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Keum boo burnishing marks


#1

Morning folks, After seeing a few orchid posts about Keum-boo a buddy
of mine, who had a .03 mm 24k sheet, and I decided to try the process
last week. What fun we had! After all the mystery around this
process we found it so simple and successful…er almost. I saw
Richard Mafong show someone how to do this years ago and but don’t
hardly remember a thing about the technique. The directions in the
book Metals Technique (and I believe Charles Lewton-Brain’s comments
on Keum-boo support this too) say that the resulting burnishing marks
may be removed from the surrounding silver by placing the finished
piece in hot pickle. Our experience is that this doesn’t remove the
burnishing marks nor does it restore the the frosty white finish to
the silver, which we like.

We were working in my friend’s studio so I don’t know how fresh her
pickle is. My buddy had the idea that pumis powder might be the thing
so I tried that (I have the finest grade pumis I believe, triple-F)
with some oil on a soft cloth and this dulled the gold so much that
its barely perceptible. I now suspect that multiple layers of the
.03mm are required to get a stronger gold appearance. As I remember,
Richard Mafong didn’t have any resulting burnishing marks. Did he
avoid this by not going past the edge of the gold? Hmm. Any ideas
anyone could give me for removing the burnishing marks and finishing
would be greatly appreciated.

Also Charles Lewton-brain wrote that pieces may be soldered and
formed AFTER kuem-booing. What are anyone’s thoughts/experience on
this? Is it best just to cold connect OR do all the fabrication
before-hand? Thanks in advance for your consideration. Bruce Raper


#2

I do quite a bit of keum boo, and have never had a problem with
burnishing marks. I use a well polished (very smooth burnisher),
and wonder if perhaps your burnisher may have a slightly rough spot
on it that could be cause leave marks on the gold. Alma


#3

Bruce, if the gold is as thin as what is called “leaf” then you
definitely need more than one layer. Eventually, the thin gold leaf
will look transparent and greenish as the silver “migrates” to the
surface. I’m not up on the chemistry here folks so don’t jump on me
for the way I’ve described this. One layer of leaf is also so thin
that it is very subject to abrasion so the pumice was not a good
idea. It’s best to simply stop at the edge of the gold. If you have a
tumbler with steel shot, this will polish the whole piece and not
damage the gold.

Marilyn Smith


#4

I don’t know to what millemeter my keum-boo gold translates to, but
I roll it out to about 36 ga., or about the thickness of heavy duty
aluminum foil. This is thicker than leaf, and it is generally quite
stiff from work hardening after rolling it. This works to an
advantage when cutting patterns with punches or knives, as it tends
to shear better.

Many people seem to think you have to apply a lot of pressure when
burnishing to get the gold to adhere. I’ve found if the metals are
perfectly clean and at the right temperature, adhesion is almost
immediate and no more than a light touch is necessary for adhesion. I
go past the gold edges, making sure I’ve pushed all the air out
between the two layers. I have no problems getting the gold to adhere
into the substrate patterns, and some are very intricate. After
completing the process, I pickle and then brass brush. This will
destroy the frosty finish you like, but I suspect you might be able
bring it back with an acid dip. Personally, I favor using patinas to
help provide contrast between the gold and silver, and I know some
who use the patina, then knock it back to where there is only the
very faintest line around the gold.

If you go to the Orchid gallery archives, you can see 3 pieces I’ve
done in keum-boo, 2 pr. earrings and a bracelet. Here’s the link:
http://www.ganoksin.com/orchid/palo.htm Even though the end effect
is not the same as what you want, you can see there are no burnishing
marks.

    Also Charles Lewton-brain wrote that pieces may be soldered
and formed AFTER kuem-booing. What are anyone's thoughts/experience
on this? Is it best just to cold connect OR do all the fabrication
before-hand? 

I do the decorative processes before keum-boo, such as reticulation,
etching or pattern rolling. While the pieces are still flat, I do the
keum-boo, because I use the low-temperature method using a thick
piece of metal as the heat transfer rather than a torch. After I do
the keum-boo, then I do any forming and soldering afterwards. In
particular notice the score-folded earrings in the shape of stylized
fan shapes. These were scored, folded, soldered and posts added.
after the keum-boo. If the keum-boo has adhered properly, it will not
lift.


#5

I have found that when I solder kum-boo’d pieces I develop problems
with blistering and failure of adhesion. Is there a good way to
avoid these problems?

Lee Einer


#6

Hi Bruce, Try the agate burnishers that Allcraft sells- get a pair
and switch them as they get too warm. They will leave less marks than
the steel burnishers. Jayne Redman introduced these to us in her
Keum-Boo Workshop here (which got rave reviews from all who
attended).

