We are manufacturing brass and Sterling silver jewelry.
Currently we are silver plating it to give a base coat, then gold plating and finally giving an ecoat using Axalta’s lacquer.
One of the major concern is that what base coat should we use on brass to prevent tarnish.
My jewelry surface have metal porosity issues most of the time, which later on create a trouble as they form bubbles and white spots on the surface.
we are using lacquer with 10-11 degrees preparation and then ecoat it for 10 seconds on 30 volts and then cure it in a kiln for 30 minutes at 130 degrees. This doesnt looks sufficient to me as usually it is suggested to ecoat for atleast 40-45 seconts at 40-60 volts for getting optimum results. but when i try doing that the piece becomes completely dull and is full of bubbles.
after a few uses the piece start peeling off a layer of coat which should not happen.
If you’re plating the pcs. and the quality of the casting is creating problems, you’ll never solve the problem. In my opinion the casting problem must be solved first or the problem will always be there.
Maybe the question should be “ how can I improve the quality of my casting?”
I second your thoughts. But so far we have realized, that the minor porosity problems are unavoidable with metals. Although we hammer it and get it repaired to the extent possible.
Try nickel plating instead of silver plating. Silver will not keep the copper from leaching through to the top of the gold plating. Nickel will and is cheap to make yourself.
nickel plating is an option… but my customers do not accept the nickel plating as many of their customers are allergic to it and also some countries resticts and regulates nickel plated jewelry.
I have to disagree. Rhodium is often used on silver jewelry to prevent oxidation as it helps to block the copper from mitigating to the surface.
There are numerous technical publications out you can check out on rhodium plating silver jewelry and why to do it.
Just my experience
Silver must be plated with nickel or palladium before rhodium plating. Silver will contaminate the Rhodium solution . See the attached video from Stuller How to Rhodium Plate Sterling Silver | Stuller
Jo
To the best of my knowledge sterling has to be nickel plated prior to rhodium plating or the oxidation will show through. Here is a comment from Ganoksin that I found on Google. Worth the read. Apparently you can also use palladium as an underplating.
You are correct Janet that the rhodium solution will be contaminated
if you put the silver in there directly. The trade pre-plates the
silver with nickel or some other plating that rhodium will not be
contaminated with and will adhere well. Electrocleaning is a must in
all steps.
