I was always under the impression that one could not ball copper
wire. So I never tried it.
I recently purchased a book called “Wrap, Stitch, Fold & Rivet:
Making Designer Metal Jewelry” by Mary Hettmansperger. In it she
talks about balling up copper wire. As if it were, oh… that easy.
So I tried it. It did not work. The only thing it did do was to turn
the upper end of the wire a brilliant red color.
So what is going on here. Can copper wire be balled up or not? My
wire was 18 gauge if that helps. And why did the end that was not
directly in contact with the flame turn red…
Yes, I regularly ball both 16 and 18 gauge wire as demonstrations in
my chain making classes. It takes a bit more heat than sterling.
Hold the wire vertically in a third hand and keep the torch directly
below with the tip of the light blue cone almost touching the end of
the wire, it will ball.
The end turns red because of the way copper oxidizes when heated. I
ball copper wire to make rivets. I dunk the wire in Pripps flux, dip
the balling end into borax, and hit it with a sharp oxy-acetylene
torch flame. I’m usually not too concerned with perfect balling,
because normally, I am going to reshape the head on my rivet plate.
The trick to balling copper is that it needs a lot of BTUs in a
hurry…
I made a basket approximately 1 foot tall all woven with hundreds of
pieces of copper wire balled on the ends. So, yes, copper wire can be
balled on the ends. The wire I used was 18 gauge. It tends not to
ball evenly and can get kind of globby looking, but if I didn’t like
the look, I’d clip it off and start again.
Maybe the trouble you’re having is with the thickness? May not be
getting hot enough.
The end of copper wires can be easily balled, with or without flux if
you have a proper flame to provide enough heat quickly and cleanly.
18 gauge is not particularly heavy, for this task. Although I do not
know the details of your specific torch, I would suggest it might not
be producing enough heat for the task. It is much easier to do with
“higher heat” mixed gas torches (oxygen plus another gas). We
(Spirig) manufacture a torch (Spirflame[tm]) which does a great deal
of this type of melting not only in copper and precious metals
(including platinum), not just for jewelry but in industrial
applications, for motor and coil winding applications in much larger
gauges. However, there are also some simple bench techniques you can
use to improve your odds and concentrate the flame you already have,
to try and accomplish this. Please contact me off line or use our
800 number to discuss this further.
Best Regards,
Gary
Gary W. Miller, Sr. Technical Advisor www.spirig.org
And why did the end that was not directly in contact with the flame
turn red.....
The vicinity of the flame provides a hot and oxidizing environment,
so the red coating you saw would be cuprous oxide. The other oxide
of copper is cupric oxide, which is black. (That is the black scale
so often seen when doing hot work on sterling silver and other copper
alloys.)
I have a hint on balling wire, not specifically about copper, but it
may help. I find that on larger wires, if I have trouble balling, it
helps if the tip of the wire nearly extends out the bottom of the
flame. To try to clarify-- you want the tip of the inner blue cone of
the flame almost touching the wire, and typically we hold the wire
from the top, ending just in front of that blue cone. If you lower
the wire until it is almost out of the bottom of the outer cone of
the flame, it will ball if it is ever going to.
If you’re using a weak torch such as a hand-held butane, this may
just not happen. Copper takes a lot of heat to melt.
Can copper wire be balled up or not? My wire was 18 gauge if that
helps. And why did the end that was not directly in contact with
the flame turn red....
Roberta, copper wire certainly can be balled up. I dip the wire end
in paste flux, and hold the wire almost vertically with heatproof
tweezers. The end to be balled is down (that’s how I do it; others
hold that end upward). Using my air-acetylene torch, I put the fluxed
end at the hot point of the flame, aiming it at very slightly above
the wire end (a useful suggestion from another time this thread was
discussed on Orchid).
When you heat copper, heat will travel through the metal, causing it
eventually to oxidize. The red you mention is probably cuprous oxide
(Cu2O). Enjoy!
When balling sterling silver (and I assume copper) I find I can keep
it from getting all bumpy and bubbly by using LP & oxygen and by
turning off the oxygen the moment the ball is formed to my liking.
The other factor besides coppers higher melting point is the source
of your copper. Jewelry suppliers should be selling you reasonably
pure copper. Hardware store, discount store ‘copper’ or electrical
wire will be a lower percentage tarnish resistant alloy.
Hardware/electrical copper wire does not forge well either.
You really need a lot of heat to get the larger gauges to ball up. I
use my acetylene torch for this most of the time, but have had
success with a sharp oxy/propane flame on our Little Torch, too. I
think the big thing is getting it hot enough quick enough, so you
don’t have a lot of oxides building up. Fluxing it with something
like Handi-flux can really help, too.
The other factor besides coppers higher melting point is the
source of your copper. Jewelry suppliers should be sellingyou
reasonably pure copper. Hardware store, discount store 'copper' or
electrical wire will be a lower percentage tarnish resistant alloy.
Hardware/electrical copper wire does not forge well either.
I hadn’t thought of that. I was using hardware store copper wire.
Plus my torch is just not hot enough. (Plumber’s torch)
Hardware store, discount store 'copper' or electrical wire will be
a lower percentage tarnish resistant alloy. Hardware/electrical
copper wire does not forge well either.
I hadn't thought of that. I was using hardware store copper wire.
I can’t say for sure whether this is accurate or not, but I wouldn’t
just take it as gospel. Others no doubt know with more certainty,
but my impression has always been that electrical copper wire is
just fine.
The other factor besides coppers higher melting point is the
source of your copper. Jewelry suppliers should be selling you
reasonably pure copper. Hardware store, discount store 'copper' or
electrical wire will be a lower percentage tarnish resistant alloy.
Hardware/electrical copper wire does not forge well either.
You say it does not forge well. I forge 4 gauge and 6 gauge round
wire into bracelets all the time. I use ground plain wire from Home
Depot or Lowe’s. I must say I haven’t any problems forging this
copper at all.
My searching on the matter reveals this copper must be 99.3% copper
or better with 99.95% being the norm according to industry standards.
Oxygen is introduced at a near 200 ppm to improve conductivity and
to remove/isolate impurities. This is modified by annealing and
forging. I suspect it’s resistance to tarnish is due to the solution
used in drawing or extruding the wire and is superficial only, for
this ability to resist tarnish does not survive annealing.
It’s true that electrical wire may be different than jewelry wire
normally because in jewelry wire there is no need to introduce
oxygen. I’m not sure we are talking about a great significance in
behavior for non electrical use.
TL Goodwin
Lapidary/Metalsmith (note, I used “Lapidary” this time.)
The Pacifik Image