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Facilitating the fusing of high karet gold


#1

There have been suggestions about the use of copper carbonate as a
means of facilitating the fusing of high karet gold. I have some
copper sulfate on hand and wonder if this would work? Thanks- Alma


#2
There have  been suggestions about the use of copper carbonate as a
means of  facilitating the fusing of high karet  gold.  I have some
copper sulfate on hand and wonder if this would work?  

G’day; I doubt it. However, you could simply add a strong solution
of copper sulphate to a solution of sodium carbonate (washing soda)
and you will get a green precipitate of copper carbonate. Shake it
well, allow to settle and filter off the copper compound, using a
coffee filter. Dry it and voila: copper carbonate fusing compound!
Cheers,

John Burgess; @John_Burgess2 of Mapua Nelson NZ


#3

To those who are interested in fusing high carat gold , I have found
that using a copper cup with some salt solution in it and letting
that sit for a while creates a copper compound that aids in the
fusing process. I have also tried some filings of malachite in some
green flux and that sometimes helps, and to give Jean Stark credit I
have sometimes use her method of copperplaing the metal that I want
to fuse.The other thing that I find very helpful is to make sure that
the metals you are trying to fuse are clean and completly in contact.

Teddy {theaskay@aol.com}
Teddy


#4

the copper will give the gold something it fuses to easily. the
carbon helps prevent oxidation. Another method ( asuming you are not
trying to fuse sheets together): take some old pickle (very green
with cupric oxide), place the gold in the pickle and a pices of steel
or iron. the iron will be absorbed by the acid and the copper will
leave the acid (similar to the reaction in a battery). the copper
leaving the acid will plate itself onto gold or silver in the pickle.
then use flux to absorb the oxygen during fusing. after fusing, put
it in pickle (without steel or iron) to remove the copper. I am not
saying this method is better, simply another option.


#5

Michael, I am still wondering of the bath in steel contaminated pickle
will also aid the fusing of silver. Has anyone tried that?
Teresa


#6
the copper will give the gold something it fuses to easily.  

G’day Here is a farden’s worth; The gold doesn’t actually fuse to
the copper; the copper alloys with the gold at the point of contact
and that alloy has a lower melting point than the gold. Thus adding
a few microns of copper to the workpiece is simpler and ‘cleaner’ than
using solder. Standard granulation process used for thousands of
years. (only the ancients used malachite to provide the copper) The
thin layer of copper will of course oxidize to black cupric oxide in
the flame, but will vanish when placed in pickle for a minute or two.

Sometimes one makes a pierced design on a gold ring strip, then
solders it to a thin plain strip, bends it into a perfect circle and
solders the ends together. One method of enhancing the pierced
design on such a ring is to copper plate the job, and either
deliberately oxidize it, then abrade and polish off the outer surface
leaving the pierced parts black copper oxide, or to use potassium (or
calcium) polysulphide [liver of sulphur]; these liquids won’t blacken
high carat gold) to do the blackening, or, far superior, use niello
to fill the pierced parts. There is even the possibility of using a
variously pigmented high quality epoxy resin to enhance the pierced
parts. Take it from there…

Cheers,
John Burgess; @John_Burgess2 of Mapua Nelson NZ


#7

Teresa,

It will work for fine silver but not sterling as there is already
too much copper in the sterling .

Jim


jbin@well.com
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601
510-533-5108


#8
     One method of enhancing the pierced design on such a ring is to
copper plate the job, and either deliberately oxidize it, then
abrade and polish off the outer surface leaving the pierced parts
black copper oxide, or to use potassium (or calcium) polysulphide
[liver of sulphur]; these liquids won't blacken high carat gold) to
do the blackening 

How “durable” is the oxidation created this way? I realize it’s
pretty well sheltered within the pierced sections, but does it stand
up well under exposure to, say, dish soap and other household
cleaning products encountered under normal use, or do you need to
refresh the oxidation periodically?

Warm Regards,
Shawn


#9
How "durable" is the oxidation created this way? 

