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Successful gold ring rhodium plating procedure  

Ed. note; This is an interesting thread, and only one of many. Before you get too confused, you might want to start with our FAQ on Rhodium Plating and White Gold to get an overall understanding :-)

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I have noted many questions on this forum regarding flaking of rhodium or other poor color results in the rhodium plating of yellow gold rings. I have personally experienced all these problems, and after much experimentation, have come up with the following procedure. I have plated six yellow gold ring sets with rhodium over palladium, with incredibly beautiful results. The process I have settled on is:

1. Buff ring to brilliant shine with Tripoli [link is to product info at Eastwood], then Fabulustre [link is to product info at Amazon].
2. Soak in 1:1 hot isopropanol:linseed oil liquid soap. Use toothbrush to clean diamonds and mounting.
3. Plate with palladium, 1 minute, 6 volts, room temperature.
4. Buff to shine with rouge cloth.
5. Repeat steps 2 - 4.
6. Soak in 1:1 hot isopropanol:linseed oil liquid soap.
7. Plate with rhodium, to a definite bluish tint compared to palladium color, about 40 seconds, 2.3 volts, room temperature.
8. Buff to shine with rouge cloth.

Two things I've learned:

1. The palladium is not only a very beautiful barrier between the yellow gold and the rhodium, but is probably the easiest thing I've ever plated. The adhesion to and color masking of the substrate are fabulous.

2. Rhodium goes over palladium better than over 14K gold, and as good as over a 24K gold underplate. Although it takes a bit longer, plate rhodium at 2.3 volts instead of 4 - 14 volts. This avoids the stress flaking you get after awhile at the higher voltages, and the adhesion is far superior. I played around a bit to find this out.

There is a difference in color between the silvery-white palladium and the more bluish-tint rhodium. However unless you really look hard, when the rhodium wears off you cannot see the difference with the palladium showing through -- a far better situation than yellow gold showing through.

The palladium and rhodium solutions I used were supplied from LDC Company, W.R. Associates, Inc.


Bob
The Silver Doctor

Robert L. Nelson, MD
The Silver Doctor - Indianapolis, IN, USA

Thanks for the great exposition, Doc -- and nickel-free to boot! My only reticence about it is that, while this is a perfect prescription for consumers who are already stuck with rings of the wrong color for their taste, I hope it's not so good an answer that jewelers expand upon the recently observed practice of plating yellow gold to make it look white. If someone buys a white gold ring, it should not merely be palladium-rhodium plated, it should be white gold alloy under that plating.

Ted Mooney, P.E.  finishing.com Brick, New Jersey