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Water soluble lacquer in lieu of copper electroplating?

We are currently spraying conductive silver coating on ABS/Nylon articles and then electroplating a thick copper for very good brightness as well as polishing on the copper where necessary. Subsequently we are depositing about 20 microns of 24k cyanide gold, i.e. about 1 gm on every article of 25 to 30 cm2 surface area. The current production is 100 pieces per day.

I want to become environment friendly and would like to do as follows:
Spray a water soluble lacquer. Coat a thin film of copper in a vacuum chamber. Plate non cyanide gold.
The quantity expected per day is 1000 pieces equivalent to 1 kg of gold per day.

Can anybody help ?

Shishir Neatia
- Mumbai, India
1998

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Hi, Shishir. Frankly, it's a little annoying when people say they want to stop plating so they can become environmentally friendly -- without specifying what they feel the environmental problem to be. It tars my whole industry as being polluters, making it sound as if it is so obvious that we pollute that there isn't even a need to file a bill of particulars :-)

That being said, though, I would have to agree that if the reason you are plating a heavy layer of copper is solely so that you can buff it back to a smooth surface, then you would be better off applying a smoothing layer of water-based lacquer instead, and then applying just a very thin layer of copper instead of a thick one. However, while special solvent -based lacquers have been used for this smoothing function, I'm not confident that it can be done with water-based materials. Your first need may be for development effort rather than production equipment.

I'm surprised that you haven't had trouble with putting gold directly onto copper, because they tend to diffuse into each other over time, and some people would use a barrier layer of nickel (or nickel substitute) between the copper and the gold.

Can you not go a step further and evaporate gold directly onto the lacquer, skipping the copper? I think some people put titanium nitride under the gold so that a good color is maintained when the gold wears through. But if you want to electroplate the gold, yes, cyanide-free gold is available from many suppliers.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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My name is Quan Nguyen, a manufacturing engineer at Omohundro Co. At Omohundro, we are making radome for various aerospace companies. Currently, we are making a radome called BAT. The BAT needs to be plated with electroless copper, electrolytic copper, low stress electrolytic nickel, and electrolytic gold. The process is time consuming and very costly. Therefore, we are trying to find a better alternative. We are thinking of using a good conductive coating to reduce the cost and plating time. We appreciate if you could give us some suggestions on the types of conductive coating or a better alternative to the method than we are currently using. Sincerely yours

Quan Nguyen
Omohundro Company - Costa Mesa, California
1999

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I don't know the required properties of those radomes, so I don't know what to suggest. But it should be possible to electroless nickel plate the item and perhaps replace 3 steps with one. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999