How to do durable silver or gold plating on musical instruments

The Sulfamate Nickel How-To Guide
by David Crotty, PhD & Robert Probert

A. Hi Julian.
You are certainly welcome to try to do this yourself, and readers are welcome to help you and will probably be happy to answer your questions. Still, you and other readers should be told, just in case you don't know, that electroplating is a well developed industrial science and industrial process, and that there are job shops with decades of experience available to undertake such jobs.

You will need an underlayer of nickel plating or white bronze tri-alloy. Normally nickel plating is shunned these days because many people develop skin allergies to it, but with 5µ of gold over it I would anticipate zero porosity and zero exposure to nickel. Tri-alloy plating is significantly more difficult, and probably essentially impossible for a hobbyist to formulate themself.

If I were you I would not attempt to plate an expensive item like a saxophone until I had acquired many months of experience gold plating smaller, simpler, sample parts. Again, it's not my intention to say what you can & can't or should & shouldn't do, but it probably is my obligation from many decades in the industry and running this site to not lead you down the primrose path. Best of luck!
Regards,


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

A. Hi again. There probably aren't too many plating shops with gold plating tanks that are big enough, but our Directory of Jobshops lists a couple, and Epner Technology in Brooklyn is probably the closest shop able to gold plate a saxophone.

Luck & Regards,


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

A. Hello Kevin,
You don't mention what type of silver or gold solutions you are using. The type and plating thickness of the deposit would be the key here. In other words a hard gold with a heavier thickness would last longer than a pure gold at 15 microinch thickness. The same would go for silver plating. Please advise.

A. It seems the gold current density may be too high. Try cutting the current in half and doubling the dwell time. Also you may need an activator for the copper/nickel surface.

A. Have you considered putting a PVD coating in lieu of the gold and silver. Gold and silver are very soft metals, and are going to wear off over time. You can get similar finishes in PVD coatings that are much harder than steel -- they were developed to cut steel. You should be able to find someone in your part of the world doing decorative PVD. Check them out -- you may need to add trivalent chromium atop the nickel, but my guess is it will be cheaper to have them do the PVD work for you than it will be to gold plate your parts in-house, and maybe even less expensive than the silver plating. The end product will hold up much better.

A. If you are seeing a degree of peeling problems, I would have a quick look at your initial cleaning process - when you mention boiling water to degrease and the use of soap and water, this step can be a strong candidate for your problems.

Consider using a degreasing agent, an alkaline clean, DI water and a quick water-break check. Then see if your process improves.

A. I agree with Scott. The gold current density is WAY too high. .6 A/in2 is 86 A/ft2. Are you sure you don't mean .06 A/in2. Even that is on the high side of normal current density for a gold cyanide bath, which is 3 to 8 A/ft2 or .02 to .055 A/in2.

A. If adhesion is the problem, then we need to know the preparation cycle. And be reminded, that if it is leaded brass, that Hydrochloric and sulfuric form insolubles on the surface that you cannot plate over -- leaded brass must be run through fluoboric acid.

A. Hi Julie. First, in case you weren't aware, there are professional plating shops who can handle this for you if you are interested in that approach..

I am aware of the Medallion Liquid Gold process, which is an immersion/replacement plating process ... but I am not personally familiar with using it as a base for subsequent electroplating, and I'm not sure that it is a good idea because immersion plating usually doesn't have the same adhesion offered by electroplating. You might be better off simply skipping that step, but I don't know whether the mouthpiece is made of solid silver, and is free of nickel or other plating, and therefore whether gold can be electroplated directly onto it.

Electrocleaning can be very important in a production environment, but I don't think it accomplishes cleaning any better than scrubbing with a pumice solution and a tampico brush. So, after scrubbing, I'd rinse well and try directly gold plating.

It's probably not FDA approved, but for personal use you could try topping the gold plating with a UV-hardened clear coat -- basically UV hardened clear nail polish. Since people often put their fingers in their mouth, it can't be that toxic :-)

Note that these ideas are for personal use, not for something you would sell. Good luck.

Regards,

A. Hi. Sorry I misread your posting. Don't give up on the nail lacquer, though. I wasn't referring to acetone-based air dry formulations, but to the Ultraviolet cured gels. Maybe take your mouthpiece to a manicure salon that offers those UV trays that you put your fingers in, and ask them to put nail lacquer on it -- you might find the taste of that less awful :-)
Another option is to purchase an "at home" gel manicure kit. They come with a UV light and the polish is readily available. And there are 'food-safe' clear coats.

Regards,

A. Hi Julie. There are two issues here, the possible danger to yourself as the plater, and the possible danger to the user...

Cyanide is an extremely powerful poison that should not be used in a residential environment or by people who don't thoroughly understand it. A small trace ingested can kill you, and it's also possible to accidentally acidify it, releasing poisonous hydrogen cyanide fumes. I'm not sure what your plating shop looks like and what expertise you have.

But as for the user, they are in no danger if you are absolutely sure that the mouthpieces are scrupulously rinsed. After all, virtually all silverplate, including flatware, is silver plated from a silver cyanide plating bath, and many foods like almonds and lima beans have traces of cyanide in them.

I'm not quite clear whether your interest is silver plating or gold, but there are many formulations for gold plating baths: some are cyanide based and some not. If you will be gold plating rather than silver plating, yes, I'd certainly be looking for a cyanide-free formulation. Silver is trickier because, although there are cyanide-free proprietaries, almost all decorative plating is done from cyanide solutions.

Regards,

A. Yes, cyanide silver plating solutions have been used for probably 150 years and are the standard. But there are proprietary silver plating solutions that are cyanide-free and, while they are not widely used for decorative silver plating, they still might suffice. I think they're worth a try.

adv: Cyanide-free silver plating solutions are available from EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser]

But, I'm not at all sure that I'd agree that cyanide gold plating solutions are better than cyanide-free. If I were you I would talk to a major supplier of gold plating chemistry about what is best for mouthpieces.

Luck & Regards,