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How do I make sure my wheels don’t prematurely corrode after getting them refinished?
One contributing factor to premature corrosion is excessive shot size used in coating removal. When shot larger than S330 (see TMC RP 240A), peaks and valleys on the wheel surface can result. These peaks and valleys cause irregular mil thickness of the final coating and can allow the rust to enter into the surface and spread across the wheel.
It is important to understand that how your wheels are stripped of coating will affect how well your new coating will adhere, determining how well your wheels will resist rusting. It will also affect the structural integrity of the wheel’s surface, directly affecting your wheel’s safety.
Do I need to have a primer used in refinishing my wheels?
Depending on the weather and road conditions your wheels endure, using a primer on your wheels may be a good option. Fleets that encounter rough winters, and thereby endure the road salts and chemicals spread on driving surfaces, often need more protection on the surface of their wheels. By using a zinc-rich primer, you can provide additional protection against inset corrosion that can’t be eliminated through any coating removal. This will mean the finish on your wheels will look better for a longer period of time, saving you time and money in frequent refinishing.
What is the finished MIL thickness of the powder coat process?
According to TMC RP 240, your wheels should have a finished mil thickness of no more than 3.5 mils on the mounting surface. This can be tested by using a mil thickness gauge mid-way between the bolt holes along the mounting area, on both sides of the wheel. It’s also important to avoid any runs or excessive coatings, as this could cause the joint to settle in and lead to loose fasteners, premature wear, or even the loss of a wheel. Your service provider should check the powder coating thickness of each wheel it refinishes.
How do I know my finished wheels are completely cured?
Once your wheels are blasted and powder coated, they should be processed through an oven to fully cure. Your service provider should check the cure of your powder coat by using a methyl ethyl ketone (MEK) and Q-Tip rub test. If the coating fails this rub test, it most likely did not have enough time in the oven to allow for curing and should be re-serviced. If your wheels are not completely cured, they are prone to premature corrosion.
What’s the difference between using paint or powder coating with my wheels?
Painting is a low-cost and well-known method for coating your wheels, but in reality, it leaves your wheels vulnerable to corrosion. Prone to scratching and chipping, paint is a short-term solution, causing unnecessary corrosion to your wheels and leading your vehicle to be taken off the road again and again to get its wheels repainted. Painting also does not shield the wheel from long-term exposure.
Powder coating is a process that uses advanced technology to create a more durable finish. The wheel’s prepared surface is sprayed with powder coating, essentially color and resin particles that have been electrostatically charged. Because of their positive charge, they adhere to every part of the wheel’s surface without running, pooling, or distributing unevenly.
This method of coating allows for a stronger coat than painting, meaning more protection for the wheel, and less wasted product.
When curing, the coating is then set by exposure to high temperatures. The powder melts, flows evenly over the surface, and chemically reacts over the surface of the wheel to create a tough, web-like interlocking of molecules. This molecular structure does more than cover your wheel – it defends it.
Special note: when considering having your wheels powder coated, make sure you use a powder that is engineered for refinished steel truck wheels.
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