	Allcraft's contact info:
	135 West 29th St.
	New York, NY 10001
	(212)279-7077
	Ordering; (800) 645-712

I hope this helps!
Kate Wolf, Workshops at Wolf Designs, Portland, Maine
http://www.katewolfdesigns.com


#7

Bruce, I use a magnetic pin finisher for my production pieces to
remove burnishing marks. You can also use a soft felt stick with
rouge applied to the surface and rub out the marks by hand. Also
buffing with rouge on a soft buff on your flex shaft or polishing
lathe with light pressure is fine. Make sure all the edges of your
keum-boo are bonded properly or they might peel up. Pumice works
too. I used to use “Fine” before I got my magnetic finisher, which
left a soft satin finish. I then brass brushed with warm soapy water
to bring a higher sheen to the surface. Baking soda on a soft tooth
brush is a little more abrasive than a brass brush and works well
too. The finer the abrasive you use the less contrast you will get
between the gold and silver. You might play around with different
abrasives, scotch brite pads or steel wool for instance, until you
get the finish you’re looking for. I think Richard Mafong must have
burnished very carefully. I would rather have to deal with the
burnishing marks than risk not bonding the edges of the keum-boo
well.

After removing the burnishing marks, re-heat the piece slowly until
you get that frosty white finish back, then pickle. Chances are you
will get some bubbles - less if you heat really slowly. Just burnish
them back down (when the piece has cooled) with your fingernail or
something soft - I use a little burnisher I have made of delrin (any
soft plastic will do) - then pickle.

You shouldn’t need to add layers of gold in order for the gold to be
apparent, although you can achieve some wonderful color effects by
keum-booing then rolling out your piece and keum-booing again in an
overlapping pattern that allows the first layer of gold to show in
places. The rolled out pieces take on a greenish cast compared to
the thicker, freshly applied keum-boo. As an experiment, start with
a thick piece of silver, 12 or 14 ga., adding more keum-boo every
few rolls and burnishing down the bubbles as you anneal.

I make all of my production pieces flat to start, keum-boo, form,
and then solder if I have to. I try to use cold connections as much
as possible. Every time you re-heat you risk bubbling in the
keum-boo so it is better to solder first if you can. Oxygen can pass
through the gold if it is thin enough, causing less bubbling. Try
rolling your keum-boo material out to .02 mm - .01 mm.

Tevel at Allcraft, (800)645-7124, has ordered 24K foil in both .02
mm and .01 mm from Korea that should arrive any day. He also is
stocking agate burnishers from Germany that are the best burnishers
I’ve used for keum-boo. The gold doesn’t stick to the agate like it
would to steel. I use two, swapping off when one becomes too hot as
they can’t be quenched in water to cool them.

I too would love to hear from other people about their experiences
with this technique.

Regards,
Jayne Redman


#8
    I have found that when I solder kum-boo'd pieces I develop
problems with blistering and failure of adhesion. Is there a good
way to avoid these problems? 

I’ve found 2 things to result in failure of adhesion: lack of
depleted silver surface and less than spotlessly clean metal.

For the first one, to save time, anymore I just use fine silver to
begin with. The advantage, besides time and being completely certain
I have a fine silver surface, is that I can still mark the piece as
sterling after adding the gold. The fine silver is generally stiff
enough for most applications. If you insist on using sterling to
begin with, deplete the surface at least 5 times, and 7 times is
better.

The second is being scrupulous about the cleanliness of both metals.
I don’t use pumice, but instead use Ajax dishwashing liquid. This is
the plain stuff, not antibacterial or the stuff for automatic
dishwashers. It is extremely high in surfactants and strips off
residual oils, which is also important in etching. It does a job on
your hands too, and after you’ve washed both metals with it, you also
will not have any surface oil on your fingers or hands, so after your
session you’ll need some heavy duty lotion. Use a brass brush in
conjuction with the soap for highly textured silver, not necessary
for smooth metal, just be sure the water sheets off the metal. After
washing the metals and patting them dry, using really cheap paper
towels (nice paper towels have emollients in them which puts surface
oils back on the metal), wipe the metals down with alcohol swabs.

I don’t use the typical burnisher, but instead a dental wax modeling
tool that has a scooped spoon at one end and a rounded flat spatula
at the other, both ends highly polished. Polishing keeps them from
dragging. My two other tools are a basket weaving awl needle and a
darning needle, inserted into wooden dowel handles. These ones get
down into the bumpy surfaces of reticulated silver.

I think if you pay attention to these two things, you’ll find you
have much better success. The adhesion will be almost instantaneous
(I stick my metal on the plate, turn the fire on high and go do
something else for 20 min.), and you will not have problems with
blistering.


#9

Can’t resist joining this discussion . . . .

