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topic 713

Copper plating before nickel - chrome plating


(1998)

Hello,

In chrome plating bumpers, is there a difference with respect to appearance and/or corrosion resistance (in winter conditions) between the two following processes?

1) dull nickel, bright nickel, chrome

2) copper, dull nickel, bright nickel, chrome

If there is a difference, can the options be made equivalent by modifying the duration of the steps?

Patrick Turcotte
MultiPro - Canada


(1997)

There are still some people who believe that copper offers a better appearance for the best "show chrome".

I was at one O.E.M. bumper plating shop about 5 or 6 years ago that was still using copper for one automobile brand. But I've been to many others, before and since, and I think copper is a rarity for O.E.M.s these days. It's pretty much restricted to antique and show car enthusiasts.

Further, neither the MFSA quality guides (www.nasf.org), nor anything else I've stumbled on over the years, claims better corrosion resistance performance for copper.

I think the story is like this:

There was once a time, before bright self-leveling nickel, that copper was important because the bumpers would be copper plated, then buffed, before nickel and chrome plating. When self-leveling bright nickel became available, many shops still stuck with copper--not only out of familiarity, but because it allowed them to deal with old work per the old specs, and it allowed continued buffing of copper plate, which could be an easier way of dealing with minor scratches when refurbishing old bumpers than repolishing the stock. So copper plating stuck for much longer than the O.E.M. technology really required. But I wasn't elected keeper of the oral tradition, so if someone thinks I'm wrong, please speak up.

In terms of corrosion resistance, it seems that having the proper activity ratio between the bright and semi-bright nickel, so that pits grow laterally instead of penetrating, is the key. This is controlled with the STEP test. To improve corrosion resistance, some wheel platers do electroless nickel before the duplex nickel and chrome, but I'm personally not aware of any bumper platers that do it.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(1997)

Mr Mooney,

Thank you very much for your response, your insight is quite appreciated.

Patrick Turcotte
MultiPro - Canada


(1997)

I think Ted is right, copper is out. Double layer nickel gives a bright and ductile deposit. Sara

sara michaeli
sara michaeli signature 
Sara Michaeli
chemical process supplier
Tel-Aviv, Israel



While I think that copper is out, for the most part, on O.E.M. bumper plating, let me ask about aluminum wheels. I read that some quality wheel manufacturers are zincating and electroless nickel plating, then acid copper plating, baking, buffing, and nickel-chrome plating. My question would be why the copper plating? Per an article I read, it's for buffability. So my question would be, can you just duplex nickel plate the electroless nickel, or will it be too dull? -- or have some other undesirable characteristic?

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(1998)

I am a plater in a small job shop. We use a cyanide copper strike prior to bright nickel, chrome plate. In all the years I have found that the copper does help on corrosion resistance on plated parts in weather conditions. One thing I found is on any kind of exhaust pipe, (where heat is high), I skip the copper and go direct into bright nickel. I have never had the problem of blistering since I have practiced this process.

Does anyone have any pro's or con's on this?

Jim Coughlin


(1997)

We plate approximately 3000 O.E.M. Bumpers/day

I remember having many arguments with our long time managers over appearance of copper plated bumpers. They claimed that appearance-wise the copper added depth to the plate and used a simple reflectivity test of standing a ruler up against the bumper and seeing how far you could read its reflection. The results were in coppers favor but so slightly that it made little difference. Only the copper buffing helped to fill in any polishing lines.

If the steel is of good quality, flat polished properly and then polished and buffed before plate thoroughly you will wind up with the same results.

Corrosion wise a good STEP is the most important. Also a High sulfur barrier nickel is used between the semi and bright that helps considerably. Some platers tried putting a thin noble nickel layer over the bright (basically they ran their microporous nickel without any powder) which did affect corrosion sites but no one pursued this that I know of.

Mark Boscariol
plating shop - Toronto, Canada



April 2, 2012

HI
WE WANT MIRROR FINISH ON OUR PRODUCTS (WE ARE USING CRC SHEET) WITHOUT BUFFING, TO BE ECONOMICAL. PLEASE SUGGEST THE RIGHT PROCESS.
CURRENTLY WE ARE DOING BUFFING AND CLEANING LINE AND THEN NICKEL. BUT STILL AFTER GIVING HALF AN HOUR IN NI BATH WE ARE NOT SATISFIED WITH QUALITY. LONING MARKS ARE STILL THERE.
WE ARE USING COPPER WIRE RATHER THAN JIGS.
LOOKING FORWARD FOR A POSITIVE REPLY.
REGARDS

ABHISHEK GOEL
METAL INDUSTRY - LUDHIANA, PUNJAB, INDIA<

April 5, 2012

Hi Abhishek.

Are you using proprietary nickel plating processes? If not, what are you using as a leveler? This sounds like just a single layer of bright nickel. I think you'd probably get a better product from a self-leveling semibright nickel plating process followed by bright nickel.

I don't think the copper wire in lieu of jigs is relevant to this problem though. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



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