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world gathers for metal finishing
Q&As since 1989


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"Blisters" on Polished Aluminum car wheels

Is there a problem with brake dust, or something else, causing "blisters" on the polished aluminum wheels of cars, particularly the front wheels.
I am told, my car's wheels have no acrylic coating.

James Fox
consumer - Alexandria, Virginia
2003

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What "process" are you performing that you experience the blisters.

My (and many others I'm sure) experience is that a casting is a very porous substrate, particularly at the parting line and polished areas. This includes Aluminum, Steel and Zinc. The quality of the substrate is not metal dependent, but process dependent. An adequate "preheat" higher than cure temperature is usually used to purge any moisture out of the holes in the casting, but if the casting is of poor enough quality (which quite a few of them are) skim a little J-B Weld [affil links] or Bondo [affil links] Body Filler in the problem areas. It is my personal opinion that the weld and bondo route is unethical, but to get a part out the door it might do the trick.

I look forward to following opinions on this topic, because my 11 years in powder formulation and application has not prepared me for my last year coating zinc die castings.

Andy Peal
- Grand Rapids, Michigan, USA
2003

I am simply experiencing "blisters" on the inside of the polished aluminum wheels of my car from driving the car. I am told that this is not uncommon and may be caused by the brake dust. The manufacturer of the car "does not seem" to know of such a problem.

James Fox
Consumer - Alexandria, Virginia
2003