[Roadsters] Cleaning aluminum wheels

[JDF]

This describes aluminum oxide perfectly. Start with one of the 
"powerball" drill-type abrasive polish/wheel kits. If that doesn't work, 
move on to a real polishing pad (wool) and polishing compound or cutting 
compound. Cutting compound is pretty harsh and will swirl, you'll have 
to follow with lots of polishing compound. You'll have to figure out how 
to prevent the removal of the paint with a pad and polish (masking tape 
helps). The powerball wheel kits will probably leave the paint alone. 
There are metal polishes that will work well but they aren't doing 
anything different than the autobody compounds.

Aluminum oxide is one tough material and won't come off easy. It's much 
harder than the aluminum it came from so don't put a lot of pressure on 
a machine wheel or you'll dig out the aluminum and leave behind the 
aluminum oxide. Use time and patients with the machine. If the oxide is 
built up enough to catch a fingernail I might consider a light touch 
with a sanding disk with a super fine al-ox pad. You'll have to deal 
with the sanding damage to the polish with compounds and a wheel.

There's little that will prevent this other than a coat of oil or wax. 
The smooth surface of polished aluminum helps prevent oxidation by 
denying water a place to settle. Salts are a factor but not nearly as 
much as with steel rust. Both oil and wax won't stay on for long in the 
winter. A nice filthy coat of road grime and brake dust will help 
protect it though. I've always noticed that poorly cleaned wheels 
survive winter well. Anodizing is the usual solution for aluminum in 
harsh marine environments. Anodizing actually creates a fine layer of 
al-oxide and that allows the aluminum to hold paint or it can be tinted.

Automatic car washes that offer an extra wheel cleaning package will 
usually use hydrofluoric acid as the cleaner and that will greatly 
increase the odds of aluminum oxidizing. Hydrofluoric acid is a great 
cleaner (and deadly poisonous) but it strips all the oils off the 
aluminum leaving it vulnerable (not great for the steel in the wheel 
wells either). When I'm desperate enough to use an auto car wash I skip 
all the extras and get the basic wash and that usually means no 
hydrofluoric acid bath.



On 03/19/2012 06:43 PM, Dan Kroninger wrote:
> Hey list,
>
> I just removed the snow rims and tires from my daily driver the last weekend.
> I noticed that all 4 wheels have some sort of dirt or oxidation that I can't
> remove.
>
> It is white or grey in color and looks almost like lime or salt.  It presents
> itself as either blotches (bigger spots) or squiggly lines, almost like
> cracked glass.
>
> I first tried water and a soft cloth to remove it.  Then I went and got an
> aluminum wheel cleaner (meguires AL wheel cleaner). The guy at the store said
> to spray on and let sit for 30 seconds, then spray again and massage out the
> dirt with a soft tooth brush.  I used half a bottle on one wheel with zero
> effect.  Does anyone have suggestions?  They are just snow wheels, but I will
> be mounting a set of aluminum wheels on my roadster this summer and I don't
> want those wheels getting ugly.
>
> The snow wheels are polished aluminum rims with painted spokes.  They also are
> polished aluminum around the lugs.  The stain/dirt is only on the polished
> part.  I don't want to use anything to aggressive and buff up the rims.
>
> Any thoughts or suggestions would be greatly appreciated.  Also any thoughts
> on preventing this in the future?  The wheels are stored flat and stacked two
> high in plastic wheel bags.  Tires are mounted full time.
>
> Thanks,
> Dan
> Madison, WI
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