I have a soldering question that I hope you can answer! Someone has
given me a bracelet to repair. It is a wide silver bangle and has a
crack down the middle. I have tried soldering with easy, medium and
hard solder, sheet and paste, but every single type of solder I try
balls up. This is the first time the solder has not flowed for me,
so I am not sure what is wrong. My thoughts are that the bracelet is
not actually silver? Could it be brass or copper with a silver plate?
How can you tell the difference?? I would appreciate any help you can
send my way!
Karyn, Usually when solder balls up but doesn’t flow a couple of
things could be wrong. One is the metal may not be clean or fluxed.
Another, and the most common when working with a large piece of
silver, it is not hot enough. Be sure to heat the sink,…the part
AWAY from the join. If that part is not hot, you are simply pumping
more heat into the piece through the join area and that could take a
long time; meanwhile you are increasing the chance of firescale. From
the sounds of the size, you should be using a large tip, like a nr 3
Smith or even a rose bud tip with many holes. You need heat!!!
Sounds like a heat issue. If the piece is heavier or larger than you
are used to you may not be spreading the heat evenly or be working
hot enough to get solder flow.
By the way if you are not sure of the metal take it to a friend or
find someone who can help. I learned a long time ago that if you
don’t know what it is don’t fire on it and if it is new to you show
it to someone who can help. You can avoid a lot of costly mistakes.
Maybe you need to heat the whole piece with precaution, with the
bigger torch tip available, bringing the flowing temperature of the
solder to the entire bangle, as silver is a high thermal conductor,
you lost the heat by dispersion if you apply the flame in just one
point of a piece of metal, let’s say (assuming that the piece is
sterling and is clean) you melt the solder but the bangle don’t reach
the same temperature. If you don’t have a bigger flame you may try to
built a kind of walls with soldering pads or charcoal blocks to help
to keep the heat close to the piece something a kiln like
arrangement.
OR, your torch is too small to get the entire piece hot enough
to get the solder to flow. Remember that silver is a VERY GOOD heat
sink and a large item takes a LOT of heat to get it and keep it hot
enough to allow the solder to flow. If the solder is just balling
up, I have a feeling that the “base metal” is just not hot enough to
"accept" the solder.
Your crack still has dirt in it! The best thing I have found to do
with Heavy bracelets is to run the saw down the crack and place a
silver wire in the space and then solder. Silver solder need to have
clean surfaces and even heat, you have to heat the whole piece
The problem is that you are just not getting the joint hot enough.
Silver is an excellent thermal conductor (the best of all the
metals), and the large bracelet is sucking the heat away from the
joint faster than your torch can put it in; net result is that you
can’t get the joint hot enough to melt the solder.
It’s clear that your flame is hot enough, otherwise you wouldn’t be
able to solder at all, but it’s just not big enough to generate
sufficient heat to get the bracelet hot enough to melt the solder. A
cup of hot coffee contains more heat than a red-hot needle, even
though the needle has a much higher temperature. Your torch flame
generates a certain amount of heat at a particular temperature. As
you play the flame on the bracelet, the heat enters the silver and
the temperature starts to rise, but it also leaks into to the rest of
the bracelet. When it reaches the edge it starts leaking into the
air. If your flame can’t deliver more heat than leaks away then the
temperature at the joint won’t rise any more.
Insulating the bracelet to minimise loss of heat to the air helps,
as does surrounding it with fire bricks to reflect heat back. A
larger flame, or a very much hotter flame will also help. The best
thing to try is a bigger flame and surround the bracelet with fire
bricks.
Karyn, Three things come to mind, all of which have been mentioned
previously. First, cut a slot along the crack. Second, clean well and
slip in a snug fitting flat wire. Third, flux, apply solder, (I
prefer little solder balls), and evenly heat using a large solder
tip. I use a Prest-o-lite with acetylene. If the solder doesn’t flow,
one of the above wasn,t done right.
In my experience, sterling that has been rhodium plated resists
solder. I have not found a way around the problem as of yet. If you
figure a way, share. LOL
In my experience, sterling that has been rhodium plated resists
solder. I have not found a way around the problem as of yet. If
you figure a way, share. L
Buff off the rhodium first.
More to the point for this thread is that even if the bracelet was
plated, the surfaces of the crack would not be. What’s needed is to
get that metal clean, use the proper fluxes, and a big enough torch
to handle soldering a piece of silver that size. Any one of those
three things, not done, could account for the problems the OP had.
