Getting Personal With Powdercoat

Most hobbyists are familiar with the process of repainting a vehicle's exterior. In last month's issue of HPP, we heard a professional's opinion about the current trends and effects that modern technology has had on overall finish durability and the industry in general.

Best suited for components that are subjected to increased levels of heat or abuse, powdercoat is a highly durable product that's rapidly gaining in popularity within the automotive hobby. However, many hobbyists aren't acquainted with the colors presently available, the application process, or the benefits a powdercoated finish offers, so we contacted Josh Trail of Trail Performance Coating in Omaha, Nebraska, seeking a professional opinion. Here's what he has to say.

High Performance Pontiac: What do you feel has sparked the powdercoat popularity boom within the automotive hobby?
Josh Trail: When compared to conventional painting, powdercoating is generally cheaper and the finish doesn't shrink or check. It's also much more durable than paint. That's because the "powder," which is actually finely ground plastic, totally encases the component when melted and cured, resulting in a tough finish that's scratch and chip resistant. Unlike paint, which tends to harden as its solvent base dissipates, cured powder remains somewhat flexible, making it desirable in a wide range of applications.

Manufacturing companies and the aerospace industry have used powdercoat for quite some time, and its use has trickled into home life. We've powdercoated patio furniture, lawn and garden equipment, and even artwork for customers, but the majority of our jobs are automotive and motorcycle components. I believe much of that is due to its exposure in hobby-related television shows.

We're commonly coating suspension and underhood pieces in varying shades of black or cast-iron gray for local restoration shops, but we do many custom pieces, too. We're also coating lots of wheels-both steel and aluminum. We don't often receive requests to powdercoat body panels, however. Not only would panel preparation include metalwork without plastic fillers, the intense heat associated with the curing process might warp the metal.

HPP: Can you elaborate on the preparation, application, and clean-up processes?
JT: Powdercoating requires some specialized equipment. Compressed air is used to fluidize the powder, and air quality must be very high-it simply cannot contain any moisture. Like paint guns, the quality of a powdercoat gun is relative to its price, so you often get what you pay for. An open-ended paint booth with good lighting and positive ventilation is also required.

Any metal that can withstand a temperature of about 400 degrees F can be powdercoated, and surface preparation is a key element in the quality of the final finish. Some like using a chemical wash to clean the metal's surface, but I prefer mediablasting to promote maximum mechanical adhesion. If the powder doesn't adhere to the component well, it can lift, trapping moisture underneath, ultimately causing rust or corrosion to form.

After preparation, we hang the component in the paint booth and spray on a thorough coating of dry powder that's electrostatically charged. The piece is then baked at a temperature around 400 degrees F, which causes the powder to liquify and flow out uniformly.

Bake time varies on the type and thickness of the metal being coated-a 1/8-inch thick piece of aluminum may require 12 to 15 minutes, where a heavy cast-iron intake manifold may take 45 minutes to an hour to fully cure. There's some variance, but if the temp and time limits are grossly exceeded, gloss colors can dull while lighter hues can discolor. Under-cured powder is less adhesive and the overall finish is usually less durable.