Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

Rhodium plating Q&A, woes & problems

Rhodium plating problems, brown spots and fog

Q. Occasionally, when I do rhodium plating, I get tiny brown spots on the metal. Other times I get some "fog". I have my rhodium solution checked regularly, and replace my electro-cleaner regularly. Any ideas as to what may be causing this and how to correct it?

A. Usually brown spots mean that acid has been absorbed into tiny crevices, pores in the base metal, only to leach out after plating and drying. Use less concentrated solutions, less porous metals, and flush porosity with hot and cold rinses.

  
Tom Pullizzi
Falls Township, Pennsylvania
2001

Jeweler has rhodium plating problem: burning of tips of claws

Q. I am a jeweler and was wondering if anyone has any explanation for the following. Could someone please explain why when I rhodium plate a white gold claw set ring, why do the tips of the claws become blackened. (Burnt in the process of rhodium plating?) Particularly when we are masking off to rhodium coat two-tone pieces of jewelry. We are using 6 Volt battery charger ⇦this on eBay or Amazon [affil links] on low end.

Any help/suggestions would be appreciated.

---

Rhodium Plating Solution

on Amazon

(affil links)

A. Because your voltage is too high. Get a better power supply.

James Watts
- Navarre, Florida
2003

A. Six volts is too high for rhodium, particularly if you are plating one ring at a time. Yes, you are "burning" the prong tips, which are a very high current density area. The current needs to be below 60 ASF and on a single ring this is only about 0.3 or 0.4 amps. Less if you are masking some of the surface.

Neil Bell
Red Sky Plating

Albuquerque, New Mexico

2003

Q. Hello,

I'm hoping I can get some advice about plating.

Let me go straight to it: I sometimes need to rhodium plate, or yellow gold plate jewelry (mostly watch cases) items. I bought a 25 amp plating machine, along with rhodium, copper, nickel and 18k yellow solutions, plus all the correct anodes (platinized titanium for rhodium, the one that looks like a grille, from a supplier in Los Angeles).

My first 2 items to plate were a white gold watch case (to be first nickel and then rhodium plated), and a sterling silver money clip (which holds a silver coin, to be first copper and then 18k yellow plated).

I perfectly polished both items (really removed the old rhodium), had them in the ultrasonic (used magic green) for 25 minutes, and steam cleaner ⇦this on eBay or Amazon [affil links] them until they were red hot, the items were clean.

After that I wrapped them with watch paper (didn't touch them with my bare hands at all), left them untouched for a few days, and proceeded to plate them.

Using thin latex gloves I attached 14k gold wire (yellow for the money clip, and white for the watch case) in a way that there was good electrical contact.

I first nickel plated the watch case, and copper plated the money clip; then I proceed to rhodium plate and 18k yellow plate them respectively.

I used a pint of solution in all cases, heated the solutions to the recommended temperature (a plating book that I got along with the supplies), had the voltage to the recommended values (when recommendation was between 4 & 6 volts I used either 4 or 5 volts), moved the items slightly while plating, turning them, and kept them in the plating solution no longer than the specified time. Used a platinized titanium anode and a 24K gold for the yellow, plus nickel and copper with the respective solutions.

The solutions were brand new, the thermometer was rinsed and dried between solutions, and the items being plated were rinsed in tap water and dried with clean paper towels between platings.

In short, I followed instructions to the letter, but the results were very disappointing: Copper showed through the yellow gold plating, and there were gray spots in the watch case, plus microscopic dimples spread around. Really poor quality.

I actually let the money clip stay a few seconds longer in the gold solution (could see it wasn't getting coverage), all to no avail: I didn't even get a shiny finish in it, just in a few areas it was really yellow and shiny, rest was dull and copper-ish in color, and the rhodium was really disappointing. I actually had to re-polish the case and sent it back without any rhodium plate on it.

Sorry for such a long "question", but, is it hopeless? Should I just give up altogether or is there a way to obtain satisfactory results plating? The main difficulty is that the watch cases I work with are rather high grade, and their owners are demanding as well. I imagine I can never duplicate a factory finish, but is there a way to get quality plating other than what's explained in the plating books? And I did polish and clean to perfection.

Thank you very much if you can find the time to offer me some advice.

A. That sounds so frustrating! I am getting ready to purchase a plating set-up. Please let me know what response you received to your question. If I can help in any way or share information I learn, let me know. Take care and good luck!

Stephanie Swanson
jewelry designer - Chesterton, Indiana, USA
2004

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"Plating, Brazing, Soldering & Welding "

on AbeBooks

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A. Sorry for your troubles, Mr. Iglesias. Electroplating can be a difficult subject. But I think the principal cause of your particular problem was the 'wait time' between preparation and plating, and the lack of an activating acid dip. Electroplating is an electrochemical process that can only bond to a surface that is not only perfectly clean but is an 'active' metal as well. Most metals tarnish very quickly, and tarnish is a metal oxide or metal sulfide to which plating cannot bond properly.

