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Sweat soldering


#1

I’m having trouble sweat soldering. I am overlaying a “small” piece
of gold on a larger sterling sheet…say 2 inches by 3 inches. I am
using a 5 torch tip–on the “Little Torch”…perhaps I need a larger
tip?

Any advice on pricing one-of-a kind pieces containing silver and gold
metals?


#2

Question: Describe the trouble you are having. I use 650 easy silver
paste solder to sweat solder thin gold sheet to silver. I use the
torch to heat the larger silver piece and mostly stay away from the
small gold piece all together. Choose the torch tip depending on the
size of the silver sheet. The 5 sounds ok as long as it heats quickly
without using up your flux. Look up Pripps flux recipe in the orchid
archives and use that. Those are just some hints, but I don’t know
the type of trouble you are having.


#3

TBPK, The #5 tip on a “Little Torch” should be more than adequate for
the job. First make sure that everything is absolutely clean, apply
flux to both metals, depending on the size of your piece of gold,
place some snipets of silver solder on the back of the gold and fuse
them to the surface, then invert and place on the silver. Now place on
a tripod with mesh screen and then apply heat from below the piece.
Heat evenly, keep your torch in motion so that the metals reach
soldering temp. The solder will be drawn to the silver.

Joel
@schwalbstudio
www.schwalbstudio.com


#4
'm having trouble sweat soldering.  I am overlaying a "small" piece
of gold on a larger sterling sheet..say 2 inches by 3 inches.  I am
using a 5 torch tip--on the "Little Torch"..perhaps I need a larger
tip? 

You need to get the “sterling silver” hot enough for the solder to
run. You may want to use a plumbers torch if using propane.


#5

I’ll coment on this as engineer familiar with having dirty hands and
muddy feet. Silver brazing as applied to jewelry has 2 basic
instruction methods. In Mexico all (?) soldering is done with propane
-air and the method involves heating the entire material,realy the
base to the soldering temperature and then watching the solder flow.
Propane air torches are not very available inthe US . I brought mine
from Mexico. In the Us the acetylene -air Prestolyte torch is the
classic , with other brands present. The flame is hotter than the
propane-air flame but the technique used is the same. The oxygen flame
whether air or propane is a lot hotter and this is the flame of the
littole torch (have 2 one for oxy-fuel one for hp air -fuel) . This
flame and torch type requires a different technique although it
doesn’t seem to be well taught to jewelers. In this case the high heat
conductivity of some of the materials (i.e. silver or copper) is
defeated witn the torch. With low conductivity materials i.e.
Stainless steel this is perfect. The little torch technique has its
place so do the air oxized torches. I think that the original
problemis best handled with the non oxigen technique. when the
teaching methods don’t cover this problems will happen. My beginning
experiences were mostly with the oxy- fuel and on real big stuff.
Jesse


#6

How is high heat conductivity of silver defeated with the little
torch? Would using the 7 tip for instance instead of a 4 then solve
the problem of the high heat in a small area. It would heat the
larger area but you’d have to be careful and keep it moving. What is
the technique that is not taught that you refer to? Net


#7

I have never used larger than a #5 tip on my Little Torch and have
not had any problems sweat soldering Sterling pieces at least 3" x 3"
of 18 gauge or even 16. Keep the flame moving but not so much that the
area that you want to bring to soldering temperature doesn’t get hot
enough.Make sure that everthing is clean and properly fluxed. Good
luck.

Joel
@schwalbstudio
www.schwalbstudio.com


#8

Hi, I like to do mixed metal overlay, and I have noticed that when
sweat soldering large flat pieces, I often seem to get one or two
areas that flux gets under a bit. I usually notice this after
pickling, and I then have to reflux, and reheat the piece while
pushing that area down. How do you get a real tight join between
two flat pieces that you are trying to sweat solder? My book says to
just melt pallions of solder on the first piece and then lay it on
top of the other, but that always seem to leave a few gaps that are
packed with melted flux. Thanks for your input. Eric


#9
    ...How do you get a real tight join between two flat pieces
that you are trying to sweat solder?  My book says to just melt
pallions of solder on the first piece and then lay it on top of the
other, but that always seem to leave a few gaps that are packed
with melted flux. 

Eric, what has always worked well for me was taught to me by an old
Zuni. Make solder dust from hard solder sheet by drawing it across a
file. Take a magnet through the filings to make sure they don’t have
any steel in them from the file. Mix flux and water together (I use
half Batterns and half water–make a paste flux similarly thin), dip
the one piece into the flux and then sprinkle the filings over the
wet piece. Tap the solder dust piece against the table to remove the
excess. Put on top of your other piece of metal, and heat the two
pieces together evenly. Your join will be almost effortless and very
smooth, even and not sloppy with excess solder.


#10
         ...How do you get a real tight join between two flat
pieces that you are trying to sweat solder?  My book says to just
melt pallions of solder on the first piece and then lay it on top
of the other, but that always seem to leave a few gaps that are
packed with melted flux. 

Katherine: Your description of making solder dust and using it is
wonderful - I’ll have to try that. I was also taught, when sweat
soldering, to bevel the edge of the top piece just ever so slightly
and you will never have solder running out from under onto your piece
to ruin it. Also, I was told that after soldering, quench in water
first before putting into pickel. By cooling the piece first, you
avoid drawing the pickle under and into the unsoldered areas in the
event that you have to resolder. Just be sure to neutralize and clean
well before re soldering.

Kay


#11

Hello All , best method for accurate sweat soldering ; remove
metal from areas under which you wish to locate your pallions of
solder [ball bur small recess ] melt your solder into the recesses
, sand or file almost flat , don’t flux too much , clamp or
wire tight , solder as usual . I will often cut away areas under
very large flat areas [decorative piercing ] If problems with
uneveness perhaps annealing metal to remove stress before soldering
will prevent unwanted movement .

Mark Clodius
Clodius&Co. Jewelers