Gold Plating Iphones and mobile phones, Q & A's

A. Hi, Chris.

There are a half-dozen different ways to metallize a non-conductive surface to begin electroplating, and they are explained in our FAQ on "Plating Organic Materials". But, as you may already know, getting good adhesion to the substrate is a principal need in most electroplating . . . and this is best done by etching and activating ABS plastics. If a local or university library has a copy of "Standards and Guidelines for Electroplated Plastics" it will be well worth getting your hands on.
Good luck.

A. Hi Chris

Plating on plastics is a large and well established industry but it is not really suitable for home use.

Your problems start by not knowing what type of plastic you are dealing with. The pre-treatment (to get adhesion) is very important and usually includes etching with chromic acid (very nasty). Some plastics are very difficult.

The parts are then coated with electroless copper to provide conductivity (a basically unstable solution)

Take a look at
https://www.youtube-nocookie.com/embed/RpZrcnFusr0 [ed.note: sorry, link is now broken]
to give some idea of the size of the process (5 tanks +) just for this stage.

Then we would electroplate copper and possibly nickel before a hefty thickness of gold to withstand constant handling probably 5 microns.

You also need to understand the chemistry to control it and be able to recover your client's phone case if it goes wrong. Ask your local authority about disposal of hexavalent chrome before rushing into this!

Which may give some idea why you see so few gold plated phones.

A. Hi, J.

Gold plated watches from many decades ago still have their gold plating. Gold does not wear quickly. The primary problem is that the plating that people are applying today is 50 times thinner, and the amount that they want to apply offers no wear resistance and is just barely enough to offer color.

There are countless lacquers and clearcoats. Lacquer is easily removed with thinner and replaced, so it finds wide use. I think a UV-curable clear enamel will offer the greatest hardness, and you can get an inexpensive sample and curing light to try it..

Alternately, a two-component automotive clear coat should be good. Best of luck, and let us know what route you chose and how it worked out.

Regards,

A. Hello J Searle,
I am using a UV curing electro-lacquer over my 24 carat gold plate with excellent results. Would you like more information on this?

Hi, Mike. There are hundreds of readers for each poster, so please publicly share any technical (non-commercial) info you can. The combination of electrophoretic application for keeping the film really thin, plus UV curing for maximum hardness sounds great.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
August 8, 2012

A. Pure gold is soft and a mobile phone sees a lot of wear.
Ask your process supplier for a hard gold alloy and explain the use. This is a well known problem and they have the solution.
Unless you are a very experienced process chemist and willing to spend a lot of time and money on developing a hard gold bath, I would not waste energy on trying to develop your own.
You will still need to plate a significant thickness, say 5 microns. Fortunately most plating baths will plate thicker at the edges of the part which is also probably the area of greatest wear and you can enhance this by careful jigging.

A. Hello,

Regarding the durability issue of the phone cases, wouldn't PVD be much more suited in this case?

Thank you

Hi Seb. Yes, thanks! For those who are interested in mass production, PVD sounds attractive. But it involves a $1-million-plus installation, so it's not highly applicable to onezy-twozy applications.

Regards,

A. Hi cousin Aida. Surely you can buy waxes or lacquers rather than having to formulate your own from raw chemicals? The consensus seems to be that UV-cured electrophoretic lacquers are best, but if you do not have an electrocoating setup, it probably is possible to use brass lacquer, or UV-hardening nail lacquer, or a two-component automotive clearcoat. You could also try museum wax, but it's durability would be very limited.

Can you please explain the application? I understand it's for use on gold plated ABS, but that still leaves a lot of room. For example, is this for exterior automotive application (very severe exposure) or for a lighting fixture inside an air conditioned office (mild exposure)? How long do you expect it to last, how thick is the gold plating, etc. Good luck.

Regards,

A. It has been my experience using both 2k automotive clear and UV cured Nail polish that transparent base coats are much better retaining an authentic metal look. I use what is called transparent base coat (both 2k and UV cured) which is basically a pigment free base coat; this coat is not glossy but transparent and if painted over a matte surface will remain matte, or if painted over a mirror like surface it will retain a mirror look. I have used this successfully over Copper, Silver and gold without issues at all. The base coat has a better grip over the polished metal surface than glossy clear coats that are meant to go over matte base coats and will often peel off from polished metal surfaces and when they are too glossy will not produce a natural appearance.

Thanks Marvin. I did not understand your wisdom immediately, but now I see that by "transparent base coats", you are referring to a paint base what would normally be mixed with a pigment or coloring agent to make an automotive color paint. Thus indeed, this could be formulated to stick to raw metal whereas automotive clear coats are formulated to stick to other paints. This makes a great deal of sense!

Regards,

A. You are correct Mr. Mooney. In the automotive coating world these type of colorless base coats are called "Mixing clears". They can be catalyzed (2k hardeners) to make them very durable and also add UV inhibitors. They offer a more realistic or true-to-type metal look than glossy clear coats.

A. Hi Max,
Sure, apply a lacquer but only on the exposed areas and specify hard gold. What is the specified Au thickness?

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Ed. note: Letter 30273, "Lacquer for gold plating", addresses very similar issues.

A. Hi Dani. That question is probably going to be too broad for a direct response. Please thumb through a couple of the applicable chapters in the Metal Finishing Guidebook, then you'll be able to ask a question which people will hopefully be able to answer. Good luck.

Regards,

A. Hi Muhammad,

You may either increase gold plating thickness follow by pore blocker treatment (a chemical post treatment that block any gold porosity after plating that may expose underlying nickel in microscopic) or consider PVD (physical vapor deposition) which could be more durable in long run.

Regards,
David