Kumboo is a wonderful technique. I have soldered findings both
before and after applying the gold foil. If blisters appear, I will
just go back to the kumboo burnishing process to reburnish the
blisters. If it is a large blister, you can pierce a pinhole and
burnish towards the hole. I prefer to go back to the heat method for
reburnishing, for durability, but on rare occasions will use a
fingernail if necessary for a stubborn spot. Sometimes, I think it
might be due to an impurity on the silver surface before applying the
kumboo - so, it is always good to make sure the silver is clean.

As Katherine described in her answer, my experience also has shown
that when the piece to receive the gold foil comes to the proper
temperature - the application (burnishing) of the foil is almost
effortless. And, I also continuously repolish my tools to have the
smoothest response to the burnishing. Of course, it is best to be
very careful not to marr the metal . . . prevention. I have modified
a few dental tools to use for burnishing. One of them has a small
rounded end that works well for burnishing very specific areas
(especially useful in reburnishing the few blisters that can appear
after soldering the findings). Be careful if your burnisher has a
pointed end that can cause havoc in marring the metal. Just sand
and refinish your burnisher and buff it to keep it smooth.

It is possible to use a small bristle brush (with bobbing compound
or equivalent) and/or possibly a small pumice wheel in the flex shaft

  • just to lightly clean any burnishing marks in the surrounding metal
    right up to the edge of the gold foil. Just go easy. Minimal
    careful polishing should be okay on the foil itself. If I’m
    achieving a soft matte finish - I will polish the piece first and
    then go back to do the matte finish.

Thanks for letting us know about the availability of agate
burnishers. . . I look forward to giving one (or, rather two) a try!

:slight_smile: Cynthia


#10

Dear Keum Boo artists, I have been doing Keum Boo for about 10 years.
I have no problems in applying Keum Boo either at the end or before
forming, constructing, fabricating etc. I have used Keum Boo on
raised silver pieces, hollow 2 inch cubes, spiculums, you name it.
The most important thing to do is to make sure that the gold sheet is
very very firmly fixed. You really can’t rush this procedure at the
beginning. The metal can then be formed in whatever way you want to.
It is a wonderful procedure and I am still hooked!!

Regarding burnishing marks make sure that by your burnishers are
kept highly polished. If you want to bring up the fine silver, or a
frosted finish, just heat and pickle about 3-5 times. This will soon
tell if your gold is properly adhered too, because little bubbles
might appear at this stage. Pressing them down sometimes work,
otherwise a tiny needle prick might help, but again it is best to
fuse the gold to the silver properly in the first place…

I use commercial grade alum. a handful to about one pint of water,
used hot, for my pickle. It is much safer than acids, and works a
treat in bringing up that frosted surface. best wishes and enjoy,
felicity in sunny West Oz.


#11
       when the piece to receive the gold foil comes to the proper
temperature - the application (burnishing) of the foil is almost
effortless. 

How do you determine the proper temperature?
–Noel


#12

Hi Gang,

  After washing the metals and patting them dry, using really cheap
paper towels (nice paper towels have emollients in them which puts
surface oils back on the metal), wipe the metals down with alcohol
swabs. 

In addition to Katherine’s paper towel suggestion I’d like to offer
the following idea.

If you’re looking for a good lint/fuzz free wipe, try one of the
paper filters used in many coffee makers. They’re inexpensive, lint
free & available all over.

Dave


#13
 How do you determine the proper temperature? 

Hi Noel - Okay, I’ll give it a try here to explain what works for
me! It was really trial and error to figure it out.

Thanks to some great feedback from Katherine quite a while back, I
placed a piece of flat steel on my hot plate as a surface for holding
the pieces (as opposed to placing them on the hot plate directly).
The piece of scrap steel sheet that I found is about 3" square -
12gauge thick. It works just fine. It even had a hole in it that
works well when there is an earring post.

I’ll just leave the pieces on the hotplate for a while and go do
something else and then, come back. I have marked a dot on my hot
plate where to turn the temperature dial each time - for the heat
that has worked for me. The piece will then be held at that
temperature. I’ll sprinkle a few drops of water on the piece and
when it sizzles it’s a good temperature to start the burnishing.

In a workshop with Komelia a few years back, I had prematurely tried
to burnish a piece of gold foil to the prepared silver surface. It
got very stiff and curled . . . work-hardened. So, she had me put
the piece of gold foil directly on the burner to anneal it. It got
nicely limp again - and was ready to reapply. Oh, by the way,
Komelia cautioned us not to use the old coiled type of hotplate -
because it can short when using the metal burnisher.

Komelia taught us to place the gold foil pieces with the watery gum
tragacanth mixture on the silver and then bring them all up to heat
together. I don’t always follow that rule - but will sometimes just
put the next piece to kumboo on the hot hotplate. What can happen,
then, is the pieces of foil might have a tendancy to dance and lift
up. If you are using a watery gum tragacanth mixture to adhere the
foil in place, it will change color - turns black and then
disappears. That is another clue of a good time to burnish.

