Refinishing motorcycle spokes?

A. Hello, Sachin.

Any steel over about Rc40 definitely requires embrittlement relief as soon as possible after plating (preferably within 2 hours, and definitely before lacquering). I don't know how hard motorcycle spokes are, but I'm confident they're not softer than that. Good luck.

Regards,

A. Dear Mr. Bhambure,

Studied your question about hydrogen de-embrittlement treatment for spokes of Motorcycles. Please note that it is very much required to subject spokes for hydrogen de embrittlement treatment since it is hard material. It is prudent to give hydrogen de embrittlement treatment before lacquer. Otherwise it will lose the aesthetic value.

A. I believe that even a clear chromate and topcoat can yield 125 hours to white rust, so any clearcoat at all ought to have no trouble passing in 125 hours. I don't know exactly what you mean by "automotive spokes", but if you mean spokes for automobile wheels, I don't think I'd knowingly buy any zinc plated ones :-)

A. Spokes for motorcycle wheel rims? You can try giving a coat of electrophoretic clear lacquer and cure with IR. But each spoke will have to be jigged!

A. Sunil ji,

The answer to your need is to use a topcoat sealant which is NOT a lacquer (hence not prohibitively costly). It will provide up to 125 hours after application and 24 hours of storage to allow the coat to cure.

Regards,

A. Hi. Although Mr. Nurie is extremely knowledgeable and has offered good advice as always, you are not restricted to topcoat sealants. Long ago I was with a supplier who led the transition from nickel-chrome plated bicycle rims & spokes to bright acid zinc plating of them -- and we definitely employed clear coats to get as close to the luster of nickel-chrome as we could :-)

Regards,

A. From your description, the spokes were probably zinc electroplated (not anodized; that is a process for aluminum). A job shop which does zinc plating can fix them for you, but it will probably cost more than simply buying new spokes. You should be careful using phosphoric acid on them. It can cause hydrogen embrittlement, and you could have a catastrophic failure at speed.

A. Hi, Tim. If the axles are hard steel, which I'd strongly suspect they are, they are very subject to hydrogen embrittlement. If they are soft steel, it is of no concern. Do you happen to have an idea of the hardness of this steel?

Regards,

A. Hi, Rob.

The temperature is 375° F. ± 25° F.; the minimum baking time after the parts have reached temperature is 3 hours, but could be as much as 24 hours for critical components. Letters 43822 and 14537 would probably be interesting to you.

We'd prefer to point you in general directions for study, and to try to answer specific limited questions rather than to say that such and such "is the process for treating/removing any H2 from a hardened steel part" because replies in a public forum are invariably highly abbreviated, lacking the important background info found in books and specifications, so it is dangerous to assume what a reader may and may not already know. Good luck.

Regards,

A. Hi Haroon. The proper procedure for spokes and their nipples is probably to acid zinc plate, hydrogen de-embrittle, and apply proprietary trivalent chromate conversion coating and topcoat as mentioned by Mr. Nurie. Please review the applicable chapters in the Metal Finishing Guidebook and get back to us with any specific questions. Best of luck.

Regards,