Technology has brought a number of durable finishes to the hobby. In "Exterior Finish Education" (HPP, June '08), a professional shared his opinion of the products and trends commonly used in modern restorations. We followed that with "Getting Personal with Powdercoat" (HPP, July '08), which explored the powdercoating process and the durable finish it produces. We learned that powdercoat's high degree of visual appeal and low maintenance qualities make it suitable for components that live in harsh, but relatively low-temperature, environments.
While gathering information about powdercoat, Josh Trail, of Trail Performance Coatings in Omaha, Nebraska, informed us that ceramic coat is another highly-durable finish designed to endure extreme temperatures. He's intimately familiar with its application process and explained that, while many hobbyists believe the finish is similar to powdercoat, the two have little in common. The application processes differ greatly as well. We then asked Trail if he could provide us with a better understanding about ceramic-coating. Here's what he had to say.
High Performance Pontiac: Can you explain what ceramic coat is?
Josh Trail: Ceramic-coating was initially developed for the aerospace industry and, like powdercoat, it found its way into the automotive hobby. It's essentially a high-solid paint product that's concentrated with ceramic powder and provides a durable finish that reduces heat transfer when cured. It also inhibits corrosion and makes metals last longer, resists most stains, and is impervious to oil and fuel. In fact, very little sticks to it.
HPP: Can you explain the ceramic-coat application process?
JT: Applying ceramic coat is similar to applying paint onto a body panel. A high-volume paint gun is required and the compressed air used to atomize the product must be very clean. A paint booth with good lighting and adequate ventilation is also required, along with a certain degree of temperature and humidity control within the shop. There are a number of physical steps involved with the application as well.
We begin by baking the component in the oven for a cycle to rid it of any impurities and burn off any old paint or grease. Once it's cool, we media-blast the piece with aluminum oxide-we prefer it to other types because it leaves no residue behind, thereby producing an overall cleaner finish. The piece is then handled with gloves from that point forward to prevent metal contamination and promote maximum adhesion.
Just before applying the ceramic, we typically preheat the piece to 100 degrees F, causing the ceramic to flash as it hits the warm metal, drawing the heavy moisture out of the coating, and helping to prevent runs. We place the freshly coated piece in the oven and allow the finish to cure for 2 hours at 500 degrees F. With most colors, the part is ready to use once it cools to room temperature.
HPP: What colors are available?
JT: Though powdercoat is offered in a wide array of colors, most ceramics are single-stage and available only in a satin finish. We suggest using ceramic over powder when the working temperature of a component exceeds about 250 degrees F. Ceramic color choice is ultimately limited to the intended operating temperature of the component.
Silver ceramic contains a significant amount of aluminum powder, which gives the finish an attractive high-gloss appearance once it's polished. Since the finish can safely withstand temperatures up to around 1,200 degrees F, it's commonly used to coat tubular headers and exhaust system components, but the aluminum can permanently discolor if that temperature is grossly exceeded.
While the temperature limit of most other colors is less than silver ceramic, black and cast-iron gray are safe up to around 2,200 degrees F. Clear ceramic is also available, but isn't presently designed for high-temperature applications. It's more commonly used as a topcoat on modern exterior finishes of high-end late-model vehicles or as an anti-graffiti coating.
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