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topic 38227

Cleaning milky stain from Aluminum wheels



A discussion started in 2005 & continuing through 2017

(2005)

Q. Restoring a set of Aluminum Alloy wheels, the OEM clear-coat didn't do its' job protecting the aluminum. I've stripped the clear-coat off the wheels with Airplane Remover, buffed hard with steel-wool, Mother's Aluminum polish, Soft-Scrub, but large white-ish/milky blemishes remain. The wheels are machined & have circular groves (like an old record album) so can't sand the wheel. I used an acid based wheel cleaner (hydrofluoric, sulfuric, nitric, phosphoric) which really brightens the entire surface, even the blemishes. Even buffed this solution with steel wool (I wore gloves, goggles and stood up-wind if you're interested in my health). But the blemish remains. Was thinking about hydrochloric acid bath, but concerned this may turn the aluminum to a gray/black tarnish & therefore not help. These blemishes are very noticeable at 6 ft, but not bad at 20 ft.

Bob Elmore
consumer - Cary, North Carolina


(2005)

Aircraft Stripper

A. Since my question never got posted here I performed this on my own, though I'm no expert so your experience may vary.

Restoring stained aluminum wheels (take all safety precautions seriously):
Clean entire wheel to remove grease/grime.
Remove the clearcoat with a metal safe cleaner (Airplane Remover). My wheels had a chemical stain on the aluminum which penetrated the clearcoat while leaving the clearcoat in-tact.
Spray Hydrochloric acid (HCl) to coat the wheel surface (Muriatic Acid 20% HCl). Keep it wet until blemishes are removed and the level of gray desired is achieved (10 minutes to remove stains & another 30 minutes to gray the aluminum).
The aluminum became a cloudy/textured gray.
Use a mag wheel cleaner (hydrofluoric, sulfuric, phosphoric, nitric acids) to polish areas where I wanted to accent the aluminum.
Painted inset sections and clearcoated the entire wheel surface.
I am pleased with the results.

Bob Elmore
consumer - Cary, North Carolina

----
Ed. note: Sorry for the delay, Bob. The problem you were trying to solve is now posted above your answer.


July 19, 2017

Q. Isn't this in fact removing the anodizing, and leaving the aluminum much more vulnerable to oxidation and staining?
I've never found a way to brighten milky, anodized aluminum without removing the anodized layer, and once that's gone, the surface is much softer and more vulnerable. Waxes and sealers will normally only keep it looking good for no more than a month or so. Two-part clear-coat will provide some protection for about a year on wheels and other parts that see rough use.
If I'm missing something on this subject, please enlighten me. I'd love to be wrong about this, but I've never found a non-destructive solution to milky anodizing.

Jeff Knox
- Buckeye, Arizona, USA



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