You should clean and acid dip immediately before plating. If this is not practical, at the least you need to acid dip immediately before plating. Which acid to use depends on the substrate and the metal you are plating it with, but 10 percent sulfuric acid is often used on brass. If it's leaded brass, you also need hydrofluoric acid, which is the one material used in plating that terrifies experienced practitioners because the burns are so dangerous, and it shouldn't be used except in an industrial setting.

You can get a finish that matches the quality of a factory finish, but plating is a skill and it is difficult to learn enough merely by reading an instruction manual. Most good platers have years of experience and were trained from the get-go by other experienced platers. Try to get some hands-on help if at all possible; if not experiment on scrap. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

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A. Hi, interesting problem. I fully agree that one should not leave polished items for plating lying around for too long before plating. Immediately after preparation is vital. In my experience using the mesh anode is not always the best way, I use real platinum and a highly polished stainless steel negative when plating white gold items. Also try heating up your plating solutions before using it. Are you making up your own concoctions or are you buying them ready made? The rhodium solution I'm using only requires me to add 1 litre of distilled water per gram of rhodium solution -- let me know please. Lastly I would like to add that if there is any kind of dust or polish dirt that comes into contact with your solutions it can and will poison your rhodium bath. Hope you resolve your challenges.

Regards,

Andre Ford
- Cape Town, South Africa
April 16, 2010

Black rhodium plating problems

Q. Dear Sir and Madam, greetings to you all.

I am a designer and a jeweler in my country. I'm very much interested in learning new techniques in manufacturing jewelry so as to upgrade and enhance my designs and finishings in the jewelry I do for my clients. I would like to learn the proper process of doing black gold Rhodium plating [adv: black rhodium plating solution on eBay or Amazon [affil links] onto K18 white and yellow gold metal. I have tried many times to plate in black gold rhodium but the desired color does not come out to be what I have expected.The finish is not in a matte black finish like the other jewelry I see in the trade fairs and in magazines. And also I'm very much interested in learning the technique that Phillip Charriol uses to do with his cable wire watch bungles and bracelets they used in their jewelry. The finish is a very matte black finish. Thank you and hoping that your company will be able to assist me in the proper process in doing this black gold metal platings, and also in enameling finishings.

Thank you again and waiting for your reply.

Sincerely yours,

Q. Hi. I work for a family owned jeweler and recently have been having trouble pen plating black rhodium over white gold to accent black diamond pave. Our problem is that initially it plates very black, but after an hour or so, it has a brown to orangish tint to it. We have tried different plating solutions from various vendors, but with the same results. We have followed the products' directions (what little there is) as far as voltage and such, prepared the piece as carefully as possible (ultrasonic cleaning, electroclean, distilled water rinses activation bath, etc.) to no avail. This is an important step in the appearance of the pieces and it is very frustrating to not get the desired results! What can we do?
Thanks.

Consumer problem of brown "slashes" on rhodium plated sterling silver

Q. I was wondering if anybody here knows of a home remedy or solution to removing brown spots or slashes out of Rhodium plated Sterling Silver. My engagement ring is made of this and it has developed these brown slashes all over, I've been taking it off when cleaning the house or dishes, and steam cleaning it only, but the slashes still appeared. Is there any way of fixing this problem without getting it re-plated? Thank You.

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Silver Polishing Cloth

on eBay or

Amazon

(affil links)

A. Hi Stacy. I'm not understanding these "brown slashes", so I'm working in the dark, and a photo would probably help. But rhodium plating is cracked, and perhaps the silver is tarnishing at the cracks. Patient use of a silver cleaner or silver polishing cloth.
would probably help, but if the "anti-tarnish" layer of rhodium is gone, the silver will readily tarnish. If the silver is gone, the underlying ring material may corrode. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2013

Cloudiness problem is rhodium plating

Q. Hi, this is Ramy Asaad.
We have been getting white spotting on my pieces' surfaces; it resembles clouds. We try to clean everything, and we are make new solution but nothings helped.
We need your help if you can!
Thank you

Is Rhodium Plating dangerous

Q. I am looking to Rhodium plate custom jewelry in my apartment. I am curious about the dangers of Rhodium plating and if there are other safe alternatives out there. Ideally, I want a way to safely plate a white color (be it Rhodium or other) and a yellow color (gold or other). I have done some research on cold Rhodium plating and heard that it is safe because it doesn't emit any fumes. I was also curious if the Rhodium plating pens are safer then the Rhodium plating baths. Any suggestions and advice would be greatly appreciated.

