It's only after the hard work is done that we can get down to business and lay down the color. As can be seen by the various bodywork stories elsewhere in this issue, our project '76 Stingray has a long way to go before the overall finish can be applied to the highly modified body tub. However, our paint plan has always been to spray the removable panels individually and off the car, allowing full coverage of the edges and jambs without seams when the car is reassembled. This is a common technique in painting top-level show cars, but taking this approach comes with its own set of cautions. The most important consideration here is to end up with a perfect color match from panel to panel. To make this happen, two main factors come into play: the paint and the application.
The removable panels of our...
The removable panels of our Corvette project will be painted separately from the main body, which means they must be racked in the booth for spraying. We disassembled the interior of our T-top panels and the edge trim and masked them appropriately to prevent the paint overspray from getting to the backs of the panels.
First, let's consider the paint. For the panels to match, the paint must be a perfect match. If more than one batch of mixed color is involved, it always pays to "bulk" all the paint together, mixing the batches together. Once this is done, all the paint becomes one batch of the same mix, and we're ensured that all the panels will be painted with the same color base stock.
The application is the second factor, and this is a little more difficult to define. One of the key variables is the type of paint itself. If the color coats include effects like pearls or candies, or heavy metallic, getting a consistent look becomes more difficult, or even impossible, depending upon the effect. Even regular metallics can be difficult, but there are ways to minimize the potential for mismatches, such as using a consistent number of coats, and finishing with a fogged mist-coat technique.
Fortunately for us, the paint we are using for our Corvette project, Planet Color Chumma Orange, is a solid orange. This is the least-sensitive color to match in terms of application technique. A solid (color) works well when painting panels individually, with little chance of a mismatch, so long as the coverage is complete and sufficient to hide the primer. Our painting strategy is to paint the hood, doors, headlamp assemblies, roof panels, and miscellaneous small parts first; then paint the main body. Painting the car in pieces provides complete coverage of the edges, hood gutters, and jambs, for a seamless look.
A clean surface is most vital...
A clean surface is most vital just before the final paint spraying. Begin cleaning with a dust-down with compressed air, followed by a solvent cleaning with wax and grease removal solvent. We used Sherwin Williams' R7K158 Ultra Clean here.
Three Steps To Color
Before the actual paint is applied, the spraying begins with a preliminary step, the sealer coat, which is an extra primer coat. Sealer helps fill and smooth minute sanding scratches, and it gives a consistent surface for the color basecoat, improving uniformity. Primer sealers are designed to go on smoothly and are made to allow spraying the topcoats directly on top, with no prior sanding. Usually, the color basecoat is applied just after the solvents are allowed to flash from the applied sealer coat, in a matter of minutes.
It's a good idea to use a sealer coat that is reasonably close to the color of the topcoat--orange in the case of our Corvette. Sherwin Williams' sealer system comes in a full range of colors, and here we used the available red and yellow to mix an orange primer. By mixing an orange tinted sealer the base color coat will be able to "color-up" or hide the primer much more easily.
The finish we're using is a basecoat/clearcoat system. This is the most popular technique in auto refinishing these days and includes the basecoat, which gives the finish all of its color properties but none of the shine and durability, and the clear, which provides both of these properties. Once the sealer coat has been allowed to flash dry and is inspected for flaws, the basecoat application can begin. If the sealer coat is rough or problems are found, it's best to stop and fix the problem or start again, rather than continuing with the paint. Small dust nibs or other minor flaws can usually be lightly sanded off once the sealer has sufficiently dried.