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Chroming plastic and other non-conductive substrates

 

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Hi, Keith Burwell here with a polish and plating shop in Riverdale, GA. We do mostly bumpers and exterior automotive metal trim. We have recently been swamped with request for plating plastic and fiberglass automotive parts. I am familiar with the spray-on products that are offered through Alsa and Spectra, however I am interested in the copper nickel chrome plating process. Herein lays the problem: finding a copper base which will clean in Caustic soda and take a cyanide copper / copper strike. I have tried a couple of copper and nickel EMF (electro magnectic frequency) type "paints" to use as a base using ethanol to clean the part prior to plating. The copper paint produced great conductivity but unfortunately rubbed off as soon as my glove touched it. I know there is a process out there as I have seen the end results ...just can't find any information on it. Any help would be greatly appreciated.

Keith D. Burwell
polish and plating service - Riverdale, GA, USA

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Though most substrates can be plated, not every plastic or resin holds the plate well. It's a matter of adhesion. ABS was designed to provide the best attainable bond by means of a blend of three resins (Acrylic+Butadiene+Styrene) one of which (B) is in form of globules and dissolves during the pre-treatment leaving pockets that will act as counter-locks once the plate is built up. In any case, some sort of mechanical lock is always necessary when dealing with plastics because they do not have the bonding affinity to the plated metal that metallic substrates do. Look for Plating on Plastics or POP in this site.

Guillermo Marrufo
Monterrey, NL, Mexico

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Dear Mr. Burwell
Plating of fiberglass is much known in Egypt, but unfortunately preparation of substrate should start in molding stage not in plating shop.

You ask the factory to added some carbonate {CaCO3}

To the resin before molding then etched in any acid e.g. H2SO4 carbonate will dissolve and you get a good whole which is very important in providing the good adhesion the same role which butadiene play in ABS.
Kindly note the attached photo to one of our products made of fiberglass it is nearly in the same size of yours.

GOOD LUCK,

Raafat Albendary
- Cairo, EGYPT