G’day; not very durable. It would fade in a month or two of cleaning
with a toothbrush and ‘Silvo’ - which those very few who do regular
cleaning seem to favour - and pickle would ‘fix’ it in a few minutes.
A better way is to use Niello, a compound of silver, copper, lead and
sulphur which melts at around 350C is extremely durable and has been
used for centuries. But try and talk someone else into making it
for you! Cheers,

John Burgess; @John_Burgess2 of Mapua Nelson NZ


#10
   Michael, I am still wondering of the bath in steel contaminated
pickle will also aid the fusing of silver. Has anyone tried that?
Teresa 

Of course. all you’re describing here is the standard method often
used for granulation, both of gold and silver. There are several
methods involved, but pretty much all of them need to introduce copper
to the surface of the granules, to lower their melting point. It
produces a eutectic alloy right at the surface. Because the amount is
so small, it melts the surface for just a moment, then the copper
migrates into the metals, and for all intents and purposes, you’re
pretty much back to the main metal without significant increases in
copper content at the surface. Granulation has been widely taught and
described for both gold and silver. Metals Technic, edited by Tim
McCreight, includes a nice chapter by John Cogswell about granulating
silver using this method to acheive adherance of the grains. Any
number of other texts over the last 20 years describe the same thing
in both gold and silver…

The process mentioned in an earlier post, of using copper salts (any
of several of them can be used, but copper carbonate is a commonly
used one. Malachite, the gem stone, consists primarily of copper
carbonate, so crushed malachite is just that) is also the same basic
thing. Rather than electroplating the copper onto the gold or silver
(and dunking your parts in used pickle while also in contact with iron
IS electroplating with copper, except that you’re using the metals
themselves, in contact with iron, to generate the voltage that’s
doing the work, rather than a seperate battery or power supply),
you’re simply intruding the copper in the form of a salt that will
break down to copper oxide as it’s heated. Because there is either a
reducing atmospher used, or organic binders used which form carbon on
heating, the copper oxide is reduced by carbon to metallic copper (and
carbon monoxide plus carbon dioxide) (the carbon is a reducing agent,
whether in a hydrocarbon gas flame that’s being operated as a reducing
flame, or whether it’s in the binder itsef used next to the copper
oxide) The end result of all these methods is the same: clean metal,
either gold or silver, at below it’s melting point, but in the
presence/contact with enough copper to lower that melting point
briefly.

When granulation techniques like this were first descirbed by
Littledale in the 30’s, many jewelers still used kilns to solder/fire
larger pieces, just as is done with enamels. In such kilns, a proper
reducing atmosphere isn’t as reliably obtained, sometimes, as you can
with a fuel/air or fuel/oxy torch flame, so the use of the copper
salts with an organic binder worked more reliably than just plating
the parts with copper. Littledale described a number of salt mixtures
he’d used, of various metallic salts (not just copper) to achieve
succuss with various metals. We’ve tended to simplify things a bit
since them, dispensing with the salts and just plating copper on the
grains or bits to be fused. John Paul Miller dispensed with added
copper entirely, relying on developing a fire scale on the grains
(which is a copper oxide surface). The glue/flux solution he’d then
use to adhere the grains supplied the needed carbon, or he could do it
just with the flame itself. By simply forcing the copper already in
his gold to concentrate as an oxide on the surface, he achieved
exceptionally beautiful results in his granulated and enamelled
pieces.

You can too, especially if you take the time to understand not just
which set of steps work for you, but also WHY they work and what is
actually happening.

This stuff is already rather well published folks. It’s not rocket
science, though it can seem so the first time something really
delicate comes together for you with these techniques. Don’t be timid
with these methods. It’s not hard, instead of agonizing over how to
do a thing and writing to orchid, simply to try it a few different
ways and SEE what works. You learn more that way, too, than just
reading posts like this one.

It’s interesting to note that John Paul Miller was always reluctant
to teach or describe his methods. Not because he wanted to keep it to
himself, but just because he felt that if you considered the problem,
thought about it, and used your head, you could come up with the
answers as well as developing a deeper understanding of what happens
and why, and what you can do with it. And you won’t be as stumped
when something you didn’t expect happens, as you’ll have a better
grounding to understand what might have happened.

Copper, by the way, isn’t the only agent to reduce the melting point
of gold and silver alloys. Some high copper alloys of gold, for
example, might granulate with silver plating, not copper. Zinc salts
might work too, in some cases. And since gold carbides melt slightly
lower than fine gold, one might use carbon sources alone, with high
karat golds, to cause fusion or granulation to occur just a slight bit
easier than melting the main body of the metal. Think about it…

Peter Rowe