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Paint & Body
24 Key Paint & Body Tips
These Secrets Straight From the Pros will Save you Time and Money on your Next Paint and Body Project
Sep 2, 2011
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Hamilton, OH 45015
Dooley & Sons Rods & Customs
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24 Key Paint & Body Tips
With most muscle cars now approaching 50 years of age, you never quite know what you’re going to get until you take them apart. Pulling the door panels off this ’64 Impala revealed that the original metal had been hacked up to install a power window kit. Since the Impala’s doors were already painted, and new replacements cost $350 each, Jeff Cameron bought a set of rusty used doors for $50 a piece. Although the door shells on the replacements were rusted, the insides of the doors were still solid. As such, the insides of the replacements were cut out and welded into the original doors. Not only were the used doors cheaper than new replacements, but this trick helped save loads of money on repainting the doors, and the hassle of trying to match the color to the rest of the car.
A quality paintjob often requires completely stripping a car down, but sometimes it’s nearly impossible to get interior trim pieces to fit back in the same way they came out. Items like door panels often attach with a combination of clips and screws. Cameron recommends using an ice pick to help line up the panel to the screw holes before re-attaching the clips. Afterward, the panel can be screwed into place.
For full-frame cars like Tri-Fives and Chevelles built with road course use in mind, Cameron highly recommends replacing the factory rubber body mounts with solid aluminum units. Although ride quality will take a hit, since even full-frame cars tend to flex quite a bit, it’s imperative to make the chassis as solid as possible. Otherwise, the suspension simply can’t perform properly.
Using a chassis jig ensures that the body is completely level and straight before welding up the body panels. When new quarters and tail panels were installed on this Camaro, Cameron noticed that the left rear framerail was 3/4 inch lower than the right side. This allowed straightening the frame before attaching the rest of the body panels, and attempting to line them up in vain. According to Cameron, if a panel is just 1/8-inch off in the front of the car, it can be as much as 5 inches off by the time you get to the back of the car.
Many hot rodders recognize the benefits of lining the floorboards with Dynamat, but how about the roof? Cameron says doing so cuts down on wind and road noise dramatically. Many ’50s cars like Tri-Fives had a paper-based product on roof liner from the factory, and it must be scraped off before laying down Dynamat. Taking things one step further, a Dynaliner foam product measuring 1/2-inch thick can also be sprayed on top of the Dynamat in the headliner. The process is so effective that Cameron often performs it on late-models as well.
To set this first-gen Camaro apart from the pack, the fresh air vent was removed from the cowl and replaced with a custom 16-gauge metal plate. Since the front leading edge of the cowl panel is curved, it’s more effective to use a shrink-stretcher instead of metal brake. Even for a skilled fabricator, making a panel like this takes a full day of work.
When installing new lower quarter-panels, the easy way out is overlapping the panels instead of butt-welding them together. However, this requires using a lot of body filler, and moisture tends to collect in the overlapped section and cause rust. To avoid this, Cameron prefers butt-welding the panels together using a TIG machine. He says, “You weld a little, hammer dolly the metal, then let it cool off before moving onto the next section. It’s a long, drawn-out process that takes two to three days on each side of the car, but once we’re done, it looks like it’s a factory-original quarter.”
Tight panel gaps distinguish pro bodywork from hack jobs. Cameron suggests using a nickel to help gauge panel gaps, and fills them in with metal and filler rod as opposed to body filler. The door-to-quarter-panel gap is notoriously large whenever using replacement quarters. In bare metal, Cameron shoots for a 3/16-inch gap, which provide clearance for paint and primer. Once the panels have been painted, the gap closes up even more.
One of the most overlooked yet most difficult pieces of sheetmetal to replace is the taillight panel. Once set in position, it must be clamped at multiple points to keep it straight while welding. Before any welding takes place, however, new edges must be fabricated around the taillight section to tie it into the quarters. That’s because replacement quarter-panels are straight and don’t include a metal edge that wraps around the taillights.
Even if they’re old and rusty, you may want to reconsider chucking the factory trunk hinges in the trash. Typically, removing the surface rust from old hinges and spraying them with a fresh coat of paint makes them look as good as new.
