How to Restore Aluminum-Magnesium Wheels

A wheel with a true single-stage acrylic enamel that they used from the factory is not manufactured any more. Thus, making wheel restoration an important process. They do manufacture single-stage polyurethanes but that’s not how they came from the factory originally. They came from the factory as a single-stage acrylic enamel with no clear coat.

Zinc chromate is available and is used as an adhesion promoter for aluminum/magnesium alloys. However, a zinc chromate primer is a single stage with no hardeners and stays soft. I’ve found that by using an aircraft allodine wash and etch to enhance my adhesion, works better than using a zinc chromate primer. I always use a two-part material with a hardener to ensure durability and longevity. By using the Allodine wash there is absolutely no build up of adhesion materials such as zinc chromate and I can go directly to a very light coat of a chromate primer then go to my two-part epoxy primers for my filler properties. You need the filler properties in order to fill imperfections after media blasting your wheels. Zinc chromate is not to be used as a filler primer but only for adhesion purposes.

Products change in the automotive refinishing business because of AQMD requirements. In the 1960s and ’70s, zinc chromate was the best available for adhesion on aluminum/magnesium alloy. In the zinc chromate primers it’s the chromate that helps with the adhesion process not so much zinc. Nowadays they have chromate primers without using the zinc properties.

Since they don’t manufacture straight or acrylic enamel material any more you can achieve a single stage by asking your painter to add a little flattener agent in the clear. Also, if your painter is using a solvent base coat have him mix in a little base coat with the clear coat as well. This will achieve a single-stage enamel look.

Another way to do the wheels if you want to use a single stage process and not use a clear coat, is to use a single-stage urethane color and simply add flattener to achieve a medium gloss, single-stage enamel look.

For the complete two-stage process please read my tips and tricks to restoring Aluminum/Magnesium wheels.