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Copper oxidation


#1

I’m practicing my skills using copper, and find that I actually like
copper – I wish it didn’t have so many problems with oxidation. How
do people use it in finished pieces? In “The Complete Metalsmith” Tim
McCreight mentions lacquering or waxing copper patinas, but notes
the drawbacks of both. I think that lacquer would start peeling and
chipping off a flexible knitted or crocheted piece pretty quickly.

In “Textile Techniques in Metal,” Arline Fisch advises using coated
copper wire manufactured for the electronics industry for knitting
and crocheting with copper wire, and there are photos of gorgeous
pieces she has made incorporating the stuff in the book, and I found
some photos online:

http://www.mobilia-gallery.com/exhibits/fisch/fisch_arm.html (part of
a group exhibition:
http://www.oaklandmuseum.org/exhibit/exhi_fisch.html

I got a quote from a supplier on some natural-colored 30-gauge
copper wire coated with polyurethane and nylon at about $12
USD/pound. This price is reasonable, the problem is the 8-pound
minimum order, which is a lot since I don’t know if I’ll like working
with it. The coating abrades off craft wire too easily, and I don’t
want to work with extruded plastic-coated telephone wire. I also
wonder if working with the coated stuff is really good practice for
working with fine silver wire, which is what I want to do when I’ve
improved my skills.

So… If I make something that I really like while practicing with
bare copper wire, what could I do to make it usable?

Fran
Zemyna Designs
Swarthmore, Pennsylvania, USA


#2

Fran,

I use a lot of copper for the students to practice with at my
school. I use a lot of copper for my own sculptural pieces and some
jewelry. It is a wonderful metal within its limits. It is like all
other things. You have to learn its chacteristics…what it can and
can not do and work within those limitations. Any coating will
eventual come or wear off, including plating. The raw metal will turn
the skin funny colors. It will corrode in contact with dissimilar
metals. This is the nature of the beast.

If the piece is really experimental, I work out my ideas in copper
first then reproduce them in gold or silver.

Every metal has its characteristics and limits. The fun is in
learning how far you can go before hitting those limitations. The
key: learn the nature of your materials. I love seeing what I can get
away with once I know what I can’t get away with. Usually much more
than one thinks possible.

Bill Churlik
@Bill_Churlik
www.earthspeakarts.com


#3

Hiya Fran, I can’t speak for treating it, but I really love copper
as-is. It’s a living metal, and I just live with it. If I’m desperate
for it to look brand new again, I just swish it in some lemon
juice/water, but I generally don’t bother.

Kelly


#4

Fran,

You could try something that is used on bronze work, especially
sculpture - Butcher’s Bowling Alley Wax. You can get it in 1 lb. cans
for about $ 10.

Brian Corll
Vassar Jewelers
1002 East Simpson Street
Mechanicsburg, PA 17055


#5

Hi Fran,

If you are looking to protect your finished pieces, something I
learned right here on this very forum is to use car wax. I can vouch
it works great. It needs to be the paste wax. Clean your piece
thoroughly, and coat the cleaned piece with car wax. I wear gloves or
hold the piece in another cloth, and I apply the wax with a q-tip.
This way, you prevent any fingerprints or other residue from being
caught under the car wax and oxidizing. Let the wax dry, and then
buff it off.

Thanks to the forum members who taught me about it earlier this
year.

Miachelle


#6
So... If I make something that I really like while practicing with
bare copper wire, what could I do to make it usable? 

Fran, I agree with you that coated wire is not suitable (at least
not for what I want to make in copper, etc.). Lacquering and waxing
are good for things meant to hang on the wall. Copper can be oxidized
(chemically) and it also can be fire-oxidized for a reasonably
permanent finish. There’s been a lot of discussion on this in
previous e-mails; try the Orchid Archives.

All the best,
Judy Bjorkman


#7

Hi Fran,

I did the same thing when I started, and also found that I really
liked copper. It’s not a good color for me to wear myself, so I gave
it away and, eventually, sold it. I never coated it with anything
and, while it would darken some, nobody ever complained.

I have a vague memory of once trying to clean a piece that was going
into an art auction and having it turn gray, which I assume is
because I used a silver polishing cloth, so I never did that again. I
know that, on some people, it turns green, but that never happened
with any of my friends, or the customers I kept in contact with,
although I did warn people about the possibility. In my experience,
women who like copper jewelry are so excited to find someone who’s
making it that they aren’t worried about oxidation.

