Sizing rhodium plated white gold rings.

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 :-)

A. You are right, you should not use a nickel underplate for rhodium plating over white gold. You are also right that a pen plater is not the right tool for this job. It is better to immerse the entire ring in a rhodium plating bath. It is possible to get great results without removing all the rhodium but it takes some careful polishing and experience. I will be happy to send you an article (which I wrote) on this subject, published last month in AJM magazine, if you contact me directly.

Any white gold alloy of 14K is 58.5% gold and gold is a yellow metal so no matter what other metal is in the alloy it will never be as white as platinum let alone rhodium. Some people are quite content with this slightly yellow color and if these people are your customers so much the better. The reason for copper in most alloys of white gold, be it sheet stock, wire, or castings, is to improve malleability. This attribute reduces the chance of the prongs that are holding stones cracking or ring shanks breaking.

A. Regarding your query regarding the repairing or resizing of a ring, you have to take special care about the finishing of the work done. You have to finish up the resizing very well without any pits and you have to polish all the ring shank very well. To do this operation, You must use a very fine abrasive paper to smooth out the rhodium plating existing before the using of the torch for resizing. Then, a very good polish first with tripoli and then with a fine polishing agent, like Magic Blue Polish using a soft cotton polishing mop. Now comes the crucial point: there should be a divine cleaning of the job done otherwise the rhodium plating would become dull or stained. The item to be plated must be electrocleaned well and then soaked in distilled water to clear off any impurities. After all this, place the ring in a Rhodium Bath and give it a 15 to 20 second bath, please be sure that the bath is warm at least 100 degrees F. Take it off the Rhodium and soak it again in distilled water and dry with a soft tissue. Now the ring repaired should look as new.

A. Hi Dana. No, the stones are non-conductive so they do not get plated. Diamonds and natural stones are left in place for the plating because they are resistant to the chemicals used. I am not sure about pearls and artificially colored stones and a few sensitive gemstones, because I'm not sure whether they are fully resistant to the acids and alkalis used in the plating.

Regards,

A. Ted's correct that most stones such as diamonds, sapphire, rubies etc. are not removed before rhodium plating and yes pearls will be attacked by the chemicals as will coral, shell, lapis lazuli, malachite, turquoise and some others. Hematite is the only gem stone that I know of that conducts electricity and will be plated along with the metal.

Thanks Neil, your actual experience trumps my second-hand hearsay knowledge.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 2016

A. Hi Juan. We appended your inquiry to a thread where Neil Bell has supplied such a list. He agrees with what you've heard about lapis lazuli and malachite.

Regards,

A. Hi Juan. The only 'list' I have is Neil Bell's posting of October 28, 2016, just above.

Regards,

A. While it may be somewhat time consuming, one could simply add an insulating coat of clear lacquer to the stone before plating, this lacquer will come off very easy with nail polish remover, but if the "Stones" are actually made out of plastics and very in expensive then that could be a problem, but for most natural stones this should not be an issue at all.