to someone who CAN actually do it
right. Rick is right, you need a bigger/hotter torch for something
like that. Or other technology, like a tig or laser welder. If you
don’t have that, and the experience to do the job right, please don’t
risk the bracelet on an attempt you may not be able to do. That’s
fine for your own products, but not so much when it belongs to
someone else. Those soft solders, tix, staybright, etc, while they
have their uses, should be considered options of last resort. They
have nowhere near the strength, appearance, or integrety of a proper
silver solder, and once used, make a proper job almost impossible at
a later date (well, to do it right you then have to remove the old
soft solder, which can be a major PITA.)
Thanks Rick, and all who responded. I think my oxy/propane Little
Torch is just not cut out for this job, so I’m going to leave it to
someone with either the right torch, or a laser. I’m afraid if I get
the temp of the rest of the bracelet up by building a firebrick
furnace, I’m going to watch the wires ball up and melt!
Its always difficult to say without seeing the piece. But Tom’s idea
is interesting. I might modify it this way. Use square wire, ball up
the end of the wire, then cut half that ball away so you have a
tulip shaped end. Not big. Drill a blind hole just enough to
accommodate the largest diameter of the tulip. Insert and then hammer
the surrounding metal onto the tulip, capturing the stem of the
tulip, the square will help prevent rotating.
But yeah, laser is the way to go on something like this. You CAN sub
it out, make a buck and still look good to your customer. I’m not
seeking trade work but I would laser something as a favor for
orchidians.
Depending on the size of the silver bracelet, and it sounds large
and massive, soldering a tiny piece with a Little Torch is not going
to work. Silver is a prima donna of metals. It likes having all sides
touched and caressed with a torch tip.
A couple of good suggestions have been noted here, such as building
up fire bricks to reflect back the heat to create an “oven” effect.
Having a laser welder as one of the suggestions is also a smart idea.
For true versatility in soldering, use both oxy and Acetylene if
you can. A Little Torch is perfect for the tinier more pin point
aggressive zapping for gold and silver.
Have a Smith Acetylene /air for the larger pieces your
fabricating which will require a Y connector on the fuel to join to
the oxy part of the set up. Use tip #4 or #5 for more heat.
Little Torches with the tips 1-4 have a small industrial ruby
impregnated into the tip. For heavier gases, such as propane, this
tip will get clogged and you will need to use the tips 5 -7 only.
Acetylene poses no issues for your fuel and oxy consumption.
Heat around the piece first and then heat the silver up. Warming
the silver up first will keep out oxidation issues by allowing the
flux to do its job. Then go in with the torch. By that time the
solder will flow.
Solder. There are many flow temperatures out there from lots of
companies. Here’s just a few. I researched different suppliers and
the flow rate of round silver wire solder. The ranges flow rate
temperature differences are quite wide.
Regarding the use of Tix and/or other low temp solders, I’d avoid
them if at all possible because a) there is nearly always a better
way to get the job done, and b) if you do it, the next person to work
on it may not be informed of it, and will most likely be saying
unkind things (under their breath of course where no one would hear!)
as he performs more repairs than expected.
Maybe we should institute a marking requirement when soft solder is
used??? hahaha
Noel, I have to put my entomology hat on for a moment and say that,
technically, dragonflies do have antennae - they’re very small and
hairlike (setaceous), but you can see them in front of the
dragonfly’s eye in your photo. They actually seem to aid in sensing
air currents, helping the dragonfly direct its flight. All that
being said, you’re quite right to point out that the antennae on
"dragonfly" jewelry are often ridiculously exaggerated; they usually
look more like owlflies. My other peeve is when dragonflies in
jewelry are depicted with “tails” that curve to the right or left,
as the real critters hold them straight out (unless they’re
mating…)
Back to the thread, Chris, the phrase that worries me about your
problem is that the “silver ‘chars’” when you apply heat…is there a
possibility that your cuff is not silver, or that some components are
a different metal?
I thought Noel’s idea was the best yet :-), but on examination I
think the artist intended this thing to be a very strange butterfly.
Anyway, I had the same reaction as Jesse to the strange char-ing,
but the whole bracelet behaves and reacts like silver in all other
tests. I cleaned it up (it had been unworn for years, and got a bit
mucky with the soldering tries) and it really is a lovely piece. I’ll
be seeing the owner next week and wiil return it to her with your
recommendations.
I’m off to “Beyond the Basic Bezel” at Metalwerx this weekend. Back
to making shiny LITTLE things with my Little Torch!
