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Soldering larg copper bezels


#1

I rent studio time at a local studio. All us, including the artist
who runs the studio are having difficulty attaching large copper
bezels to the copper base. By large, I mean 2-2.5" by 1.5". We cannot
get the solder to flow properly. We have tried silverwire and chip
solder, medium and easy. We have heated on charcoal, underneath on a
screen, and on solderite. My instructor, suspects that the metal is
oxidizing before the solder can flow, causing the problem. I believe
we use Borax in water as the shop flux. We can really use your help.
Best Regards, Camille McDaniel


#2
By large, I mean 2-2.5" by 1.5". We cannot get the solder to flow
properly. My instructor, suspects that the metal is oxidizing
before the solder can flow, causing the problem. I believe we use
Borax in water as the shop flux. We can really use your help. 

Yes, your instructor is correct about the oxidation. I would suggest
that Borax and water (water? why not alcohol?) is part of the
problem.

Try a nice paste flux such as Dandix, which will last much longer.
Borax and alcohol is the standard for gold, not copper, for a
reason.

The other problem is heating, usually. With copper, if you take too
long, you’ll reach the point of no return, where it will never
solder because of the oxidation.

You want to get in and get out as quickly as possible. Once you
switch to Dandix, I suggest soldering it on the tripod, spending
some time directing the flame at the underside – the large base.
Soldering together things that are very different in size can be a
challenge. So heat the larger piece first and then very quickly,
bring the flame to the bezel, and never let any part of the piece
get cold.

That should do the trick. Good luck!

What other resources are there out there? Rio Grande has a
comprehensive video out on soldering that explains the why of
everything and has graphics and close up videos.

I have a free ebook on my site on how to make jewelry, including a
chapter on soldering. I wrote it in 1992, so the graphics are
charmingly bitmappy.

Elaine
CreativeTextureTools.com


#3

Your moving out of jewellery making dimensions into industrial sheet
metal working.

Therefore you need the tools for that scale of work.

  1. you need a plumbers propane/air torch 1in dia as a minimum or a
    large oxy propane torch such as welders use,

  2. then you need the right brazing flux, also from a
    plumbers/welding supply store.

  3. with the above you will then get the heat needed and anti oxide
    film to either use silver brazing alloy, like johnson matthey easyflo
    no 1.

  4. or go down the brass brazing route.

Borax and water is not good enough once you get out of jewellery
sized work.

hope this helps.

however, you could use lead solder if the design lends itself to
this. For example the bezel could have a small bent section which
would give you the contact area large enough to make a joint strong
enough to stop it from peeling off in the setting process.


#4
By large, I mean 2-2.5" by 1.5". We cannot get the solder to flow
properly. We have tried silverwire and chip solder, medium and
easy. 

One should not use goldsmithing techniques on copper. Very much
different metal.

You need solder composition 10% silver, 20% zinc, and the rest
copper. This is not written in stone. Other formulas will work as
well. You will need oxygen/acetylene torch.

Flame should be neutral, with well formed blue tip and specially
formulated flux for copper brazing. I believe you can get all this
from welding supply store.

Speed is of the essence here. Warm up rod of solder and dip it in
flux. Heat joint until all parts are red and apply flux dipped end
of solder.

It should flow like water.

Leonid Surpin
studioarete.com


#5

Try a super-saturated solution of denatured alcohol and boric acid
and an acetylene/oxygen torch.

(shake or stir vigorously and allow the boric acid to settle and
don’t shake/stir again! you want a clear liquid to use)

Paf Dvorak


#6

Camille- Assuming that you all have enough heat for that large a
piece, you need a good paste flux to hold up under those conditions.
I’d recommend Handy paste flux.

Have fun and make lots of jewelry.

Jo Haemer
timothywgreen.com


#7

I will admit that I am out of my league here, but there may be
another way from another technology segment.

Reflow soldering. I. e. do it in a kiln.

Though I suspect your design requires asymmetrical heating, it won’t
be so simple. In that case you could get some loose firebricks and
makeshift a kiln to control your heat direction and input.

Hopes
Christopher Lund.


#8

First, some questions:

Are you trying to attach this large copper bezel to a much larger
base of copper? Are you heating the copper to be soldered from below
as well as from above (bezel and base) What fuel and torch are you
using?

