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Cracking Gold


#1

There was an article seen recently of a Japanese process for
reducing the oxygen content in cast billets.

A non-ferric cylinder two and a half inches in diameter and
three inches tall with three hemicircles or arcs cut out
of the base so it looks like a tripod is constructed. Three
copper rings are also required. The sizes of the rings are 16 g
copper by a quarter of an inch high and a diameter as required
for the following.

Place three layers of white unbleached cotton six and a half
inches in diameter over the top of the tripod and use one
fabricated ring to push the cotton down into the tripod
actually called a “casting cradle”. Down is an inch or so. Gather
the cotton outside the cradle and and secure it to the sides of
the cradle with another sized ring. Place the fourth layer of
cotton over the casting cradle and secure it with the third
ring. Add a small smooth depression in this cotton disk with a
small smooth finger.

This unit is put into a non-ferric container about six inches in
diameter and six and a half inches high. Very hot water is added
to the container so it covers the casting cradle.

A quart of water is set to boil. The numbers are such that when
the extra quart of water is added to the container it will cover
the the casting cradle by two inches.

The metal is melted in a flask, and is poured onto the cotton
cradle JUST after the quart of boiling water is added to the
large container. The molten metal passes through the water
giving up the oxygen as it settles on the cotton cradle.

Now your going to ask if I have done this (as a test of my
metal) and the measure of success.

I used brass for the large container as on a lucky day I found a
piece of brass two feet by three feet of 16 g for three dollars
at a recycle place. I used industrial copper pipe two and a half
inches in diameter found in a metals scrap yard at two dollars a
pound. I cut the rings from the copper pipe also 16 g and added
material to two of them and reduced one in diameter.

I have made all of the parts described. I have melted metal and
poured through the water without an explosion. I have usually
missed getting all the metal onto the cotton cradle. The
produced ingot is kind of egg shaped but seems very dense. One
reward is the generation of interesting sounds.

Between adding the boiling water, holding the molten metal in
place, looking where to pour through the steaming water, and
keeping the torch in place too, it is a bit much for one person.

When next I try this, I will enlist another pair of hands. This
requires a little extra help.

The numbers given are from are from the kit I put together and
reflect the article.

The article is from an unpublished manuscript not mine.


#2
There was an article seen recently of a Japanese process for
reducing the oxygen content in cast billets. 

This makes me curious and have a question maybe Charles could
answer. I’ve been told I could take all those old silver buttons
and melt them fluxing alot and then pour into water making
one’s own casting grain of recycled metal. What effect if any
does pouring this recycled metal into water have on oxygen
content in the metal? Especially in sterling or 14kt gold? Dave

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Crystalguy Jewelry http://www.opendoor.com/stephensdesign/crystalguy.html
Recumbent Cyclist’s Advocacy Group
http://www.opendoor.com/stephensdesign/bent/rcag.html


#3

Last year I was priviledged to attend some workshop
presentations at the National Ornamental Metal Museum given by a
group of Japanese metal artists who spent several weeks at the
NOMM in conjuction with the gallery showing “Art Metal of
Japan”. The artiss included master Takuya Kosugi, of Tokyo
Gedai, and his students and associates Mitsuhiro Ishikawa,
Hirotoshi Ito, Kazuma Ohshita, Keiko Kubota and Ken-ichi
Suganuma. These were some really fine artists, in a very
different tradition than any of us here in Memphis had ever
experienced. They really treated us to some fabulous work.

They alloyed the gold-based metals used in mokume-gane as one
series of demonstrations. The process was quite similar to what
Mr. Eisenberg gives us below, but with some relatively minor, in
my eyes, differences, which may be due to the traditionalist
approach of these artists. Although I am a ‘newbie’ to this
whole subject, as well as to jewelry, I would like to comment on
these differences and similarities, with your indulgence.
Perhaps Mr. Eisenberg and/or others could comment on the two
approaches?

A non-ferric cylinder  two and a half inches in diameter and
three inches tall with three hemicircles <grin> or arcs cut out
of the base so it looks like a tripod is constructed. Three 
copper rings are also required.  

