On Mon, 06 Jul 1998 04:13:02 GMT, in rec.crafts.jewelry ne33...@aol.com
(NE333RO) wrote:
>>>if you place your silver
>>>pieces into household bleach it will give you a durable black surface. The
>>>piece must be left in the bleach for a few minutes.
>>This is a question not a statement. Is bleach harmful to silver jewelry? I know
>>it will ruin gold jewelry but does it have the same effect on silver. If I
>>remember correctly it reacts poorly with the alloys in gold (making it porous
>>and brittle), will it do the same to silver?
In golds, the chloride ion in bleach acts as a slight solvent, causing more
reactive componants of the alloy to be slightly leached out. Usually, it's not
a problem with yellow gold alloys, but can bother some solders used to assemble
the piece, and with white gold alloys, bleach can leach nickle out of the alloy,
causing the porosity, brittleness and failure your mention. Since this means
the prongs holding stones in much jewelry, it's clearly something to avoid.
In silver, a similar solvent/corrosive effect is there, but in the case of
silver, it only affects the surface, giving you that tarnished appearance. The
strength of the metal is not affected, since it doesn't penatrate beyond the
surface.
It should also perhaps be mentioned that bleach as a silver oxidizer is somewhat
less than completely consistant and reliable. Leave it too long and it will end
up dirty grey and blotchy, not dark, and it never really gives you the best
black appearance. And, the surface it gives you is not as dark as that
optainable by more traditional silver oxidizers. If you simply wish a
used/anique/worn look, it may be superior. But if you want a nice clear good
looking black or dark grey, it's probably the wrong choice.
My own favorite silver oxidizer is simply liver of sulphur. While the
concentrated chemical is slightly toxic (don't eat the stuff), it's quite
biodegradable (sunlight or just time degrades the stuff) to relatively innocuous
forms, and diluted into a larger volume of water, such as when you flush it down
the drain, it's capacity for harm is pretty much removed. It most certainly
does not have anywhere close to the toxicity of the prepared silver oxidizers
containing teluric acid. These preparations are most assureadly toxic.
Ingested, they are potentially lethal. They're advantage is that they are more
reactive, working even on surface depleted sterling, and give a denser darker
black than liver of sulphur, which tends to a blue/black or dark grey tone
sometimes. I happen to prefer the latter, especially after wet scratch brushing
with a soft brass plater's brush, giveing me a nice metalic blue/black sheen.
But if what you want is a dull jet black, the prepared oxidizers might be the
choice for you, despite toxicity concerns. Bleach is rather less of a normally
used choice here. Some artists might like the results, or hobbyists might
appreciate not having to go buy something else for only sporadic needs, but it's
not considered a normal, traditional, or professional solution to oxidizing
silver.
Hope this helps.
Peter Rowe
