How to solder granulated silver ?

[billary...@hotmail.com]

Does one how to make "granulated silver" ?
This technique is used on, particularly Balinese silver
jewelry. On a ring there are decorations with small
(1-2 mm or 1/16" diameter) spheres of silver.

How should these be fixed on the silver. I know that
'ordinary' soldering does not work, but something with
cupric oxide (CuO) and charcoal ?

Thanks,

Klaas

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[Steve Smith]

> Does one how to make "granulated silver" ?
> This technique is used on, particularly Balinese silver
> jewelry. On a ring there are decorations with small
> (1-2 mm or 1/16" diameter) spheres of silver.

I make my granules by heating bits of silver on an insulating surface. I
make the bits by rolling sheet as thin as I can, and then cutting out
squares of silver (I use pretty small balls in some cases). Spread the
squares out on the insulator, and heat with a torch. You will want to use a
quite small flame so that the silver doesn't roll all over when it melts.
The surface tension will pull the silver into a nice ball. Pickle them
thoroughly. Sort them for size.

I use a dissecting microscope and tweezers to place the balls. First, paint
the surface with your copper solution (see below). Put the balls on it, and
shove them around until they are in the right places. This can be a bit
tricky--patience is important (along with not drinking too much coffee).
You may find that you want to place the balls with the copper solution just
tacky.

> How should these be fixed on the silver. I know that
> 'ordinary' soldering does not work, but something with
> cupric oxide (CuO) and charcoal ?
>
> Thanks,
>
> Klaas

Ordinary soldering will usually flood the balls. Instead of mechanically
applying solder, apply it chemically (as you are referring to above). The
approach I use (on sterling silver by the way) is to wet the surface with a
solution of copper carbonate and white glue, which gets sucked into all the
joints between the balls and whatever they are touching.

Let the piece dry THOROUGHLY. If it isn't completely dry when you start
heating, the balls will move around.

The idea is that as you heat the copper salt solution, the glue burns to
carbon (thus your formula's charcoal). This carbon burns, providing a
reducing atmosphere, and the copper salt refines itself into pure copper,
in a thin layer all over the surface of the silver. As you continue
heating, you will hit the eutectic point, where the copper and silver are
mutually soluble. About here, the whole surface will flash molten, and your
balls should be stuck down. Remove heat and pickle. There should now be a
tiny amount of solder in just the right places. Check your balls to make
sure they all are stuck down. If not, add some more copper solution and try
again (after pickling). You will appreciate by this point that some
practice is advisable.

Other solutions should also work (such as your cupric oxide and charcoal),
but I haven't tried them. I'm suspicious that powdered malachite would also
work.

Steve Smith
Loveland, Co.

[Ralph Gibson]

Hello,

Wouldn't heating powdered malachite with a torch result in the release of
toxic gasses?

--
Gibson's Jewelry
http://home.inreach.com/linus
gibsons...@hotmail.com

Steve Smith <ste...@kotamicro.com> wrote in article
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>
> SNIP