Q. Hi. We have a jewellery manufacturing company here in Dubai. We are facing a problem while plating black rhodium. After plating black rhodium on highly polished surface of gold 21k or 22k, black rhodium comes off just from rubbing by hands. Either it's a voltage problem or solution problem. I tried both ruthenium and black rhodium. Please give me any idea or suggestion regarding this problem. Thanks and regards.

A. Hi Nasir. A highly polished surface implies the use of compounds to achieve it -- which you may not have fully removed. Have you done a simple water-break test to verify for sure that the surface is clean?

Regards,

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

Q. Hello,

We are a jewellery manufacturer based in Mumbai.
We usually mostly work on gold and silver pieces, but recently started brass costume jewellery as well.

However, we have not much knowledge on how plating works on brass (we do have a plating plant with an inbuilt rectifier).
We usually do flash palladium then flash rhodium on silver pieces.

What would be the best solution for brass if we would like to give a guarantee of at least 6 month-1 year? We can use nickel as well.

We are a little confused because some people advised us to do cyanide copper, then nickel then rhodium, but other people told us that cyanide copper isn't required if nickel is there.

But I also heard that if we directly plate nickel over brass without preparing with copper, the nickel will peel off ?

We have a few pieces which are very large (it's basically costume jewellery) but they would physically fit in a 3L beaker [beakers on eBay or Amazon [affil links] [beakers on eBay or Amazon [affil links] .

There is also the idea of outsourcing the plating, but I guess if we can do it with our own equipment we could save a lot knowing that they charge by grams here.

Jewelry store rhodium plated my ring, but it's dull and black

Q. Has anyone ever sent their white gold ring to get a rhodium plating and the gold turned black? This happened to me at a reputable jeweler. They claim the rhodium temperature was too hot and that caused the blackness. My beautiful shiny ring now looks dull and black. they also claim they can fix this with acid. Is this true? Please help because I have my doubts. It's my anniversary ring.

Thank you,
Michele

A. Hi Michele. I think I'd try a different place than the one that screwed it up :-)

It's very unlikely that any permanent damage was done, though; rhodium is very thin and shouldn't really affect the ring. Usually rhodium is removed by polishing away mechanically rather than with acid because I don't think there is any acid that can dissolve rhodium but not gold.

Regards,

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

Non-porous finish material Q. I'm new to plating and finishing, so forgive my ignorance. I am looking to finish some very small parts that have nickel and gold elements that need absolute corrosion control in a salty brine environment. I've tried electroplating rhodium but it seems to be too porous, even at 50 micron thickness. Is there another material with similar or better corrosion resistance but is not porous? Or maybe another process would be better? - Gary Gary Chandler product designer - Seattle, Washington, USA March 17, 2017 Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?) A. Hi Gary. Rhodium probably isn't a good choice because it tends to be thin, cracked, and porous. Gold plating would be much better, and probably needn't be anywhere near that thick. Electroless nickel would probably be fine too, and much cheaper. Good luck. Regards, Ted Mooney, P.E. RET Striving to live Aloha finishing.com - Pine Beach, New Jersey March 2017

Q. Hello I have been rhodium plating silver jewelry for a while now, and in most cases once I finish the process, I get the jewel with some bubbles and I have to polish and re plate. I do not know if there is a problem with the nickel, or the rhodium plate. I've changed the electrocleaner and the nickel due to this, but the problem persists. Today I got some drag lines and bubbles in the surface of my jewel, and I've had to plate it twice now and I still get the same result. Can someone help me please?

A. Hi Maria. This sounds like a lack of adhesion and most likely the surface of your silver is not clean enough to create a good bond. Also you don't mention an acid dip and you should be using one between the electrocleaner and the plating bath with a rinse after each step. Porosity in your silver items can also cause blisters to appear in the plating. Neil Bell Red Sky Plating Albuquerque, New Mexico January 18, 2018 A. Hi Maria, Have you tried just plating the nickel to see if you get the same problem there? If you do it's a fairly good indicator that the nickel is the problem. Without further details about your process it's hard to be more specific. How are you activating the surface prior to plating? Brendan McNamara - Rochester, New York, USA January 18, 2018

Q. Hello,

I ordered 5000 rhodium plated bangles with disc on them. The design has black ink stamping on them. Unfortunately, there are ink smudges all over the discs. I tried controlling with cotton swabs with alcohol and also tried with nail polish remover. Both do not work, do you have another recommended solution to get the ink smudges off these bracelets ?? Help !!

