Elizabeth T Showers
Elizabeth Showers, Inc.
Dallas, TX. USA
Hello–
I have had a jewelry business for 9 years – we are introducing a
new collection of jewelry that is made with a different process than
what we have known for 9 years. We are putting 18k yellow gold
detail onto sterling silver, and doing a sandblasted finish on the
silver portion as well as rhodium-plating the silver portion. We
are having problems with the solder joints oxydizing after the
jewelry is worn for 2-3 months–we were hoping that the plate was
thick enough to cover up this issue, but apparently not (and we are
not wanting to oxydize in the crevices to hide this problem). We
are just about to try some suggested techniques/ideas, but I would
like to hear any suggestions and/or experience that any of you could
share. Thanks so much–Elizabeth
Elizabeth,
Plating is one of those techniques I try to avoid. But in my many
years spent repairing rhodium plated silver there was always a
copper flash followed by a fairly heavy bright nickel before the
final rhodium. The copper for adhesion and the nickel to ‘seal’ the
surface (against oxidation). And I was always under the impression
that straight silver would poison to the rhodium bath chemistry
($$$).
Another thought is to avoid the use of easy solders, they tend to be
a poor colour match at the best of times and oxidise quickly. Hard
silver solder does not re-melt easily, and each re-heating seems to
raise the re-melt temperature of previous joints. Usually I just use
hard solder unless doing a repair job or attaching a commercial
finding.
Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand
jdemand@gmavt.net
Elizabeth,
We are putting 18k yellow gold detail onto sterling silver, and
doing a sandblasted finish on the silver portion as well as
rhodium-plating the silver portion. We are having problems with
the solder joints oxydizing after the jewelry is worn for 2-3
months--we were hoping that the plate was thick enough to cover up
this issue, but apparently not (and we are not wanting to oxydize
in the crevices to hide this problem).
I am a Goldsmith in Boulder Colorado. I have had experience in
plating, as I manufactured a gold plated line a few years back. You
probably know this already but I will share with you what I know and
try to figure out a fix for your problem. I am assuming you have
hands on in the making of your pieces. I would suggest buying or
building a pen plating unit. This would allow you to replate the
pieces with a thicker layer of rhodium. If the layer of plating is
not thick enough the host metal will show through. It is a hand held
plating pen that can be used with rhodium or any plating solution.
This might be a quick fix unless you have five thousand units to
fix. When plating the pieces we manufactured we used a copper base
then a nickel layer then gold this is a standard way to plate. Nickel
is very shiny and allows for a thinner layer of gold to be applied.
The nickel actually shines through the gold. This is very important;
through every step of any plating process the pieces being plated
must be clean. Professional plating companies use a chemical
cleaning process to pre clean parts. Beyond the fix I would consider
a few other avenues when manufacturing your pieces. I am kind of in
the dark as far as what the problem pieces look like but I will ad my
two cents anyway. You can use a new sterling silver ultra white
alloy it does not tarnish and it will not fire scale. I believe they
are manufacturing ultra white solder also. I don’t cast a bunch of
silver but it is the only silver alloy I will use. You could try
fusing the 18k to the silver (no solder) You could laser weld the
18k to the sterling (no solder I happen to have a laser welder) You
could mechanically attach the 18k pieces to the silver. Put posts on
the back of the 18k and laser solder from behind or rivet. I am also
assuming that at the finishing phase of your manufacturing you are
rhodium plating the pieces as a last step before they are tumbled or
buffed. If not you will remove the plating. If you can e-mail me
pictures I could probably help more. If you have any further
questions e-mail me or call me @ 303-931-4225
Regards J Morley/Goldsmith/Laser welding
944 Pearl Unit G
Boulder, Colorado 80501