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Ted Mooney, P.E. RET
Pine Beach, NJ

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Painting anodized alloy wheels

Q. I have a set of forged alloy wheels for an MV Agusta. They have been anodized but I am not very impressed with the overall finish. Before I take them to the best paint shop in the area, is there anything that needs to be done to the anodized surface other than scotchbrighting, etc., prior to paint.
Many thanks H. Fabian

Harry Fabian
Bike enthusiast - Shrewsbury, United Kingdom
January 4, 2010

A. Forget scotchbrighting -- if wheels are clearcoated you can paint them directly. If anodized but not clearcoated or sealed you can paint them too. In any other case you must remove finish and then pretreat wheels with some conversion coating process (simple DIY process is 1 gm tannin/1 lit water). Hope it helps and good luck!

Goran Budija
- Zagreb,Croatia
January 12, 2010

Thanks for the reply Goran, I have yet to investigate further, but an MV Forum that I use did say that the wheels are anodised. What additional coating is on the anodizing I am unsure.

Harry Fabian [returning]
- Shrewsbury, United Kingdom
January 15, 2010

TUTORIAL FOR NEWBIES:

Aluminum may be protected from corrosion by anodizing, clear coating, or painting/powder coating.

Anodizing involves putting the aluminum into sulfuric acid with the work being anodic, to build a uniform layer of translucent aluminum oxide on the surface (there is a lot more to anodizing that that -- don't take this explanation as instructions). But aluminum is rarely pure; it is alloyed with copper, zinc, magnesium, silicon and other materials which do not anodize properly -- especially in the case of alloy wheels. Alloy wheels will not remain mirror bright when anodized, but will turn grey because of these other materials. This may be why Harry was not impressed with their finish.

Clear coatings can be of several different types including simple one-part air dry coatings, as well as the two-component clear coat usually used as the top layer on auto paint.

Should I anodize my alloy wheels?

Q. What about alloy wheels used on motorhomes? Is it wise to polish then clear anodize them with lasting results?

Dennis Finch
- TRAFFORD, Alabama, USA
March 13, 2014

A. Hi Dennis. We added your inquiry to a thread on a similar subject. If the wheels were machined out of billet aluminum (unusual today), the alloy might be of a type that anodizes well. But pressure cast aluminum alloy wheels have so much tramp ingredients, especially silicon, that I doubt that you will find their appearance after anodizing pleasing. I think you are better off clearcoating them.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2014

March 16, 2014

Thanks Ted. I am going to contact the wheel manufacturer and inquire about the alloy used in the wheels in question then, I'll post the details and ask for your comments once again.

These alloy wheels look very attractive when polished but, one dog on three legs makes a ... you get the idea.

Clear coat would work but I like to spend money (Heh-heh).

73 DF

Dennis Finch [returning]
- TRAFFORD, Alabama, USA

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