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18K Yellow gold mysterious color change


#1

The 18K yellow gold ring came out of the ultrasonic white! Polished
an area to see if it was some weird galvanic reaction…still white.
So I figured it might be a yellow plated white gold piece and the
plating just flaked off, and I’ll have to re-gild it. Did my
soldering and whoa its yellow again! I’ve had numerous other pieces
in the same bath with no change whatsoever. I wonder if I just
exposed myself to a big dose of mercury vapors? But how it might have
gotten there I dunno.

Cue the Twilight Zone theme.


#2

The 18K yellow gold ring came out of the ultrasonic white! This
happens to me occasionally, too. I’d love to know what’s going on as
well. I’ve been able to get back to yellow through polishing,
though.

Matthew Crawford
www.MatthewDesigns.com


#3

Hi

Sounds like mercury to me, hope you exhauled while soldering. its a
good habit to form.

Robert L. Martin
Goldsmith/Platinumsmith


#4

Now I’m wondering if the silver in the alloy could possibly raise to
the surface. Any metallurgists have an opinion? Ultrasonic ofcourse
has a heated stainless tank, solution was ammoniated, used copper
wire to hang ring, was not a full moon.


#5
Sounds like mercury to me, hope you exhauled while soldering. its
a good habit to form. 

When I’ve seen this in the ultrasonic I have always assumed it to be
some sort of plating. If silver was left to long in the ultrasonic
and it has gone white, I’ve always figured that some silver was
leached or etched out into the solution-- especially if there is
ammonia in the solution.

With this solution acting as an electrolite and the ring as a
cathode, a dissimilar metal like a hanging hook or another ring could
act as an anode, plating the silver out of solution like a pickle pot
with saturated pickle and a steel tool.

I think…

Andy Cooperman


#6

Andy,

With this solution acting as an electrolite and the ring as a
cathode, a dissimilar metal like a hanging hook or another ring
could act as an anode, plating the silver out of solution like a
pickle pot with saturated pickle and a steel tool. 

This does seem the most plausible and among my first reactions(pardon
the pun). I am puzzled though why a polishing didn’t remove it. It
was cool though to see the white just disappear when it hit X
degrees.

I use a covered quart plastic container for the solution immersed in
the main tank, to keep ammonia smell down. There’s plenty of room so
I may start using two containers dedicated to silver/gold. Maybe I
can find a suitable plastic hook.

It would be interesting to see if I can duplicate the reaction on
purpose.


#7

I think that the plating-- if that’s what it indeed is-- can be
quite thick. Perhaps a quick buffing isn’t enough. I really can’t
think of anything else…

Take care, Andy


#8

With this solution acting as an electrolite and the ring as a
cathode, a dissimilar metal like a hanging hook or another ring
could act as an anode, plating the silver out of solution like a
pickle pot with saturated pickle and a steel tool.

could be i know silver in gold aloy and silver rings will leave
susended silver in pickle. copper wire will work well in the pickle.
stuller sells a plastic hanger for the untrasonic thats on a bar and
the hooks can be replaced.

Robert L. Martin
Goldsmith/Platinumsmith
Diamond Setter