Soldering stlg silver bangle with mouth blown torch
Hello,
I would be very grateful for some advice.
I have been trying to solder together the ends of a 6mm x 2mm
sterling silver wire, to form an 8" bangle. I have had success with
this before but it’s just not happening at the moment. I am using a
mouth blown torch and have total success with smaller pieces, but
this is difficult.
The solder just won’t run as I don’t appear to be getting the silver
hot enough. It’s not changing colour and nowhere near red. I have
the piece surrounded by charcoal and a ‘wall’ at the back to prevent
heat loss. I am moving the flame, (sometimes concentrating on the
join, other tries on the whole piece). using the hottest part of the
flame. But still nothing is happening…
Any suggestions would be much appreciated.
Best wishes
Judy
Hello Judy,
You need more heat and I suspect that the mouth blown torch may not
produce the temperature you need. Have you tried a fireproof cover
placed over the charcoal and ‘wall’? It might hold the heat enough
that you’ll have success.
Another idea is to use Argentium sterling. One if its nice qualities
is that you can solder it much like you would gold, in that it does
not dissipate the heat so fast.
Judy in Kansas
Forgetting the argentium since its not what you have, and knowing
the capacities of mouth pipes it is perfectly acceptable to use it to
do your simple join: First reclean and scrape any old solder, flux
glass and whatever else may be sticking to the metal (oxides, etc.)
off the ends and pickle. rinse well and neutralise it with sodium
bicarb, rinse- dry and start again. Sand or otherwise expose clean
silver on all parts of the join. Make ready your soldering fixtures
so you can heat from all sides (using a tripod with nichromium
netting works extremely well with a mouth pipe).If you don’t have a
tripod, have your charcoal fixtures cleaned and ready to prop up the
ends and create a wall to reduce the oxygen in the atmosphere around
the piece. Bind the ends of the wire or otherwise clamp them
together. Warm the metal. Apply flux : you may want to use a paste
as its a good indicator of temperature and goes clear when the flux
is near the flow point of most “hard” solders. Handy flux, Hoover and
Strong’s’ FreeFlo" proprietary paste flux, Goba (in the EU),and
Dandix are all reasonable brand names, or A product I love for all
flux and firecoat applications :Cupronil- (its a spray on liquid that
prevents firescale and is a flux all -in - one, goes on absolutely
evenly, and one can build up layers on warmed metal to make the
firescale preventative extra effective and the flux action extremely
free flowing. but any flux you have that is not contaminated will
work. Place the paillion on the join once the firecoat (if you use
one) has formed a skin, and the flux has clarified. Apply full heat
from the bellows pumping action and concentrate it around the join
until the flux glass liquifies and then you see the paillion begin to
melt. Once the melt happens and it runs through the joint remove the
heat to check the joint but don’t put the flame out yet, if the join
is not sound, you may need to quickly reflux and add more solder. If
it still fails- make sure your ends are flush- file the whole off
with a bastard file, so clean metal is exposed. Get a new
brush/applicator (if using a paste type flux) and apply clean flux
or pickle, neutralise, rinse and dry the join, bind or clamp as
needed to hold the ends perfectly together with no gaps. Warm the
cleaned metal and spray on or otherwise apply flux to metal and using
a clean pick ( preferably of titanium in a wood handle as solder will
not stick to Ti, and one can pre-bead the solder and/or) move the
solder bead into place if you have trouble with the paillion as it is
or move it around with a pick as necessary if it slips out of place
from the air pressure of the pipe. The solder should run into the
joint. At that point remove all heat. Check for soundness.
Remember, solder is not caulk! It will not fill gaps in the metal
and the metal itself must be clean and oil free, the solder too must
be clean and not dirty. If you don’t cut many paillions at once into
a container it is likely the solder sheet becomes dirty and
fingerprinted. Use an alcohol wipe and clean the sheet, then cut your
paillions into a holding container. If you use stick solder (wire
solder) wipe the stick with denatured (ethyl) alcohol on cotton wool.
The mouth pipe is and has been perfectly effective for many many
centuries and was my first soldering tool for silver gold and small
Pt group wires (filigree) or cloisonnes when enamelling. That isn’t
the problem. Ensure the flame is close enough to the work and warm
the metal. Don’t think it the same as a torch with which you have to
move it over the entire area constantly to do even hit-and-run
soldering. the flame must be constant- that comes with knowing your
pipe and the thickness of the metal being worked. One thing to do to
assist in a faster sound joining is to run the sheet of solder
through a rolling mill to thin it as much as possible before cutting
the paillions. With an 8 mm piece of metal (x 2 mm) you may need 2
small paillions or beads of solder to flow and fill the join cleanly.
You don’t want to have to clean up excess solder from overflows. If
it does overflow from too much solder in whatever form, you should
use a copper braid to absorb the excess but that requires reheating
the joint and you can detach the ends this way quite easily. So
balance the equipment and consumables. ensure on your first
re-attempt that all parts are clean and oil free, you have pre-warmed
the metal and built a firecoat keeping heat from the blowpipe on the
work, When the flux starts to create glass, place or move the
paillion into place (or touch the heated joint with wire solder).It
should immediately flow into the join at which time you back the heat
off quickly. test it and it should be a done deal! I can’t stress
enough preheating, using the right flux and firecoat in an
appropriate quantity given the work, the amount of heat you direct
onto the work before you apply the paillion and the point when you
back off the heat all contribute to one’s success using a blowpipe
particularly with natural/city gas line run to the assembly. If you
master the technique it is the safest and most time tested way to
solder without having to deal with an Oxygen/Fuel set-up, refiling
tanks or rentals and insuring one’s studio when it’s your livelihood
and the building or area in which you live has restrictions on the
allowed torch types or soldering set up ( most “regulative bodies” do
not have problems with butane torches).
Much heat can be generated from a basic brass blow pipe. It can be
reamed to allow more air to flow through. The mouthpiece must match
the capacity of the pipe though. Having an effective flux and
firecoat in one product (like Cupronil if a liquid is desired) Handy
flux or Goba, if a paste or there are gels, or you use an oil for
repair are the best for both soldering and protecting the metal
(particularly silvers) from stain or scale (oxides result from a
non-reducing flame) as with a blowpipe with which you are controlling
not only the flame and direction but directing the solder to the
work. Once you have practised it and become proficient, it is a great
skill most never even try as it is not taught in the US and the
America’s but is still found in many goldsmith’s shops in Europe, the
Occident and the Orient. I hope you will not give up on the blowpipe
as I personally wish more would learn to use the method. If you are
using propane keep in mind the heat will be lesser than acetylene,
and natural gas. If I can be of further assistance please contact me.
rer
thank you so much R E Rourke (and Judy also) for your reply to my
question. I really appreciate the time you took to help me. There is
lots for me to do and learn, and I will certainly go on using the
torch I have. It will take a bit of time to get some new equipment
and go through the possibilities. The tripod, soldering technique,
cleaning is all something that I can work on. I will come back to the
forum and let you know how I am getting on. Many thanks again. Judy,
in France.