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Black spots under glass stone?


#1

hello everyone,

as i’m fairly new to metalwork, i could use some help figuring out
what is going on with a bezel set, fused glass and sterling ring
that i made recently. the lady who commissioned it has since
complained that there are some small, spreading black spots under
the translucent glass stone. i couldn’t figure what it could be and
suggested she soak it in ammonia and see if that helped. she
reported back to me that the largest spot seemed to get smaller but
that there were still little bits that she could see under that
stone. since i have been experimenting with techniques and tools,
the only thing i could figure is that i may have burnished the
inside of the setting using a little steel brush on my flexshaft-
and although i’d like to think i washed it afterwards, i may have
eyeballed it, determined it was clean and set the stone- and the
brush left a residue that rusted when she washed her hands a few
times with the ring on? is this possible?

and my main question is- can it be remedied by soaking in something
like CLR or should i chalk it up to lovely ole experience and make
her a new one being careful to watch my steps?

(the wierd thing is that i’ve been on a ring making frenzy ever
since i got my kiln and have worn many others numerous times with no
problems. stands to reason that it’s the one that gets sold that
develops problems! )

any advice is greatly appreciated- particularly the advice that
keeps me from having to make her a new one!!!

hayley


#2
    as i'm fairly new to metalwork, i could use some help figuring
out what is going on with a bezel set, fused glass and sterling
ring that i made recently. 

Hi Hayley. It is difficult to troubleshoot your problem without
seeing it firsthand. You don’t even mention which metal you used to
make the ring. Further soaking may resolve the problem, or not. Many
new metalworkers create mountings for bezel or prong set stones
without making at least a small hole at the back for ease of
cleaning the stone and mounting, and I’m wondering if that is the
case with yours. If so, do yourself (and your customers) a favor and
always provide access to the inside back of the mounting via a hole
of some kind.

I’m only assuming that you’re using closed-back mountings because
you haven’t mentioned using a brush of some kind, only soaking.
Without being able to easily clean the back of the stone, it will
eventually collect grease, dust, etc., and that changes the
refractive index of the stone, rendering it dull and lifeless, not
to mention spotted with the occasional black dots.

I’m sorry if I didn’t address your current problem or provide the
solution that doesn’t require you to make your customer another
ring. Maybe some more specific info will help?

James in SoFl


#3

Haylay,

Sounds like you have silver oxidizing under your stone. Ammonia
tends to mess up the finish on silver so I would not recommend
soaking silver in ammonia… You cold remove the stone and put a non
oxidizing bed under it such as silver colored Mylar. Cut a piece of
the Mylar (Mylar is basically silvered plastic.) the shape of your
stone and put it into your bezel cup. Put the stone in and reset it.

Regards
J Morley/Goldsmith Laser Welding


#4

Haley,

Carefully remove the fused glass from the bezel. Cut a piece of
stainless steel foil to fit into the bezel under the glass, reset
the fused glass. You may have to anneal the ring after removing the
glass to make it easier to push the bezel over a second time.
Alternately, you can leave air line openings around the base of the
bezel when you are setting transparent objects. This will facilitate
cleaning. You can see an example at:

http://www.brixnerdesign.net/samples/airline.htm

Steven Brixner
www.brixnerdesign.com


#5
    Sounds like you have silver oxidizing under your stone.
Ammonia tends to mess up the finish on silver so I would not
recommend soaking silver in ammonia... 

That’s what I thought! Then someone challenged me on that and I
couldn’t find any on it, so I thought I must be confusing
silver with copper.

Doesn’t ammonia cause surface changes to sterling? After all, there
is copper in sterling, so if it patinates copper (which ammonia does,
if I’m recalling THAT correctly) then it seems logical that it should
do SOMETHING to alloys containing copper. Since the copper remains
distinct crystal-wise from the silver, it should still react to any
chemical it usually would, even if that chemical is inert or would
have no reaction with pure silver.

Sojourner