Thank you,

A. Hi Panida. It's probably best to try to find out what solvent the ink pigment was dissolved in, as that may remove it. I think methylene chloride, Aircraft Stripper, will remove it, but it's very noxious stuff requiring gloves, goggles, and very good ventilation at the least.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2018

Q. Hello, I bought a white gold wheat chain and was unaware of the process. When the yellow started coming thru, I took it to a jeweler to have it re-rhodiumed. When it came back it really didn't look that great and I paid $55 for the process. So I took it to another jeweler and he said that the weave was too tight and he could not Rhodium because it would have "clumped". Is this true?

Ty

A. Hi Carol. There are many weights, patterns, and sizes of "wheat chain", so the question is not quite as clear as you might think. But it is entirely feasible to plate most jewelry chain. It can be a little extra work to properly jiggle it for good plating, but the plating is so thin that it's unlikely to "clump". One gold plating supplier I know of used to bring their equipment and chemicals to places where school kids could hang chains into the vat and plate them. So I'd say the 2nd jeweler may not have much plating experience.

If you are unsatisfied with what the first jeweler did, you may have proper grounds to negotiate a reduced price. But if you're thinking he didn't actually do anything based on the second jeweler's statement, I don't think that is valid.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 2018

Q. Hi, my name is Shannon from Minnesota -- my question is regarding a sudden reaction to my 10 year old wedding ring {set}.
About 10 months ago an itchy rash developed around my ring finger, as well as the insides of my pinky and middle fingers that are on either side of my ring finger.
I went to a Dermatologist who is certain that I've developed an allergy to my ring that is white gold. After having my ring dipped again in Rhodium, my fingers still itch, crack and peel when I wear my ring...
Does this indicate a true allergy to the metals of my ring? The Dermatologist stated that I will need a new ring, made of Platinum. I'm trying to find definitive information that this is truly the case.
Any direction or help would be greatly appreciated!
Thank you -

August 2019

A. Hi Shannon. Thanks for trusting your dermatologist about what the problem is because some people ask us to confirm or refute a dermatologist's diagnosis, and we are certainly completely unqualified to do that :-)

But as we move into the area of what you can do to avoid contact with an offending metal, now you are wandering onto our turf. The metal allergy you are suffering is almost surely to nickel because that is a very common and well documented one, and allergy increases over time as exposure increases. Almost all white gold sold in America has nickel in it, and some rhodium plating has nickel plating under it, so that is the source of the nickel.

Rhodium plating is very thin and it tends to be cracked like the mud of a dry lake bed. So it is not a surprise that having the ring replated with rhodium didn't help much. Tiny amounts of conductive salty perspiration can permeate that 'cracked lake bed' and put you into contact with nickel despite the rhodium plating.

Nickel Guard

on eBay or

Amazon

(affil links)

The easiest resolution, although temporary and maybe not satisfactory to you, is to coat your ring with lacquer. Clear nail polish or polyurethane can do it, but there are proprietary products formulated for the situation. Sending your ring out for platinum plating is also a possibility. Note though that platinum does not have the same brilliant shine as rhodium. As for creams & ointments and such, you're back into the dermatologists bailiwick, not mine :-)

Regards,

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

Q. Hi. I'm a jewelry Designer and I have been having issues with my Rhodium plated Sterling silver pieces coming back from my manufacturer with lighter colored dots all over the pieces. The surface area on my high polished pieces appear a light grey-ish color and then the lighter spots look like water dots (round dots) What could be causing this. Also, they are first plating with palladium and then rhodium. I would love your thoughts on this! Thanks In Advance!

August 2019

A. Hi Crystalyn. Please send some well-focused pics to for inclusion here if you can. Then there might be a fighting chance; without them, sorry, no chance :-(

Troubleshooting a plating problem usually involves at least these 5 steps from Larry Durney's "Trouble in Your Tank": Is the plating shop obeying the letter of the law as far as process control limits; walking the line to see what they are actually doing; looking at the records; looking for the pattern; looking at the parts.

Trying to help a shop which is having a problem with 'lighter color dots all over the pieces' is sometimes do-able with their interest in solving the problem and their hands-on effort; but telling a customer what to tell their plating shop about how to fix a problem based on the customer's inspection of the parts is unfortunately a very tough road, you might be limited to finding another shop who does a better job for you -- but good luck!

Regards,

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

Q. Hi. I get a dusting of what seems to be rhodium dust on my finished product of gold jewelry when I plate with rhodium. Could it be my anode? I have changed my rhodium with new solution 3 times & this still occurs. Thanks, George.

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Ed. note: Readers may also wish to review:
Topic 9975 "Rhodium plating problems and troubleshooting" and
Topic 42108, "Rhodium Spotting Problems: black spots, brown spots"
Or search the site for many others.