One tip–if you want to make earrings, try using anodized niobium
earwires. I always “cheated” and bought the ready-made blues, greens,
and purples from Reactive Metals–they look lovely with copper. Rio
also sells (or used to, I don’t have a current catalog) a strange
brown color which is almost a match for darkened copper. Unlike Joan
Dulla, an Orchidian whose work you must see,
http://www.joandulla.com/Crochet%20work%201.html I found manipulating
niobium wire to be an unpleasant experience, and I didn’t want to get
into anodizing.

Since I really wanted to play with color. I eventually used Artistic
Wire http://www.artisticwire.com/ in some pieces and I didn’t have
problems with it–maybe theirs is better quality than what you’ve
used, or maybe I was lucky. Their “Non Tarnish Brass” looked really
pretty in fine crochet and people assumed it was gold until I told
them.

As for working with fine silver, in my experience, it’s like working
with butter (if you buy what is sold as dead soft, anneal it anyway,
and you’ll really see what I mean). So, after copper, it will feel
really easy.

Lisa Orlando


#8
Any coating will eventual come or wear off, including plating. 

That’s what I thought…

The raw metal will turn the skin funny colors. It will corrode in
contact with dissimilar metals. This is the nature of the beast. 

Yes… not good for crocheted necklaces or bracelets… but maybe
longer-lasting when used for pendants or brooches?

Does it tend to corrode when in contact with “red brass” (90%
copper, 10% zinc) or lead-free pewter (92% tin, 7.5% antimony, 0.5%
copper)? (I’m sensitive to nickel, want to try using pewter as a
white base metal to practice on instead, found a manufacturer of
pewter sheet and wire 0.8 mm. [about 20-gauge] and thicker.)

I have a design idea for fabricating a pendant/pin that would
involve one sheet each of copper, brass, and pewter. I would pierce
different parts of a pattern into each of two of the sheets, then
rivet them to a base of the third sheet. I think this would give me
good practice piercing, sawing, filing, and finishing. Trying to
solder copper, brass, and pewter together sounds impractical, hence
the attempt to fabricate a cold connection. Not sure if riveting
three sheets together is a good way to start, maybe I should think
about cutting the base sheet to include tabs to fold up over the
other two, and work them into the design somehow. I don’t like to
copy other people’s projects, even for practicing, but sometimes end
up frustrated because my own design ideas don’t work out with the
materials I’ve chosen. I’m thinking that the pewter will be the
softest metal, so it should either be used for the middle layer,
where it will be most protected (if I use tabs), or maybe the bottom
layer, if I use rivets, so that any scratches that happen after the
piece leaves my hands will most likely be on the back of the piece.

If the piece is really experimental, I work out my ideas in copper
first then reproduce them in gold or silver. 

I am basically practicing with copper before working with silver
(hopefully gold will be somewhere in my future).

Every metal has its characteristics and limits. The fun is in
learning how far you can go before hitting those limitations. The
key: learn the nature of your materials. I love seeing what I can
get away with once I know what I can't get away with. Usually much
more than one thinks possible. 

I’m happy that you’re emphasizing that it can be fun! I am feeling
anxious, keep reminding myself that even base metal mistakes can be
sent back to the supplier for refining and re-use instead of tossed
into a landfill.

I was blown away by these photos of fold-forming that I found while
browsing:

http://brainpress.com/Foldforming.html

which seems to work beautifully in copper. Have you tried this
technique?

Fran
Zemyna Designs
Swarthmore, Pennsylvania, USA


#9
It needs to be the paste wax. Clean your piece thoroughly, and coat
the cleaned piece with car wax. I wear gloves or hold the piece in
another cloth 

Thank you, Miachelle. I wonder if I could manage this on pieces
knitted or crocheted with fine wire. Do you know how long the
treatment is likely to last?

Fran
Zemyna Designs
Swarthmore, Pennsylvania, USA


#10
I can't speak for treating it, but I really love copper
as-is. It's a living metal, and I just live with it. If I'm
desperate for it to look brand new again, I just swish it in some
lemon juice/water, but I generally don't bother. 

Thanks for the encouragement, Kelly! I think it looks beautiful. I
don’t like green skin, but am thinking about pendants and brooches?

Fran
Zemyna Designs


#11

I’ve been told it last a long time, but I haven’t used this enough
to tell you an accurate amount of time. I’ll find out soon enough-a
magazine has my copper piece that I used the car wax on, and the
piece isn’t scheduled for publication until March of 2007. So, by the
time I get it back, I’ll know how long it lasts!

Miachelle