Soldering copper

Jewelry Discussion
41

Soldering copper can be tricky. I solder a lot of copper. Sometimes
I use copper on copper and sometimes I solder it onto silver. I have
a few suggestions that have worked for me over many years of playing
with fire. Try this.

  1. Flux the copper with LOTS of flux. Copper is notorious for forming
    fire scale. Flux often burns off before the copper has reached solder
    temperature so be sure you are using the proper flux.

  2. Copper solders at an alarmingly bright red color! Don’t get scared
    and pull the flame away too soon thinking you are close to melting
    the project. You aren’t. If you pull the flame away, you allow air
    to get to the copper and you get nasty scaling and peeling as well as
    cooling of the piece.

  3. Use a big, loud, hot flame. Don’t feather the flame over the piece
    to warm it up first. Don’t mamby-pamby around with it; get in there
    and cook it! Engulf the well fluxed piece in the flame at once. The
    technique is = totally against what you were taught in jewelry
    school. The idea is to keep the air away from the copper and get it
    up to that “scary red” ASAP. You must be really brave and commit
    yourself to soldering that thing when

you first touch the flame to it. Put it in water before you put it
in the acid. It will probably have some flakes on it and you don’t
want that junk in the acid pot. This technique always works for me.
Hope you have success with it too.

Susan Maxon
Honors Gran Jewelry
Palm Harbor, Florida

42

I agree with the others who mentioned that you are not getting
enough heat on the job. Have you tried an auxiliary heat source? A
camper stove (gas ring) that you can light and put the work on
st/steel mesh over this to get the copper up to mid-heat, then use
your little torch to apply heat in spots.

But better still get a bigger torch and nozzle set-up for these
jobs.

For the solder I can also suggest ‘Easiflo 45’ silver brazing rod
which flows at around 620degC (1145degF), available usually from
plumber supplies or optical parts suppliers, or places like handy &
harman. The Easyflo FLUX is also worth a look, for all your silver
and gold soldering as well. I use the powder form and apply it midway
through a big soldering job by soldering pick.

Regarding Easyflo rods, here we can get Easiflo 55, I believe. More
silver content. But for copper to copper joins the silver colour is
probably not important.

If you intend to ONLY join copper to copper then I suggest a trial
of this brazing rod, which is used WITHOUT flux (yippee):

www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm

The phosphorus in the rod acts as a flux. It has far less flow than
silver-bearing solders, but great for running up quick 3D ‘sketches’
in copper. If the rod is too thick for your job I’d try hammering it
flat and sawing off tiny pieces.

Cheers
Brian
B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
Auckland NEW ZEALAND
www.adam.co.nz

43

I work with silver and never have a problem soldering it, but trying
to solder copper is a real hassle. I tried some of the copper
solder, but it just did not work. It was difficult to melt, and was
very brittle, so that if any stress was put on the soldered area it
cracked.

So, I went back to using my regular silver solder I was trying to
solder the seams of some copper cones. Even though I was very
careful to place the solder snippets inside the cones and to use the
smallest amount possible to get good closure of the seam some of the
solder leaked out and spread out near the seam.

I tried to get rid of the silvery streaks by contaminating the
pickle by adding some steel wool to the pickle. It worked to some
extent, but the solder was still visible, though slightly tinged
yellowish. I added more steel wool, but it did not turn the solder
into a copper color.

To compound the problem the copper plating was so thin it easily
rubbed off.

Is there something else I should be doing to get a good copper
coating on the solder?

I could grind the solder off using an abrasive wheel, but as the
cones are nicely textured, I would also be grinding off the texture.

I admire the lovely work some people do with copper—no ugly solder
marring the work, so I know it can be done.

Thanks for any suggestions. Alma

44

Hi Alma,

for brazing copper you need a different type of solder.

there are basically 2 types for silver the fast flowing capilliary
gap filling for close joints that you currently are using and the
other type is easy flo 3 which does not flow like that. its designed
to gap fill and not spread. you need to get some of this. its made by
Johnson Matthey here in the uk but will be exported to the usa and
sold there.

The other alloy is called spelter, ie ordinary brass brazing alloy
for iron. Thats a yellow colour and easily obtained from your welding
supplier. Thats the traditional alloy for joining copper.

youll just have to go and see one and talk to them about easyflo 3.

you will buy it in 1/16th thick by 18in long round wire. Roll it down
to the thickness you need.

good luck
Ted.
dorset UK.

45

Cleanliness is next to godliness

before soldering you must make sure the copper is clean clean clean.
use emery paper or any fine abrasive you have to get all dirt and
oxide off of the copper then wash in soap and water runs in cold.

copper is a dirty metal and any residue will stop the soldering
process.

copper also oxidises very quickly under heat. make sure you are
using enough flux to do the job. flux the whole soldering surface.
don’t plan of the flux to move for you. dip your solder pillions in
flux as well.

when heating you need to work quickly. if you burn off any of the
flux before the slider flows you will get a bad joint and will need
to start again. heat evenly heat the entire piece not just the place
you are going to solder. when you see the clean area forming around
the solder joint from the flux then concentrate your flame on the
joint. and get it up to soldering temperature as quickly as you can.

if you are using borax as a flux (the best for copper) grind it well
and add alcohol to it not water. the alcohol will burn off without
boiling and moving your solder around.

good luck
Les

46

Hi Alma,

Seeing as copper oxidizes so beautifully and easily, I am wondering
whether you should heat the cones, before soldering to purposely
create oxidisation, and then only clean the inside of the cone near
the solder seam and between the joins, leaving the outside of the
cone “dirty”. If this works the same way as with sterling silver,
this should prevent any solder from flowing into undesired areas.
You could also draw a line either side of the seam (on the outside)
with a pencil (graphite) to hinder solder flow. Or use rouge or
yellow ochre or white out in the same area as solder blocks.

