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  for Metal Finishing since 1989
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Motorcycle parts rechroming

2003

Hi,

I've recently had some motorcycle parts rechromed. On close inspection of the mudguards it seems that there is some bubbles under the plating on the inside of the guards. These can be depressed with a finger. The external of the guards appears fine. What could have caused this? Is it poor surface preparation or some other cause? Also when I was tighten up one of the rechromed screws some of the chroming chipped off to reveal the nickel plating underneath. Again what could have caused this? Before I go back to the plater I'd like to understand what the problems are.

Thanks,

Mike Luscombe
- London, United Kingdom

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Hi, Mike.

If the parts are blistered they will peel shortly, and that area has an unsatisfactory decorative finish. What actually chipped is probably the nickel and chrome plating, not just the chrome, because chrome thicknesses are in the millionths of an inch (you would hardly see them). If you are quite sure you see nickel plating underneath, it could be delamination of a new nickel layer from an old nickel layer that was left on there.

To tell you all of the factors that can contribute to blistering would fill a book, and you really don't want to acquire years of plating experience to negotiate with the vendor over this fender, but for a quick tutorial of what chrome plating is about, you may want to see our FAQ, "Introduction to Chrome Plating". Plating should not peel, and blistered plating will peel and is unacceptable. However, it is also true that nickel-chrome plating is a decorative finish that is applied to visible surfaces, rather than an entire part (look at the backside of a truck bumper or old car bumper for example--there is no decorative value given or expected). So whether you can expect decorative value on the inside of a mudguard is a question which unfortunately probably should have been discussed and resolved before the plating was contracted, because you may have expected a decorative finish on the inside and the plater may have not even considered trying for one. Good luck!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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