Acidic / Alkali Wheel Surface Damage

Non-acidic wheel cleaners

A moderate alkaline pH 10 is a safer alternative to an acid, be cognizant that a high alkaline pH 12+ can be as potent as an acid

Caustic sodium or potassium hydroxide both of which can be very aggressive alkaline. Basically it reacts with any oils/grease to make its own soap, so not only does it dissolve the oils/grease but the resulting soap adds to the efficiency of the cleaning system. That is the basis of alkaline cleaning.

Caustics react quite strongly with metals, and very notably with uncoated aluminium, which it actually dissolves quite rapidly. There is a higher level of alkalinity with caustics than non-caustics (it is about 2.5x for silicates). 

This has a very similar effects to strong acids; the potential for heavy corrosion as well as the clouding/dulling of the surface. Like the acids, these products need to be used with care on any sort of sensitive rim. Caustics are abundant because they are cheap and because the potential dangers are not made clear.

Acidic / Alkali Wheel Surface Damage

These chemical stains are frequently milky, black, or greenish in appearance. They result from using acid or high alkali content cleaning solutions, which may be exacerbated by using them on a hot surface or by allowing them to dry 

This type of surface damage usually entails refinishing. However the following product and procedure has been found in some cases, to improve the appearance of acid / alkali stained wheel surfaces; be cognizant that in some instances you may only achieve a < 50% improvement and in some more. For wheels that have milky or hazy staining caused by these types of chemicals try the following: Use caution with chrome wheel finishes as the plating is very thin and using harsh abrasives could remove it.

This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish.

The following product and procedure has been found in some cases, to improve the appearance of acid / alkali stained wheel surfaces. 

For wheels that have milky or hazy staining caused by these types of chemicals try the following:

1. Wash the wheels (See Note 1) thoroughly using clean water and soap or detergent and then flood rinse the wheel surface with clean flowing water.  

2. Dry the wheels completely.

3. Apply 3M Chrome and Metal Polish #39527 (See Note 2) with a clean terry cloth towel. As you apply the polish, the staining may diminish.

4. When dry, buff off the polish with a clean portion of the towel.

5. Repeat application of the Polish until satisfied with the results. If continued applications fail to improve the appearance further discontinue use (See Note 3).

This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. 

In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish.

Notes

1.      DO NOT attempt to clean hot wheels surfaces; allow cooling down time, otherwise you may cause structural damage to the wheels and cause the rotors and/or callipers to warp, making them inoperative

2.      THE 3M polish required for this procedure contains an extremely aggressive cleaner. The wheel surfaces must be clean prior to application to avoid scratches. This cleaner will reduce the coating thickness and if used incorrectly may remove the surface finish entirely.

3.      Begin with a small section of the wheel and with light pressure buff off polish and examine results. ONLY apply with sufficient pressure and time to remove enough staining that you are satisfied with the results. Some wheels may be stained to the extent that you may only achieve a < 50% improvement while others may be able to be restored to the original lustre. In all instances; only apply until the results are satisfactory.

Information Source:

GM Customer Service

I would like to think that these articles become an asset to anyone who is new to detailing and to professionals alike, as well as industry experts who seek to advance their knowledge.

I hope the above article was informative. By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire.

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