A big fuel pump that hangs beneath the bumper might be OK in a drag car, but can ruin the rear profile of a Pro Touring machine. To help tuck the fuel tank and pump closer to the body, the trunk floor on this Camaro has been raised several inches. This required building a custom trunk pan, which took between 7-10 days.
Flat-sided cars like Tri-Fives and Chevy IIs make poor bodywork look even worse. A common rookie mistake is relying too heavily on body filler. This makes it very difficult to straighten out the panels, and once painted, the result is wavy-looking paint. Likewise, body panels should be blocked with all the sheetmetal attached on the car. If the panels are blocked individually on a stand, too much material will be removed from the edges of the panel, where they will curve inward.
Prepping bumpers for chroming is like prepping body panels for paint. If the bumpers aren’t completely smooth in bare metal, they’ll look even worse once chromed. Chrome that lacks sufficient nickel content will start looking dull in a short period of time.
Media blasting a car always reveals its ugly secrets. When rust holes are filled with body filler, they’ll eventually sink into the body panel and create a low spot. The proper fix is to fill in the holes with metal so only a very thin layer of Bondo is required.
Smoothing the firewall can yield a clean, modern-looking engine compartment, but there are certainly some pitfalls to avoid. Someone has attempted, unsuccessfully, to smooth out the outside perimeter of the firewall on this ’57 Chevy. In situations like this, Cameron says that it’s easier to replace the entire firewall with a custom unit instead of trying to fix prior mistakes one section at a time. When doing this, it’s imperative to reinforce the body with X-braces under the dash and in the doorjambs to prevent the car from flexing.
Cars like the ’57 Chevy have studded trim pieces that run the entire length of the quarter-panel. They attach with nuts on the back side of the panel, and over-tightening them can put waves in the paint and destroy the panel. Furthermore, sealer should be used around each nut to keep moisture from penetrating into the quarter-panels.
There’s no way around the fact that poor metalwork results in poor bodywork. The rockers on this Tri-Five have already been replaced before in a prior repair, and now the filler is falling apart. The reason is because the pinholes in the welds were not ground flat, so the body filler never adhered to the metal properly. Consequently, over time pinholes in the welds resulted in pinholes in the body filler.
When inspecting body panels, the condition of the inside of the panel is just as important as the outside of the panel. Although this Tri-Five fender has some surface rust and Bondo, overall it’s in good shape and its inner structure is very solid. At times it doesn’t always make sense to salvage an original body panel from a cost standpoint, according to Cameron, it’s often worth the effort.
Cars might roll into the paint booth in fully assembled form on TV, but that’s not how things work in real life at high-end body shops. After assembling all the body panels and block-sanding them, the paint should be applied only after all the body panels have been taken back apart. This enables getting paint evenly into all the nooks and crannies like the doorjambs.
Fiberglass cars like C1 Corvettes are completely different animals from steel-bodied machines. Since they’re more prone to flexing and cracking, they must be supported on special fixtures with additional reinforcements all around the body. Although there are cheaper alternatives on the market, Cameron prefers quality brand paint guns that can cost up to $700 each. According to Cameron, cheap paint guns might work well if you’re lucky, but sometimes they won’t spray anything at all. Generally, primer guns have bigger nozzles than paint guns, and sealer guns fall somewhere in-between. CHP
Fiberglass bodies are particularly susceptible to pinhole formation. It takes patience and a trained eye to sand all the pinholes out, especially in the doorjambs and trunk. Using a Scotch-Brite pad is a no-no.
Granted, some backyard hot rodders can get surprisingly good results from painting cars in their garage, there’s a reason why shops spend tens of thousands of dollars on paint booths. Not only do they filter out dust and assorted contaminants, they also supply a steady stream of air to prevent blisters from forming in the paint. The painter’s suit and mask has its own separate air supply.
Paint guns are powered by compressed air, so it’s very important to remove water from a paint booth’s air supply. Dooley’s facility features two separate water traps, a primary trap near the air compressor and a finer secondary water trap inside the paint booth.
Although there are cheaper alternatives on the market, Cameron prefers quality brand paint guns that can cost up to $700 each. According to Cameron, cheap paint guns might work well if you’re lucky, but sometimes they won’t spray anything at all. Generally, primer guns have bigger nozzles than paint guns, and sealer guns fall somewhere in-between. CHP
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