Brass plating is too yellow, need gold color

A. I have seen a bright, light colored brass plating that could easily be mistaken for gold. However, brass will quickly tarnish unless it is lacquered; it will not remain bright and shiny by itself. So you will be confronted with the additional problem of finding a lacquer that is robust enough for your application, while remaining very clear. As you will see from earlier discussions here about lacquering mag wheels, such a coating will probably have a very limited life.

A. Good Morning,

Many years ago I ran bright brass to look like a gold finish. Cyanide copper / bright nickel [must be bright] to brass plate, just a flash over, with a "sealer" style dip afterwards ... finish very close to gold.

Hope this helps ,

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Tip:  Readers often just skip abstract questions;
       they want to learn from your actual situation.

Q. I want these details.

Nakum sunny
Student - Morbi, India
February 17, 2022

A. Hi Nakum. Unfortunately, Ron's posting is from 23 years ago; I doubt that he'll see yours.

Is there a reason you think brass plating is a better path to imitation gold, than tinted lacquer or electrophoretic lacquer on nickel plating? These days lots of 'brass plating' isn't brass plating at all, but electrophetic lacquer on bright nickel plating.

Please try to introduce yourself, the substrate you want to plate onto, your situation, and which of Ron's 4 steps you'd like us to start with / focus on.

Luck & Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2022

A. Dear Mr.Esposito,

After a long experience, I learned that the lemon/yellow brass bath is one of the most stable brass baths, except perhaps of the "white brass" solutions. Any attempt to modify this standard color of the deposit, by changing the concentration of some constituents, will result in unstable colors of the coating and many head aches. For automatic production there is no other solution. If your customer wants another tint of the deposit, you may choose between light bronze coloring ( antiquing )the deposit or applying a colored transparent solvent lacquer.

Depending of the nature of the plated objects, I think that the alternative to apply a very thin (0.06 - 0.08 µm ) layer of gold from an acid gold-cobalt bath, after nickel plating, is not be neglected. Apparently this is more expensive, but if you put in balance the cost of frequent analysis of the brass bath ,of the passivation and lacquering of the deposit and of the destruction of cyanides, gold plating may be the best treatment- for which you may also ask a better payment.

Best regards,

A. I wouldn't recommend trying to change a stable bath to satisfy one customer. You will be fighting a losing battle with all other comers. It wasn't mentioned whether you lacquer the parts or not and if they are baked after lacquer. I have turned bright brass a gold color by baking them at 285 °F for approximately 20 minutes. This will work with a "flash" deposit. If you must change your chemistry, I would recommend a 4:1 ratio of Zinc metal to copper and a 4:1 ratio of Zinc metal to free cyanide and run it at a slightly lower current density to draw out more copper. Hope this helps.

A. Plate a matte nickel or dull nickel plating on the brass panel, reduce the nickel content in the gold bath it will match the original gold colour.

A. Yes I also tried lemon yellow is the usual colour suitable for production if try to change the colour by changing composition of metal and temperature result one batch came in golden colour but next batch will change. Better idea is apply an MRF clear coat, it slightly yellow tone so light golden yellow is added if you don't want yellow wanted transparent clear use ESDEE clear.

A. Hi Awder. Unfortunately you can't simply say "I tried to electroplate and it didn't work; how do I get bright gold color on iron & stainless steel?". There's a lot to it: I have 100+ plating books, and my bookshelves are quite small compared to many :-)

Instead, please tell us with full details what you are trying to plate, and what steps you tried, and what happened. Did you buff the iron to a good finish first? Did you meticulously clean it to a waterbreak-free degree? Did you acid activate it? Did you nickel plate it before the brass plating? Was the nickel plating successful?

On thread thread 28032 you asked for a brass plating formula and we reprinted 6 of them from Lowenheim's "Electroplating" ⇦[this on eBay , Amazon, AbeBooks affil links] and "Modern Electroplating" [on AbeBooks, eBay, or Amazon affil links] ... is one of those what you tried, and it worked but the color wasn't close enough? If so, send photos making sure some recognizable things are in the picture to calibrate our eyes. I appreciate your frustration with being unable to find supplies, but unfortunately electroplating is complicated enough that you won't get a 2-paragraph public forum explanation of what to do; you'll have to go a step at a time :-)

Luck & Regards,

A. Hi again cousin Awder. I wish I knew a way to do what you want, but I don't. All I can do is put your posting on this page, which gets a lot of readers, and see if anyone has advice for you.

Luck & Regards,

Thank you so much dear sir,

Even I tried to get a consultant but none of them are responding.

A. There are many ways of creating a gold colour on iron, but the first stage is to make sure your iron substrate surface is suitable -- it needs to be very smooth and clean. The flatter/smoother it is (i.e., polished) the better the surface coating will appear.
A common way of creating a gold looking surface is to deposit tungsten carbide (WC) this is done by PVD. WC is hard, so it is also used in conjunction with a gold flash to provide a hard wearing gold coloured surface.
Secondly, you can use a brass alloy deposit -- the ratio of Cu:Zn will affect the colour, so try a range of compositions and see which one is best for you. Thirdly, you can always plate the iron with gold - but that is expensive!

A. Hi Awder. The more zinc in the deposit, the more yellow it will be; the more copper in the deposit, the more red it will be. But this still leaves two problems:
1. Brass does not look quite like gold, and it's probably not just a matter of how much orange tone is in it.
2. Copper is so much more noble than zinc that the way you must get zinc into the deposit is by complexing the copper, so adjusting the copper to zinc ratio in a deposit of brass involves a lot more than just the ratio of metal contents in solution. I don't think you'll get there with solutions based on "soda and water".

If you are doing individual pieces of art rather than attempting any sort of production plating, however, what might work is doing copper plating first, then zinc plating, and heating over a gas burner to cause diffusion. In this case I think (but I do not know) that by adjusting the thickness of the zinc plating layer and/or the heating time you may be able to adjust the color. There is a trick you can look up on the internet of zinc plating a copper coin, then heating it to get a gold color, and googling that subject may offer some clues. Good luck!

Regards,

Thank you Mr. Mooney,
I was about to change my route of thinking that way. Will try this one and will get back to you about the result for sure.

Regards,