A step-by-step guide for cleaning and polishing aluminum rims.
By Mark Quasius, F333630
Aluminum alloy wheel rims offer a number of advantages over steel rims and are a popular choice on many motorhomes. First, they look cool. They also contribute to ride quality, because they are truer than steel rims; they are lighter; and they won’t bounce as much from inertia, meaning the tires will remain in contact with the road. It is also easier to gain access to the valve stems without cutting your hands on stainless-steel trim rings. Oh, and did I mention that they look cool?
The downside is that aluminum rims don’t remain shiny forever. The constant abrasion from swirling dust, the effects of road salt and tar, and oxidation eventually will tarnish their brilliance. Fortunately, uncoated aluminum rims are thick and the shine can be restored to them by polishing, which is really a method of super-fine sanding. Rims that have been exposed to the elements over time take on a chalky appearance, and if the oxidation continues, pits will develop on the surface. The only way to get rid of this pitting is to remove the top layer of aluminum. A polishing compound that’s designed for alloy metals will eliminate the haze and pits by removing the surface layer of the aluminum to expose the fresh metal underneath. An abrasive polish will quickly remove the top layer but won’t leave a very fine finish. A polish that is too fine will leave a nice, shiny finish, but it will take a lot of time and hard work to achieve the desired result.
So, it’s important to find a good aluminum wheel polish that achieves the right balance between fine and abrasive. A number of products on the market are designed for this application, and just like vehicle waxes, everyone has a preference as to which one works best. In this article, we won’t attempt to evaluate the effectiveness of these various polishes. No matter which one you choose, the polishing procedure remains the same.
The first step is to determine whether your aluminum rims are coated or uncoated. Some rims are available with a clear coating that acts as a sealer to protect them from oxidation. Coated rims should never be polished and must be lightly washed with soap and water. If you use anything abrasive on them, the clear coat will become scratched and look foggy.
While the clear coat helps to maintain a consistent sheen, the coating tends to dull the original shine of the aluminum. So, uncoated rims look great when polished and bad when they are neglected; clear-coated rims may never look great but will always look good.
The two most common brands of clear-coated wheels are the Alcoa Dura-Bright and Accuride Accu-Shield. Before you begin, check for stampings or decals that identify them. If you cannot determine whether the wheels are coated or uncoated, you must test them before beginning the polishing procedure. Apply a tiny amount of the polish on a paper towel and rub it onto a small area by hand. The towel should turn black as the polish reacts with the aluminum. If the polish doesn’t turn black, you have coated wheels and they should not be polished. For proper cleaning instructions for coated wheels, refer to the Web site links at the end of this article.
Begin by washing your wheels with mild soap and water to remove any dirt or grease buildup. Do not neglect this step, because if you polish dirty wheels without first washing them, you’ll grind the dirt into the aluminum and leave deep scratches. Once you have washed the rims and dried them with a towel, it’s time to start polishing.
The process involves applying a small amount of polish to the wheel rim and working it in. The polish will remove the top layer of haze and pitted aluminum. The deeper the pits, the more polishing will be required, because you are actually removing material from the rim to expose the fresh aluminum beneath the damaged surface. When applying the polish, it’s a waste to use microfiber cloths. The cloth will turn black quickly as the polish reacts with the aluminum. Instead, use heavy-duty paper towels and dispose of them as they become dirty. If the wheel rims have suffered serious damage or neglect, you may want to use a more aggressive product when you start. You can try super-fine steel wool or one of the finer 3M Scotch-Brite? pads to remove heavy oxidation or stains prior to the finish polishing.
Foam applicators such as Mothers PowerBall? or Meguiar’s Brilliant Solutions Wheel Polishing Kit with the DynaCone polisher will help speed up the process. These foam polishers attach to an electric drill and help make the polishing process less strenuous. You can use a cordless drill, but I’ve found that even when using an 18-volt cordless drill, battery life will not be sufficient, and extra batteries or a corded drill will be needed to finish the job.
The PowerBall is available in two sizes: a 5-inch-diameter standard size and the 3-inch PowerBall Mini. The standard size works great for doing the majority of the wheel rim surface, but the smaller version comes with a 10-inch-long extension shank and is perfect for getting into tight areas and the small, round vent holes in the rims. You really need both to do the job right. The DynaCone? has a tapered design that is suited for typical spoke wheels found on passenger vehicles. It doesn’t handle the large rim areas found on motorhome wheels as well, but it is a great combination tool for reaching tight spots.
Begin by applying the polish to the applicator. With the power off, use the applicator tool to spread it around a small area of the wheel. Start by using a slow drill speed to prevent slinging the polish, and then increase the speed up to 300 to 400 rpm to polish the rim. Don’t try to do a large area all at once. The polish lasts only a short time until it turns black as it removes the aluminum. Take a towel and wipe off the old polish while it is still wet. Continue around the rim in layers as needed until the desired results are achieved. Once you are finished, apply one last layer of polish by hand to give it the final luster. At that point, wipe everything down with a dry towel and, finally, a wet towel to remove any polish that remains in the pores of the rim. A finishing rinse with Meguiar’s Final Inspection spray ensures that every last bit of polish is removed.
Frequent application of polish will make the job much easier and prevent deep pits and hazing. If you do a quick hand-polishing job after your RV has been washed, you won’t have to go through the extensive polishing that will be required should you neglect the rims. This assures that your wheels will remain shiny and will make your RV look more attractive.
Sources And References
Alcoa Wheel Products