Would be interested to hear how it turns out.

Emma

47

HI Alma, the copper solders go grey, brittle when over heated. They
have quite a low temp similar to extra easy silver solder. I love
the copper/bronze paste flux from Rio.

Aurora

48

Hi Alma,

I’ve made every darn mistake on copper that can be made. Background
on me, Spent many years as one of two artists in residence during the
summers with the Utah Shakespeare Festival. I did old Renaissance
metalsmithing demonstrations on stage. I’ve gone through the Revere
Academy, and the Tenn. Tech Universities Appalachian Craft Centers,
metalsmithing program.

I was taught the proper ways of dealing with copper and other
metals.

Copper is a metal unto itself. Many of the old ways, I’ve found
funny ways that they do not always work on copper.

Case in point. You DO NOT have to clean copper to do a solder if you
use the high bearing copper solder that is available at Rio. I’ve
tried them all, and this solder doesn’t use flux. Yes it can be grey
colored if you do not handle it post soldering properly. Here are a
few of my secrets for soldering complicated copper pieces. Only use a
bench knife or scraper and carefully scrape the surface of the piece
on the area you want to solder.

The rest of the muck will act as a nice resist. No need to use
yellow ochre. It also holds the other parts in place if it is a
complicated piece. DO NOT pickle between. I make complicated 3-D
swans in large scale out of flattened 6 ga. wire. Never have I had
them fall apart when doing repeated solderings.

Next don’t use spare or that kind of pickle. Use a nicer gentler
type.

Use Rio Pickle (I stop and get the 5 gallon drums when I go cross
country) There are others out there with the same type of
formulation. Next loose the steel wool. Just anneal a bunch of copper
and pickle the pieces before you work them. The pickle will then
charge itself. You have no idea what other contaminates are in the
steel wool. That can effect the way it will plate the piece of
copper. I’ve found a nice deep blue colored pickle will cover any and
all solders that I’ve used on copper. It is hard to blast off and you
would have to sand the hell out of it to get rid of it.

I have a chem degree, but it is in molecular bio chem. At the time I
was getting it 20 years ago, I wanted to be a Dr. But a mother of
teenagers should never have that goal. I can’t site the proper
mechanics, but give me my old texts and I can easily find it.

Copper is cheap and easy to work if you know how. Practice with it.
If you want some of the Rio solder to try, email me off list and i
will send you some. There are a bunch of copper solders out there
that promise a lot, but I’ve found them more fiddly. Also get a good
supply of iron wire that you can use to bind you cones with. It helps
to hold them in place.

Conversely the properties of copper are such that when it is heated
to temp, that same tech can help it close inward. You will need to
find something (metal) like crumpled old scrap copper to hold it up
from the inside. I have a bunch of old yard sale solid steel knives
that I use to hold things and fill them if I need more.

Lots of good help on this site. Mine is just another view and
opinion.

Aggie Missing my mountain top this summer.

49

Greetings,

I have found that when soldering copper to brass it is easiest and
fastest in the long run to tin both surfaces first rather than to
try and solder a metal to metal contact. This is one of those "when
possible situations.

For instance, if I am making a copper pendant or broach with brass
fixturesI tin the fixtures first with an easy silver solder. I
clean, sand, and flux the copper with boric acid in alcohol join the
pieces and heat the copper from below. This way the solder flows
from the brass only to the copper.

Working with copper and brass I always use a boric acid flux. I save
the Battern’s for silver but boric and alcohol works just well on
silver. If I am combining silver to copper or brass I tin the silver
first as well as the other metal, where possible, so the solder
flows solder to the solder rather than flowing a pallion of solder
to two different metals withdifferent properties.

Don Meixner

50

Thank you one and all for the great both on-line and
off-line that you sent me about soldering copper. I appreciate the
time you took to go into details about what works for you. What is
interesting is that there is such a variety of ways of soldering
copper. The major problem I have is not in getting the seams all
soldered, but in dealing with the solder that oozes out and leaves
silver splotches that mar the surface of the cones.

As contaminating the pickle with steel wool did not help, I shall
try Agness’s suggestion of pickling a lot of annealed copper until
the pickle turns blue and dunking the cones into that. Hopefully it
will work for me. Thanks again for all the help. Alma

51

Alma- I did waaaay more than my fair share of copper brazing back n
the 80s working on the Portlandia Statue. Over three stories tall and
several tons of 1 mm thick copper. The sheets of copper were only 3
ft wide so there was a lot of brazing. Each seam was hammered
together, double riveted and then brazed with phos copper rod. After
brazing we would have to re hammer and reshape each seam with auto
body anvils and sawed off croquet mallets.

Each seam too two folks. One on the inside and another on the out
side. The phos copper rod was a nice copper color and hammered
beautifully.

Have fun and make lots of jewelry.

Jo Haemer
timothywgreen.com