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topic 54501

Bad chrome plating from China




March 3, 2010

I and many others have imported Chang Jiang motorcycles (replicas of a 1937 BMW) from China. The chrome parts pit and rust in less then 6 months. This occurs on imported VW bug parts as well from J.C. Whitney. I assumed this was because the steel parts are polished and then plated with chrome only (no nickel). After reading information on this site it seems that a part must be plated with nickel before chrome. If so, what makes these parts rust so quickly? Or is my original thought valid, chrome on steel only.

Richard Hahn
restore bikes and cars - Westbury, New York


March 3, 2010

Hi, Richard. Nickel-chrome plating is a premium finish if applied as a premium finish. If applied poorly (with a very thin single coat of nickel), then it's a horrible finish -- worse than no finish at all.

Here's why: While some metals like zinc are anodic to steel, and offer sacrificial protection, nickel is cathodic to steel. That means if there is a tiny pore in the plating, the steel will corrode to try to sacrificially protect the nickel. Every tiny point of porosity will quickly become a rapidly growing rust bloom and pit.

I had a Huffy bicycle with chrome plated fenders that rusted horribly in weeks, so I know how worthless and disgusting low quality nickel-chrome plating can be.

When done right, nickel-chrome plating is glorious and highly corrosion resistant. So don't give up on nickel-chrome plating . . . swear off of vendors with zero pride in workmanship.

Regards,

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


March 4, 2010

Just to follow up on what Ted has said. Nickel-Chrome plating, if well done, can be very durable. Just look around at all the truck bumpers which are 10+ years old and still in fine condition.

Almost certainly what you are getting is a very thin single layer of nickel overplated with chrome. Single layer nickel *might* be acceptable if sufficiently thick, say .0015" minimum, and assuming all else is well with adhesion and porosity.

Much better would be duplex nickel with .0007" of semi-bright nickel overplated with .0003" bright nickel and finally plated with microcracked chrome. You would then have a product which would last, and of which you could be proud.

Most of the nickel chrome plating coming from China is done on low price, with no specifications given or enforced, and is therefore garbage.

You will get nothing better than what you specify and inspect for. If you require nothing but low price, you will get what you have asked for.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina



March 1, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. As a guitar player and custom guitar builder, I am curious to know what types of finishes might provide superior corrosion resistance against human contact, perspiration, and ambient temperature changes. The chrome plating commonly used on most guitar hardware parts is prone to rusting. The plating is applied typically over die-cast metal, soft stamped sheet steel, and brass. If I had a solid lead on what type of finish would provide superior corrosion resistance than chrome, I would pursue having some sample parts prepared and do some testing. I can typically make chrome-plated parts begin to pit or rust in about 2 months of once-a-week playing for a two-hour session. The most devastating failure is corrosion that eats through the chrome plating and makes the die-cast metal begin to deteriorate. Only by diligent wiping immediately after playing with a clean dry cloth, can corrosion be mitigated. It is not always possible to do this, and then the guitar gets stored all sweaty in its case, which doesn't breathe, and then the problems set in. I would love to be able to offer superior protection to hardware to customers, as I doubt I am the only player with sweaty hands that has problems with rusting hardware. Because I am currently low-volume, I classified this post as Amateur, however, I could envision a scenario where volume of merchandise would move to the Industrial range.

Doug Hunt
- Hartford City, Indiana, USA


March 1, 2012

A. Hi Doug.

There is nickel-chrome plating and then there is nickel-chrome plating. Perhaps more so than any other finish, the quality of chrome plating can range from superbly protective to amazingly destructive...I'll explain why:

Some platings like zinc are cathodic or sacrificial to steel. This means if the plating is porous or perforated, they still protect the steel; the zinc forms a battery with the steel, causing an electrical current to flow such that the zinc corrodes and forces the steel to not corrode. Other coatings like paint or powder coatings are electrically neutral; if there is porosity or a scratch, the steel will corrode as if it were unpainted. But nickel-chrome plating is anodic to the underlying steel; if there is any porosity, the battery formed between the plating and the steel forces the steel to corrode to protect the plating. The "battery" formed between nickel-chrome and zinc diecastings is even worse; the diecasting will erupt into tiny craters in its effort to keep the nickel from corroding

So if there is any porosity, nickel-chrome plating is a horrible finish. But if the nickel-chrome plating is done right, with no porosity, a truck bumper can easily last a couple of decades with no corrosion at all in extremely corrosive ambient conditions.

If you want to investigate other platings for any reason, that's fine . . . but I'm confident that really high quality nickel-chrome plating that lasts decades on a truck bumper out on the road will last many years on a guitar. Good luck.

Regards,

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


March 5, 2012

A. A final note.

The original question was about chrome plating on Chinese made motorcycles.

Much of the chrome plating I have seen coming out of the Orient is garbage, although I must admit, there are some platers in the USA who produce garbage too. Unfortunately that lousy plating makes folks sometimes think that chrome plating is inherently a poor finish. That is simply not true.

I think Ted described well done chrome plating as a *glorious* finish, and I agree. Nothing else is as bright, slick and reflective, and it is a finish which can last, literally, for decades.

To see what good chrome plating looks and lasts like, just look at any Harley-Davidson motorcycle manufactured in the last ten or fifteen years. H-D does not do their own chrome plating. It is done for them by several job shop platers. Why is it so good? It's because H-D specifies it that way - thicknesses, appearance, and freedom from visual defects and demands that their platers meet the specifications.

Good chrome plating is never cheap, but

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg,
      South Carolina


April 17, 2012

A. You might look for a local plater and consult them for re-plating the affected parts. We have a couple good ones here in the DC / Baltimore area. Ask for a "triple" plate (copper / nickel / chrome). As stated above you get what you pay for. Good quality plating will cost a bit, but will definitely look fantastic. As a Harley Rider I can attest to the sentiments of chrome being "glorious". NOTHING looks as good as top-notch chrome, nor looks as bad a poor quality chrome.

Pete Cardona
- Hollywood, Maryland, USA



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