Kum-Boo Workshop

Jewelry Discussion
21

Nina,

The gold foil sold by Enamelworks Supply Co. is much thinner
than the Kum-boo gold foil from Korea. I have used both of these
foils successfully though I did find the thicker Korean foil
easier to attach. On the rings and beads that I made using the
thinner foil (purchased from Enamel Emporium in Texas
713-984-0552) I found that I needed to apply several layers. The
thinner foil is more easily absorbed into the silver which can
result in some interesting green gold shading.

Coral at Enamelworks Supply is very knowledgeable about
everything that she sells and always willing to share her
freely. Especially in regards to enamels and etching
using the PNP photoresist. Don’t know if she can tell you much
about the Kum-boo process. Maybe.

Have you done Kum-boo with the thinner foil from Coral?

I am interested in hearing about your source for the sinusoidial
stakes. Does this supplier also sell Delrin or nylon hammers for
this technique?

Carol Holaday

22

Thanks Peter for the info. My foil piece was not subjected to
additional head but then again it was only 2 years old so I
haven’t begun to see the migration. However, in the interest of
"Quality", this will prevent me from using the leaf
again and stick to foil.

23 
I usually melt the palladium first and add the gold in that
case, since the palladium melts at a slightly higher temp.

I’ve applied 24K gold leaf over palladium leaf on glass, doing
lampworking. It yields a very interesting color, and it never
occurred to me that you could actually work with an alloy of the
two. When you alloy it for kum boo, what are your proportions?
What is the form in which you purchase the palladium to do this?
Casting grain? In the Hoover and Strong catalogue I see palladium
as alloyed with ruthenium. Do you use this or pure palladium? Is
there some other source for palladium you prefer? And palladium
melts at such a high temperature - would I need an oxy-acetylene
torch to do this?

Thanks,
Rene Roberts

24

Yes, hold the copper over a busy flame and deposit alot of
carbon on it. so it turns black… The gold won’t adhere to it.

You don’t need to worry about the gold sticking to your rolling
mill

unless you keep it at about 900 degrees:>)- I make my own gold
… and roll it until the rollers are together… and then pass the
gold thru a few more times - it seems to stretch even after
reaching that pressure… and then I put it between two sheets of
paper and continue to roll it with be rollers together.

I had an experience of buying an ingot from a coin store that
they told me was 24 K… It wouldn’t work… it was 22 I guess,
so I had to call the refiner… and get some… So now I have this
22 K …:>( but after reading Dr. Dule’s note… I will try
again. I thought you could only Kum-boo 24K gold.

Joan

25

Carol, I roll my own gold thru the "upper arm workout’’ mill and
have great success and nice arms too! I take a piece of 24kt 30g
sheet about 1x1 and roll anneal roll and anneal for a LONG time
til I get the desired thinness. I have never had the sheet stick
to the rollers, but, I have had the piece tear slightly but this
is salvageable. When the sheet gets real close to the desired
thinness I very carefully anneal still using the torch. I
haven’t tried heating up a copper sheet or pan to anneal the
gold. So, this method takes about 3 hoursor longer to do and the
rollers are touching or beyond touching: your arms look great and
your breathing heavy, but isn’t that half the FUN! You get ALOT
of kum-boo gold from a 1x1 sheet of 30g gold. I would love to
learn more about using different karats of gold and using
different metals besides silver to accept the gold. Would a
kum-boo expert please step forth and show us the way! Lisa

26

Dear Nina,

Although I live in Wisconsin, I just finished an excellent
workshop in Mesa, Arizona sponsored by the Arizona Designer
Craftsmen… I met an incredibly wonderful person Joan Dulla
who organizes the metal and other media workshops in both Mesa
and Tuscon… I’m sure she has the scoop on just about everything
in Arizona as far as metal goes. Her e mail address is
Joan963@home.com If you have problems finding her she can
also be contacted through the Mesa Gallery in Mesa Arizona.
Good luck! Julie

27

Hi all - Well, had a wonderful 3 days - it is always great to
experience new techniques. Komelia Okim has Hawai`i roots - so,
perhaps she will come again. She demonstrated the kum-boo on
smaller work - helped us with our pieces - and showed us the
application on one of her raised forms - an elegant creamer with
a spiculum handle.