I work with copper and bronze quite a lot and the one thing I can
tell you is HEAT, and lots of it! Do not use chip solder at least for
me it never works right, it melts and balls up before the copper is
up to heat and oxidizes. Use a lot of flux, and make sure your flame
is neutral - I found copper to be very touchy with this. As for
solders, I haven’t found one that I really like for copper to be
honest, but medium solder is what I use most often. However, lately I
have been experimenting with bronze solder and have found it to be
just as good if not better for copper and wonderful for bronze. I
think I got it from Rio Grande. Do NOT use the copper solders, I
bought some and tried to make some parts for a piece I regularly do
and found that when it flows it turns a weird silver color but then
when you fill or sand it it turns black, it also has very little
strength as the joint broke when the part was formed to shape.

Kaleb


#9

My students manage it all the time. We use Prips flux. Just warm the
metal slightly and spray it on until you have a nice frosty coating.
We use silver solder snippets on the inside of the bezel, making
sure to put one at the base of the bezel seam. Heat from below. Lots
of heat. If its a large setting like you speak of, we put it on a
screen and tripod, and then literally blastit from beneath right in
the centre of the backplate. Sometimes I will use old pliers to pick
the backplate up by its untrimmed edgee to minimize heat sink. As
soon as it is hot, circle your flame around the outside of the
bezeland drag the solder around the perimeter as it flows. Get a
buddy with a long solder pick (try grinding welding rods to a point)
to control any wandering solder snippets. Don’t waste time with the
gentle heating bit on large settings, it will oxidize and then you
have to start again. Your original bezel solder will prob be lost as
well, and you’ll find yourself with a 'lovely’gap. Get in quick and
get out. Let the poor thing cool a bit before you quench. We were a
lot less successful before Prips, and it helps if your bezel gauge
isn’t too light. At least 26 ga, maybe 24. And make sure your bezel
sits real flush on the backplate.

Have fun,
Linda

… In the beautiful Okanagan Valley in BC. where someone flipped
the switch and now it feels like autumn is on its way.


#10

The size you stated doesn’t seem that large to me.

In the class where I study, people often solder fairly large pieces
of copper and brass (and nickel).

For one project, a cuff with three overlaid metals, we had to to use
TWO torches for the soldering. (They happened to be oxy/natural gas,
not as hot as others.)

So I’d say, flux as usual, place silver solder as usual, and have
two people hold torches from different angles, working quickly.

Also, if possible, maybe a part can be pre-soldered on to one of the
metal pieces as in sweat soldering. Think about different angles for
arranging the pieces and bricks arranged to insulate heat.

No extraordinary measures.

I’m just a beginner (of a few years) compared to everyone, but these
are my thoughts.

Barbara in northern CA


#11

You are fighting getting the metal hot enough to let the solder flow
beforethe oxidation stops you. I started with small jewelry pieces
and had the same problem with soldering large hollow forms before I
took a class withFred Fenster. The funny thing about copper is that
the firescale will travel from a very small area that is not fluxed
UNDER the areas that are fluxed to where you are applying heat.

This is what Fred taught me. Make sure that you scrub your metal
with pumice before soldering to remove any oxidation from the metal
before you start. Use lots of flux on the entire piece and make sure
it is covered! (Look up the recipe for Prip’s flux. That is what I
use on copper and brass.) Have somebody standing by to spray more
flux as you are heating the metal to solder. Have somebody else with
a large reducing flame heating your piece as you are heating the
area you are soldering. Try to use a reducing flame if you can when
soldering.

Did I mention to keep the metal covered with flux at all times? My
two cents… =)

Gerald Livings (608) 444-9093


#12
One should not use goldsmithing techniques on copper. Very much
different metal. 
You need solder composition 10% silver, 20% zinc, and the rest
copper. This is not written in stone. Other formulas will work as
well. You will need oxygen/acetylene torch. 
Flame should be neutral, with well formed blue tip and specially
formulated flux for copper brazing. I believe you can get all this
from welding supply store. 
Speed is of the essence here. Warm up rod of solder and dip it in
flux. Heat joint until all parts are red and apply flux dipped end
of solder. 
It should flow like water. 

I’ve got to agree that soldering copper elements onto precious
metals etc. is a royal pain.

I easily soldered some copper thorns onto a mokume gane stem, with
plain old hard silver solder, the problem for me came when I
attempted to solder on some shibuichi leaves.

The copper thorns acted as a heat sink and sucked all the heat out
of the piece. I eventually managed it with a smith little torch
(running propane and oxygen), and using a lot of heat.

Regards Charles A.