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Keum-boo on Copper


#1

Has anyone had experience with 24K gold keum-boo on copper ? Are the
temperatures needed for fusion the same as for fine silver ? I have
a hankering to do some large domed (or “pocketbook”) pendants in
patinaed (is that a word) copper with 24K gold foil and some other
things.

What solder would you use to join copper domes ?

Brian Corll
Vassar Jewelers


#2

Hi, Brian,

Be sure to let us know if you succeed in fusing the gold foil onto
copper! As far as I am aware, the oxide layer that copper so rapidly
produces keeps the process from working (same reason you use fine
silver rather than sterling) but I’d be delighted to be wrong.

As to solder, I am not aware of anything that really matches. Indian
Jewelry Supply has a solder caller #7, or fosflow #7 or some such,
pretty low-melting, that seems to take on the color of copper or
brass to a degree. I have tried using pre-1967 pennies as copper
solder as has been suggested from time to time, but didn’t have much
success with it. Some people solder with silver solder, then
copper-plate over it.

Good luck!
Noel


#3
Some people solder with silver solder, then copper-plate over it. 

Also pickle contaminated with steel with flash your silver with a
copper coating… usually just put a bolt into the pot for a while
until nice and blue and leave it in there till done.

K. David Woolley


#4

Noel,

Be sure to let us know if you succeed in fusing the gold foil onto
copper! As far as I am aware, the oxide layer that copper so
rapidly 

Actually, I have read that the keum-boo technique works on gold,
silver AND copper. No explanation as to how though. If worse comes to
worse, I can use some Klyr-Fire to attach the keum-boo and then fire
a clear flux over it. Building layers of transparent enamels on top
of that add many interesting possibilities.

Santa Fe Jewelers Supply has a copper solder. I’ll give it a swing
when it gets here.

Brian Corll
Vassar Jewelers


#5

Dear Brian-

Use hard silver solder to join the copper domes. To hide the solder
seams, submerge the piece in contaminated pickle to copper plate it.
Steel adds an electrical charge to used pickle and turns it into a
copper plating solution. If the piece is a hollow form with a small
hole, neutralize the piece and use a syringe and thoroughly rinse
inside to remove the baking soda.

Regarding Keum-boo on copper, the oxides that form on the surface of
the copper when it is heated inhibit the diffusion bond, the
permanent bond between the thin layer of gold and the copper below. I
am not an expert on bonding gold to copper. However, in my
experimentation, I have successfully bonded gold to copper, but I
have also had mixed results. I imagine it is possible to develop a
method for more predictable results. The important factor seems to be
getting the piece up to the bonding temperature quickly so the oxides
have less time to form.

Apply the patina after the Keum-boo is complete.

For more on the Keum-boo technique with gold foil on
sterling, check out my upcoming DVD series, Keum-boo Basics, The Art
of Bonding Gold to Silver, vol 1: Dangle Earrings and Keum-boo:
Beyond the Basics, Bonding Gold to a Hollow Form, vol 2: Hollow
Pendant. The series will be released this fall and will be available
through Rio Grande, AllCraft, Revere Academy and from me directly.

Christine Dhein
Assistant Director


Revere Academy of Jewelry Arts
760 Market Street, Suite 900
San Francisco, CA 94102
phone: 415-391-4179
fax: 415-391-7570


#6

I don’t know how you intend to use the copper solder, but it will
not hold up under enameling temperatures. It is similar to the solder
plumbers use for copper pipes.

As an enameler who went the self-taught method and THEN took some
classes, I would suggest taking at least a basic enameling class, as
there is no reason to re-invent the wheel as I did. Enameling, like
goldsmithing, is a hands-on, visual process that is faster to learn
by observing a knowledgeable person doing the work.

Speaking from experience,
Alana Clearlake


#7

Alana,

If I used the copper solder, I would not enamel afterwards. I would
use it only to join domes before or after applying keum-boo by
whatever method. I’ll try the whole thing this weekend (probably
tomorrow) and let you know what the results are. Never quit 'til it
works !

Brian Corll
Vassar Jewelers


#8

Thanks, Christine. I have a number of ideas I want to try out until
I come up with the one that works. I just like the idea of 24K gold
against copper. The similarity yet contrast in colors between the two
metals could create some very striking pieces.

Brian Corll
Vassar Jewelers


#9
I don't know how you intend to use the copper solder, but it will
not hold up under enameling temperatures. It is similar to the
solder plumbers use for copper pipes. 

It depends on the type of solder. There is a type of copper solder
that is available as either a copper, phosphorous or copper, silver,
phosphorous mix that melts up near the melting point of copper
(1800-1900 F) while this is way above the melting point of the
enamel I don’t know what reaction the enamel would have with the
phosphorous content. But would be worth a try at least once to see.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#10

Thanks, James. Santa Fe doesn’t say anything about the melting temp.
of the copper solder. I’ll have to inquire. But what you suggest is
what I was expecting.

Brian Corll
Vassar Jewelers


#11

Thanks for the I got my copper solder from Rio Grande,
and didn’t know that there is a harder one available.

Alana Clearlake