She showed several slides - and there are many variations of
results depending on source of gold foil and thickness. She
mentioned that the gold foil from Thompsons is 22k - not 24k and
is thinner. It will still work - just takes a few layers - as
has been discussed. Her gold foil is about the thickness of
tracing paper. I would think that one of the major advantages
with this thickness is that is is easier to handle. Still it is
a very delicate medium. She mentioned that it took a week to roll
out 24k foil in a demo - so, I signed off on bringing in my piece
of gold. Wanted to focus on the kum-boo itself.

Am glad to see there is a lively discussion on the variables for
this technique. Must get back to the studio. cynthia

28

My source for the synosodial stake is a personal friend who
occassionally makes jewelry tools in his spare time (he’s retired
and soooo busy). He did not make the hammer or other tools for
anti-clastic work. I bought a nylon hammer from Rio or Indian
Jewelers Supply and cut it with my ban saw then smoothed the
sides out with a sanding machine. In you want me to contact my
friend to see if he has stakes available or is willing to make
one, I am more than willing to do so. He would feel awkward if
someone else contacted him (he very shy.) Also, what is your
source for Korean foil??

29

Hello all:

I’ve been seeing the thread concerning kum-boo and am curious.
I understand the method of mixing gold & silver or plat. and gold
and then rolling it into thin sheets but exactly what do you do
with then? I realize that you can’t truly learn a technique this
way but I would like a description. Anyone out there who is
proficient at it care to expain it to me? Just a simple outline
of the process would be most appreciated.

Best;
Steve

30

There is info on Keum-boo (or kum-bu) on Ganoksin at:

Charles Lewton-Brain
Box 1624, Ste M, Calgary, Alberta, T2P 2L7, Canada

31 
 Sounds as if you do a lot of kum-boo foil making. Would you
please share your techniques for rolling the metal to the
proper gauge? Do you use an electric mill? Do you roll the gold
between sheets of something else? Etc..? Having a variety of
colors to work with sounds interesting. Is there a Webb site to
view your work?

My apologies to you and others who have had some questions on
this subject of KumBoo which I had posted awhile back. Some
family problems have kept me occupied. But I’ll try to cover, as
best I can, some of the questions. However I am not an expert by
any means, and since learning the technique, and exploring the
directions given by the expert in this field, Prof. Komelia
Okim, I tried to push the envelope, in an effort to satisfy my
inquisitive nature.

I reasoned that if I could affect a “bond” between fine silver
and fine gold at a fairly low temperature obtainable with an
electric hotplate (@600 F), might I not also bond an alloy of
gold and silver(no Cu) to fine silver? If I did that, I would
have an applique of white gold which would not be affected by a
liver dip and have more than one color for contrast to a silver
background. I made a small ingot of 50/50 Au to Ag, milled it
down to @38G foil and attached a design(geometric) to SS base,
which had a fine silver layer using the same procedure taught to
me and it worked just fine!

From that initial success, I made other alloys, such as an18K
green gold, and others too. This is getting rather lengthy, and
I’m sure each of you can get the general idea. For the palladium
alloy I used 75% AU, 20% PA, and 05%Ag for a nice workable alloy
with the yellow bleached out.

The thickness I roll the metal to is 36g to 42g, and it goes
very fast even in a non motorized mill. Mill the ingot until the
rollers touch, make 2-3 more passes at this setting, and then I
use a sandwich of tracing paper and the metal to bring the
thickness down to gauge I want. Too thick and burnishing becomes
difficult to effect the intimacy of contact necessary for
bonding.

When metal becomes work hardened I anneal by placing the gold on
a sheet of steel @18-20g and heating from underneath with the
torch until steel turns red and this will anneal the gold
without risking melting.

For Rene Roberts

H&S suppied the palladium in sheet form

For Joan Dulla

I believe the 22K gold you tried had copper as part of the

alloy and I think this is what interferred with the bonding.

