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Kuem boo Question


#1

Hello All, I understand that in kuem boo it is important to have
contact between the silver base and the gold foil. In the case of a
highly textured base, such as reticulated silver, could one
carefully impress the gold into the texture while cold? I’m aware of
the burnishing requirement but how is that achieved with texture?

Also, aren’t we basically creating a eutectic bond? Do we use a
carbon based solution to help this along as in grannulation?

Thank you in Advance, Orchid Rules! Karla in overcast So. California


#2

Read this article published here at the Ganoksin project:

It is not a eutectic bond, more like velcro or a very intimate
atomic attraction. The temperatures are not high enough to permit
alloying or diffusion to any great extent.

best
Charles

Charles Lewton-Brain/Brain Press
Box 1624, Ste M, Calgary, Alberta, T2P 2L7, Canada
Tel: 403-263-3955 Fax: 403-283-9053 Email: @Charles_Lewton-Brai1


#3

Karla, Please refer to the extensive thread in Orchid archives on
Kum-boo. Just a few pointers. You need heat in order for kum-boo to
work. Kum-boo works well on reticulated surfaces. You just need to
burnish the gold well into the crevasses. Good luck, Marguerite


#4
 how is that achieved with texture? -- 

Karla,

The Kum-boo process is the same with smooth or textured metal. It’s
amazing to watch the gold foil just fall right into whatever texture
the underlying silver has. I did a piece of foil onto silver sheet
roller-embossed with a fine screen texture. The gold took on the
texture perfectly with only light burnishing. It just seemed to
"relax" right into the crevasses. I’m sure you could do it with a
reticulated surface. Some radical crevasses might take a little more
work, and I’m sure you can find an instance where it might not work,
but give it a try. By the way, Karla, if you’re in Southern
California, you should look into joining the Metal Arts Society of
Southern California (http://www.massconline.com/). Kum-boo master
Komelia Okim recently gave a two-day workshop (which I attended).

Bill Gallagher
www.billgallagher.net


#5
    It is not a eutectic bond, more like velcro or a very intimate
atomic attraction. The temperatures are not high enough to permit
alloying or diffusion to any great extent. 

Hi Charles, I had a phone discussion with a metallurgist the last
time this came up on Orchid. We are both of the opinion that Keum boo
is a type of diffusion bond. While the temperature is very low
compared to mokume type bonding the weld is assisted by the pressure
of the burnishing which because of its small contact area is very
high. It is the combination of the heat and pressure that set up the
diffusion bond. Diffusion happens at any temperature above absolute
zero if the faying surfaces (the surfaces to be bonded) are clean,
free of oxides and in intimate contact. You can substitute
temperature or pressure to shorten the time needed to bond the
surfaces.

Jim


#6
       It is not a eutectic bond, more like velcro or a very
intimate atomic attraction. The temperatures are not high enough to
permit alloying or diffusion to any great extent. > ....We are both
of the opinion that Keum boo is a type of diffusion bond.... 
Diffusion happens at any temperature above absolute zero if the
faying surfaces (the surfaces to be bonded) are clean, free of
oxides and in intimate contact. 

G’day; As a matter of interest, has anyone heard of ‘Jo blocks’?
(Johannisburg Blocks?) These are blocks of pure quartz in certain
thicknesses and the surfaces are ground flat to within a few
wavelengths of light. They are used only by high precision
toolmakers and scientists in a temperature controlled, micro air
filtered room and the engineers wear special overalls. In use they
are “wrung” (slid together with a circular motion) one upon the
other to build up a very precise height above a perfectly flate
plate. Gloves when handling jo blocks are essential Because they are
so perfectly flat, once ‘wrung’ together, two blocks are very
difficult to pull apart: They have to be wrung apart. 50 years ago
when I worked in a research station, the chief toolmaker swore loud
and long because when he needed to use the set of jo blocks, the last
person to use them (NOT one of the precision toolmakers!) had left
two blocks wrung together and their atoms and molecules had diffused
into each other so they could not be separated - and this happened at
20C. and normal pressureover a few months. Thus this very valuable
set was thus rendered virtually useless. An extreme example of
molecular diffusion.

Cheers, John Burgess @John_Burgess2