John-- (foot in mouth disease) Maybe you (or someone out there) can
"redeem yourself" by answering a different question… I’m
disappointed that no one has seized on the question about using
copper carbonate for fusing. I happen to have a pound of it, so I’d
really like to know whether mixing it with flux or flux and hide
glue will encourage fusing. Since it is copper carbonate, will it
also supply the needed carbon? It’s a solid-- so will it supply
anything? I tried it for fusing silver to silver, but can’t really
say for sure how well it worked.I can say it did no harm… I also
fuse gold to silver, but haven’t tried it for that yet. I’m teaching
a workshop on silver fusing this weekend, so it would be great to
figure out whether copper carb is a help! Thanks for any help!
–Noel
John-- (foot in mouth disease) Maybe you (or someone out there) can "redeem yourself" by answering a different question...
G’day Firstly, thank you for still having some faith in me. Secondly
I have never done granulation
I'm disappointed that no one has seized on the question about using copper carbonate for fusing. Since it is copper *carbonate*, will it also supply the needed carbon?
No. Upon heating copper carbonate, carbon dioxide gas is driven
off, leaving copper oxide As I understand the process of granulation,
the organic glue, such as hide glue, will supply the carbon required
to reduce the copper oxide to copper, and flux will help the area
stay clean during the heating. It is thus important that whatever
glue is used to hold the granules to the base material should be
free from other inorganic contamination
It's a solid-- so will it supply anything? I tried it for fusing silver to silver,
Copper carbonate is insoluble in anything except acids and very
strong alkalies. and you use neither. When mixed with flux and
organic glue it should provide the necessary copper upon heating
strongly to lower the melting point at the interface of the granule
and base, and thus ‘fuse’ . I understand that the ancients used
ground malachite, which contains copper carbonate, plus an hydroxyl
ion (OH) But that disappears with heating too. Those old blokes were
pretty clued up., eh?
Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ
I'm teaching a workshop on silver fusing this weekend, so it would be great to figure out whether copper carb is a help! Thanks for any help! --Noel
Noel… I’m just now learning the techniques and relying a lot on
Oppi’s observation of traditional techniques. Looking in the index
of his ‘bible’, the only time he refers to using copper carbonate is
to color metals. Specifically, it is used with other ingredients to
color brass a blue-black and a yellow to bright red.
When fusing granules, he either plates copper on the granules with
the spent pickle technique or intentional firescale prior to placing
on the base piece, or he adds one of the following to the organic
binder: copper hydroxide, copper chloride, copper sulphate, or
copper acetate.
His photo of a Nepalese goldworker fusing a granulated 22K nose ring
with a kerosene lamp and a blowpipe while it sits on a mica sheet on
a handheld piece of charred wood is quite humbling! (see pg 349 of
his Jewelry Concepts and Technology)
Donna in Dallas