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Soldering silver to copper


#1

hello everyone

I’m hoping that someone can help me with this puzzle:

I am setting stones in garments so instead of making the back of a
bezel out of silver I use copper as the back can’t be seen anyway and
it’s a lot cheaper. Until now I have been setting rather small stones
so heating the copper plate from underneath on a tripod and using
self-pickling flux along with medium or easy solder sheet has not
been much of problem. But I have just recently needed to bezel a
larger stone, therefore had to use a much larger piece of copper plate
and the same soldering method doesn’t work anymore, the temperature
difference is so big that I end up melting the bezel or burning all
the flux before actually soldering the two. Now a friend of mine uses
plumber’s solder and flux for the same method and it seems to work
for him but when I tried the results are as desastrous as they are
frustrating: either the solder eats the bezel, or it ends up making a
clump the second I touch it to the copper…

I am asuming that I’m doing something wrong here and am definetly
asking for help as I am out if ideas and I really need to finish this
project.

Is there another way to soder silver and copper toghether? A
different flux or a solder? Or maybe I’m not getting the temperature
right?

p.s. the plumber solder I’m using is the lead free BernzOmatic and
the torch is a pin point propane of the same brand. I tried a smaller
more delicate torch but it can’t heat the copper enough…

thank you
regards

alexis


#2

Alexis,

Before soldering, cut out some of the metal in the middle of the
copper backing, this will reduce the amount of heat being sucked up
by the back.

Marta


#3

What size of torch are you using, and how sharp is your flame. It has
been my experience when silver soldering larger, for that matter,
medium sized pieces, that a soft flame from one of the larger tips for
my prestolite torch seems to give me the most control and
consequently, the most success.

Hope this helps.

Peace,
Richard


#4

I use Prips most of the time, from a spray bottle, add more as
needed, but it tends to cool down the surface if I over do that
aspect, you can heat up the copper then introduce the bezel to the
surface once you get the copper to soldering temperatures. If too
much oxygen gets in then you have to pickle and try again, but if you
keep the heat to it you should reduce oxidization.

Good luck.

K. David Woolley
david.woolley@unb.ca


#5

Hi Alexis,

A number factors may contribute to your problem. One is that copper
being a non-noble metal oxidizes much more rapidly than silver and
hence will more quickly exhaust the oxide-removing capacity of the
flux. Self pickling flux may not be up to the job. Try any standard
brazing flux like Handy & Harman’s “Handy-Flux” instead, used
generously. Limited torch heat from the Bernzomatic may be another,
although I doubt this would become an issue until you get to bezel
sizes bigger than say a silver dollar. For a good joint at lower heat
you might try “Easy-Flo 45” - it’s a low(er) temperature silver
solder, substantially lower than “easy” jeweler’s solder; both flux
and solder are common and should be available at your friendly
neighborhood welding supply store. By the way both these factors
work in tandem. A low heat torch like the Bernzomatic means more
heating time to bring the joint to soldering temperature, more
heating time more oxidation = more likelihood of exhausting the
flux.

Cheers,
Hans Durstling
Moncton, Canada

(come say hello at the Alpha Supply booth in The Tucson Electric
Park Show)


#6

Hi Alexis,

I understand this problem well. I had a series of pins which were
pierced out the shape of a head, “Head Pins”, and the brain section
was a bezel soldered to the copper base. I had a devil of a time
trying to solder a rather large bezel to these brooches which were
nearly two inches long.

Here is what I did to achieve success.

  1. You need a GOOD copper cleaner. I liked using Penny Brite
    http://store.yahoo.com/cooks-corner/penbritclean.html

Penny Brite completely degreases the copper, and combined with clean
flux, is essential for getting the solder to flow. Dry your copper
well with a towel. Handle by the sides.

  1. Copper eats heat, so you need a good blast. Flux your seams, you
    don’t need to flux everything. Heat the piece from UNDERNEATH. I
    usually hold my work in a cross lock tweezer, rather than the large
    trivet arrangement.

Your soldering job should go well.

BTW, I just ran a soldering 101 workshop using Hoover and Strong
wire silver solder. Great stuff!

Good luck!

-k

Karen Christians
M E T A L W E R X
50 Guinan St.
Waltham, MA 02451
Ph. 781/891-3854 Fax 3857
http://www.metalwerx.com/
Jewelry/Metalarts School & Cooperative Studio


#7

I’ve read a couple of replies to this, and it seems they mostly miss
the point. You are doing yourself and your customers a disservice by
using copper at all. Aside from the fact that your product is not
sterling, though it looks it, it will tarnish quickly, go black,
look funny, even corrode - bi-metalic action and all that. Plus all
the difficulties of soldering it, all to save 75 cents worth of
silver. One reply said to punch out the center, which might work, if
it doesn’t warp all over on you. Just buy the silver and do it right.