For Lisa

I don't know the answer to bonding to other metals, but I do

know that when using a steel burnishing tool, if it gets too
hot, the gold will stick to it and when rolling out the gold if
you use a sheet of clean copper to get the gold thinner in the
mill, the gold can stick to the copper sheet. (I guess cold
fusion)

I hope this has been helpful. Please feel free to e-mail direct
for further clarification.

JZD

32

I enjoy using Kum-boo in my pieces, however I would love a
better glove than the cotton ones. I use a strong electric hot
plate and I hold my piece with a second burnisher. Pauline

33

Proportions 75% Gold, 20% Palladium,5% Silver-also 50/50 gold
and palladium I use pure palladium from H&S Yes an oxy-acetylene
torch is necessary PA --MP is 1550 Centigrade, Au-1063C

Hope this helps JZD

34

Dear Steve and Carol; you may have already received the
you requested, but since the technic is new to you,
an additional explanation might be helpful. The Kum Boo
procedure (also spelled Keum Boo) is one that permits the
application of fine gold as a final step in the enhancement of
an already constructed or cast piece of sterling silver. This,
to my knowledge, was originated in Korea, and the primary
proponent is Prof. Komelia Okim, a wonderful teacher and great
cook!

Basically a fine silver surface is raised on the S/S object by
repeated heating the piece without any flux, and then pickling
it to remove the copper oxides formed during the heating
process. The application of the gold in the form of very thin
foil -@40-42 gauge takes place at relatively low heat without
resorting to a solder. This is accomplished using an electric
hot-plate although a torch may also be used where larger pieces
are involved.

The explanation I’ve given myself, which may or not be accurate
(CLB has a different view of this) is that at the increased
temperature the molecules of both silver and gold are given
increased activity and by developing an intimacy of contact of
the two surfaces an exchange of molecules between the two metals
takes place, resulting in a bond. This contact is accomplished
by the burnishing, while the piece is on the hot-plate.

That basically is the technic, but as with most processes some
variations creep in to permit alterations and enhancement.

Hope this has been of some help JZD

35

Dear JZD:

While I did recieve a good description of the process, yours
contained some other bits that are useful as well. It sounds
like a very interesting method of embellishment that I’ll attempt
as soon as I can. I do have one question though, is the foil to
be left bright or would it be better to give it a light sandblast
finish to dull it and make the different colors of the metals
show better, Something like mokume’ gane’? I’m sure there’ll be
other questions as I attempt it and appreciate all the help.

Best Wishes;

Steve

36 
  I do have one question though, is the foil to be left bright
or would it be better to give it a light sandblast finish to
dull it and make the different colors of the metals show
better, Something like mokume' gane'?

If you are embellishing with 24K the contrast in color with
silver shows well whether shiny or dull, so I, personally would
not sandblast it. Also any particle, sand or other material, if
it got on the underside of the applique would interfer with the
“bond”. But if I use any other alloy, I prefer to color
(“oxidize”) the base metal to obtain a good contrast.

Hope this helps, JZD

37

I do have one question though, is the foil to
be left bright or would it be better to give it a light sandblast
finish to dull it and make the different colors of the metals
show better, Something like mokume’ gane’?

Jumping in un-asked: The foil is thin enough that further
finishing is not recommended (per John Cogswell). The
depletion-gilded silver, especially if it had been
roller-textured, provides a good contrast to the 24 K. In order
to compact the fine silver surface as it is brought up, try light
brass-brushing after each heating. This should make the layers
more durable. At the end, you might prefer the “frosted”
appearance as a backdrop to the gold foil, rather than burnishing
that last time. Both effects seemed to provide good contrast.

Pam’s 2 cents worth.

38

Pam:

Thanks for your contribution. It’s certainly worth more than
two cents! Please don’t feel shy about jumping in with your help
or asking questions. That’s what Orchid is all about.

Best Wishes;
Steve

39

JZD:

Exactly what do you mean by oxidizing the “base metal?” Are you
refering to the host piece on which the Kum-boo is applied or
one of the metals within the foil itself? Your reply is most
appreciated.

Steve

40

Hello again Steve: Sorry to be so ambiguous, yes I did mean the
host piece. I used the term “oxidize” which is common usage when
one applies liver of sulphur to color silver, but it really is
not oxidizing the silver. Joe (aka JZD)