There are only a few places on the continent where steel wheels and rims are not subjected to an environment that causes rust to form on the surface. Even in those rare instances where the natural operating conditions are conducive to preserving the original finish for years, the normal wear and tear in a commercial operation is going to eventually expose bare metal, which leads to corrosion. Over the past decade, the tire industry has introduced a number of approaches to improve the appearance of steel wheels and rims — with widely varying results.
Nothing is more frustrating than spending thousands of dollars to refinish steel wheels only to watch the rust come back after just a few months. Truth is, there are a lot of different processes and methods for applying a finish, so choosing the right vendor is definitely the most important step. Before you spend a dime, someone from your company should inspect the facility and determine if it's a quality wheel and rim refinisher.
The cleanliness of the wheel or rim has a major impact on the effectiveness of the coating. A shot blast cabinet is typically used to remove the old finish, but the media (shot) should be finer than bird shot, yet a full step above sandblasting. Ultimately, the goal is remove the old finish without displacing or damaging the metal. If the original manufacturer stamps on the rim are still visible after shot blasting, the media is probably the right size. If the stamps are pulverized or etched away, it's either too large or too fine.
It's also important to take note of how the wheels are handled after leaving the shot cabinet. Since oil on technicians' hands can have an effect on the performance of the coating, clean gloves should always be worn when handling bare wheels. Once the previous finish is removed, the rim should never contact the floor and the new coating should be applied as soon as possible.
When it comes to the finish, there are paints and powder coats. Paints are exactly that, so adequate drying time is necessary. And runs are always a possibility. All it takes is one drip on the mounting surface to lose a wheel, so make sure your technicians pay attention to the process of applying the paint around the bolt holes. Powder coat uses an electrostatic charge to adhere the finish to the wheel after it has been baked in an oven, but it's still possible to apply too much or too little. Regardless of the type of coating that is applied, it should be no more than 3.5 mils thick after it has fully cured.
If your prospective wheel or rim refinisher has no method for measuring the thickness of the finish, you might want to find someplace else. Likewise, if the coating is so thick that the original manufacturer stamps cannot be read, quality control is definitely an issue. Few people can consistently distinguish between 3.5 mils and 4.0 mils with the naked eye, so the vendor better be able to measure the thickness and check it as part of standard operating procedure.
Refinishing steel wheels and rims can be an expensive proposition. The advantages are primarily cosmetic since the structural integrity or effectiveness of the wheel or rim is not affected by surface corrosion — except on the mounting or mating surfaces. But the idea of having nice looking wheels on all your equipment can quickly turn into a nightmare if the vendor is not paying attention to the details.