Metal finishing Q&As since 1989

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Comparison of plastic chroming techniques

I apologize if this has been asked numerous times, but I was unable to find a similar post using a search. I have some abs injection molded parts that require a chrome finish. I would like a brief comparison of the vacuum metallization process with a immersion process. Is it true that an immersion process will produce a thicker, more durable finish than metallization? Also, I am under the impression that it is possible to Nickel plate platic. Is this correct? Thanks very much for any help.

Dave Riess

2006

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Hello Dave. It all depends on the parts, their aesthetic requirements, and the service condition, but there are probably at least three approaches to bright plastic parts, to wit, chrome-like paint, vacuum metallizing, and nickel-chrome plating.

chrome-look paint has advanced greatly in the last few years and some people are using it on exterior parts, but not at the OEM level to my knowledge. Vacuum metallizing consists of vacuum depositing aluminum on the article and then covering it with a protective clear topcoat. Nickel-chrome plating consists of etching the plastic, dipping it in a conductive seed of palladium chloride, then autocatalyticly plating it, followed by copper, nickel, and chrome plating. Real nickel-chrome plating is what you see on virtually all exterior automotive brightwork.

Being originally from the plating industry, I am accustomed to saying that nickel-chrome plating is what you see on an auto grill, and vacuum metallizing is what you see on a boy's plastic model of the car :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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First of two simultaneous responses --

Vacuum metallizing is also found on cars. It is applied on the reflecting surfaces of plastic head and tail lights and other commercial lamps. It is not as resistant as copper-nickel-chrome plating but is the preferred method when there will be little or no exposure to abrasion or handling.

Guillermo Marrufo

2006

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Second of two simultaneous responses --

Besides three methods mentioned by Ted, a fourth method of vacuum metallizing plastics, ceramics or fiberglass with chrome has been developed and is on its way to the market. It is similar to vacuum metallizing with Al. As for the Al, to my knowledge, most of the auto head lights/tail lights and flash light reflectors are now vacuum aluminized. This will allow you to compare the difference in color and appeal. Aluminum is used bcause it has the highest visible light reflectivity (>95%) while chrome is only about 70% reflective.

Mandar Sunthankar

2006