I don’t necessarily use the gum tragacanth solution - and have
started just applying the foil directly. I will just carefully place
the gold where I want it, tack it down here and there with the dental
burnisher and then burnish the whole piece down. When the tacking
adheres nicely, then it pretty well follows that the rest of the foil
piece is ready to be burnished. When tacking, it helps to hold the
burnishing tool steady and just rock it back and forth.

Hope this input made sense and is useful to your efforts. It’ll be
good to hear what works for others as well.

Cynthia :slight_smile:


#14

Cynthia, I too took a workshop with Komelia and we were using the
coil type of hot plate. This is what I use at home as well. What do
you exactly mean by short? What type of hot plate are you using?

I look forward to your answer,

Marguerite
@guerite57


#15

Hello all - Thanks to all of you here on the list I have successfully
added Keum-boo to my repertoire this year. I am using a hot plate
that is marketed to chemists and biologists so it has a flat
matte-finished top. It also has a temperature dial.

I set the hot plate to high and let it warm up. (It’s faster this
way). I fiddle with the dial to see where the indicator light will
goes out. When it goes out at about 650 degrees Farenheight, I
place the flat silver piece on the hot plate and add the gold foil.
I wait several minutes, tack the foil and then burnish. If the piece
isn’t hot enough, the foil won’t tack, so I just wait longer. I
solder on heads, findings, etc. and/or form after doing the Keum-boo.
I do get little bubbles that I burnish out.

I have a funny agate burnisher that I made myself. It is a wedge
shaped piece of an agate. It looks like a section of orange. The
outside (“rind” in the orange example) is highly polished. I can
hold the burnisher in a gloved hand (to resist heat) and use the
point for fine work and the middle for broad burnishing. It works
pretty well for me.

Finally I patina with Lime-sulfur spray (thank you John Burgess),
and coat with clear engine enamel (thank you Charles Lewton-Brain)
and set stones, etc. I really like this technique and I must thank
Charles Lewton-Brain for his wonderful description in the “Tips” plus
all of you for your invaluable advice.

Debby Hoffmaster


#16
  How do you determine the proper temperature? 

Another way of telling when the piece of steel on your hot plate is
hot enough is to scrape it with the burnisher, and when the scratch
shows a bluish color, that’s the heat you want.

Hint is courtesy of a class I took with Marilyn Nicholson, in Taos,
NM.

Ivy in Oakland


#17
 I am using a hot plate that is marketed to chemists and biologists
so it has a flat matte-finished top.  It also has a temperature
dial. 

Debra, I would love to know the source for that hot plate. When I
keum-boo 18K I have to be very careful not to heat the piece up so
high that I create oxides. I have a low wattage hot plate that I use
just for 18K but I can’t control the temperature perfectly with it.

Thanks to all of you who have been sending in keum-boo posts. As a
friend of mine said recently, being a creative person also means
being an inventer. With all the trial and error learning that goes
on in our field it’s wonderful to be able to eliminate some of it by
sharing our experimentation. It leaves us with more time to create!

Regards, Jayne Redman


#18

Hi Marguerite - Sorry to be slow in responding here. I was busy
getting ready for an event and the computer fell by the wayside! :slight_smile:
I also use the good old Toastmaster flat coil type of hotplate that
go on sale sometimes. They are really cheap. I’d love to get a hold
of one like Debra’s - the chemist’s one.

The hotplate Komelia mentioned as having a problem was a really old
fashioned one. I think the coils are actually coils of wire that
are then shaped in the current hotplate design. I have a vague
memory of what she was describing - it is different than the current
ones available - so, your’s is fine, I’m sure. Just thought, I’d
better pass on the caution - in case someone is picking one up at a
garage sale or ebay or has one in their attic.

By short, I think she meant that there will be a reaction to the
steel tool touching the burner and causing the machine to croak.
(Not a very scientific description!) Anyhow, sorry to make you
nervous - I’m sure your’s is fine.

Aloha,
Cynthia


#19

Jane I saw your post reguarding hotplates, I do not know what type
of hotplate most are using. I recently bought a Corning Lab type
hotplate that has a solid ceramic top. I bought it and a Wild (made
in Switzerland) Microscope for engraving and stonesetting. I am very
satisified with both. I bought on E-Bay from WR technoligies. A
search of microscopes or hotplates should turn up his items. I am not
connected in any way, just a satisified customer.


#20

Jayne Try Fisher Scientific. You want an aluminum top hotplate (not
ceramic). It must go to at least 700 degrees F.

Try this link. search hotplate, then choose aluminum top.

https://www1.fishersci.com/catalogs/root.jsp;jsessionid=173%3A3dcf9d3
5%3Adf9 2f77266a501d?catalogParamId=839806&catalogParamType=R

Debby