The frame work used by our traditional friends was made of
copper wire, or strips. I remember four legs, but there may
have been three. It was definately fabricated, and not cut from
a cylinder.

Place three layers of white unbleached cotton six and a half
inches in diameter over  the top of the tripod  and use one
fabricated ring to push the  cotton down into the tripod
actually called a "casting cradle". Down is an inch or so. <snip>
Place the fourth layer of cotton over the casting cradle <snip> 
Add a small smooth depression in this cotton disk 

There were two shapes of “cradle” used by Kosugi-san. One was
round, and the other somewhere between a rectangle and an oval!
Both were of the same relative scale as Mr Eisenberg mentions.
The round one was two-and-a-half or three inches in diameter, and
the rectangular/oval one a little narrower and a little longer.
I remember the fabric as a single layer of heavy cotton twill or
light weight canvas, sewn to the framework. The very slight
depression resulted in natural sagging of the cloth. I presume
the volume of the pour was guaged to the size of that
depression, as it did not overflow, but resulted in a somewhat
thin ingot.

            This unit is put into a non-ferric container about
six inches in   diameter and six and a half inches high.  Very
hot water is added  to the container so it covers the casting
cradle. A quart of water is set to boil.  The numbers are such
that when the extra quart of water is added to the container it
will cover the the casting cradle by two inches.

This part is quite different. A much larger container of water
was used. We used a galvanized wash tub, set up on bricks. A
propane “rosebud” about four inches in diameter was used to heat
the water to the point where it was just shy of painful to put
your hand in the water.

The metal is melted in a flask, and is  poured onto the cotton
cradle JUST after the quart of boiling water is added to the
large container.  The molten metal passes through the water
giving up the oxygen as it settles on the cotton cradle.

Pretty much the same, except that the flask we used was heated
in a charcoal fire! No additional water needed to be added to
the tub. The water in the wash tub was eight or ten inches
deep, so the gold was poured through five or six inches of
water.

Now your going to ask if I have done this (as a test of my
metal) and the measure of success.

I envy Mr Eisenberg! All I got to do was hand the cradle to
Kosugi -san, and to feel how hot the water was! BTW, Kosugi
contended, partially in jest, I am sure (hope?) that even in the
last century an outsider observing this might have been killed
to preserve the secrets of this process!

    I have usually missed getting all the metal onto the cotton
cradle.  

So did one of us ignorant Americans! Kosugi-san and group found
this hilarious!

The produced ingot is kind of egg shaped but seems very dense. 

Very dense, and very clean. Shiny from the moment we reached
into the steaming water to retrieve the still-hot ingot.
Although it seemed denser, the Japanese still took the ingot to
the hammer, thinning it down and squaring it up a bit to make
it denser.

One reward is the generation of interesting sounds.

Someone in the group watching the pouring remarked that the
squeals, moans, whistles and thumps sounded almost alive.

Between adding the boiling water, holding the molten metal in
place, looking where to pour through the steaming water, and
keeping the torch in place too, it is a bit much for one person.

The process was not quite this much of a juggling act to start
with. Since the water wasn’t as hot, there wasn’t as much steam
– until the metal was poured! Since we didn’t use a torch, we
didn’t have to juggle that. It was impressed on us that the
crucible must be taken from the fire, and gently, but quickly
poured into the cradle. An even, uninterrupted, undisturbed
stream was the goal.

    When next I try this, I will enlist another pair of hands.
 This requires a little extra help.

Even with a somewhat simplified pour right there at the end, it
wouldn’t hurt in the least to have help. The trouble at the
museum might be avoiding a crowd!

    The article is from an unpublished manuscript not mine.

Should the manuscript ever be published, or otherwise available,
I would really like to see it, as would, I am sure, several
other folks at the NOMM, and other metal artists from the
Memphis College of Art, etc., that really appreciated the work
of these fine Japanese artists. It is nice to see a variation
on this technique.

Thanks for letting me add my $0.02!

Marrin Fleet
@Marrin_and_Mary_Dell
Memphis, TN