Resto-Mod Restorations: Part 7 - Bodywork
The bodywork involved in our Resto-Mod restorations includes hammer and dolly use, dent and ding repairs with plastic and fiberglass fillers, some body panel alignments and fitting and the application of prime coats. Keep in mind that our approach to all these topics is from the do-it-yourselfer's point of view, rather than that of the classic car coachbuilder. Jeff Noll and Jim Mokwa built beautiful, trophy-winning-quality Resto-Mods. Jeff's car was recently invited to be exhibited at the Milwaukee Auto Show-an honor extended to very few Resto-Mods. But these cars aren't going to the Pebble Beach Concours d' Elegance to be judged.
Hammer and Dolly Use
An auto body dolly is a heavy piece of rounded, wedge-shaped metal used in conjunction with a body hammer or slapping spoon to smooth out dents, bumps or other imperfections in automotive grade sheet metal. Like a blacksmith's anvil, the auto body dolly is used as a smooth surface against which a car's sheet metal is pounded to take out surface imperfections. You hold the dolly against the back of the metal while you're hammering on the other side of it.
The hammer can be used to either strike directly on the spot that the dolly is held under or to strike off to one side of that spot, depending on how you want to shape the metal between the two tools. While you might think the hammer does the smoothening, but it is actually the rebound action of the dolly, after you strike on it with the hammer, that does most of the metal smoothening work.
These two tools play into a Resto-Mod restoration in different ways. The hammer and dolly can smooth out a previously damaged door skin like the one that Jeff Noll found on the driver's side of his car. You'll remember that Jeff pulled the door skin back into its shape with the spot-weld puller tool he borrowed from Bruce Young. Jeff then wanted to make the Camaro's door look as smooth as new. From his friend, he learned it was bad practice to use a thick coat of filler to recreate the correct fender shape, since a thick coat of filler can crack. A better option is to hammer and dolly the fender until it is brought back quite close to the original shape and then use just a thin "skim" coat of filler to finish the repair.
A hammer and dolly can also be used to achieve proper alignment of the sheet metal parts. Jim Mokwa told us that getting correct panel fits prior to painting was the most important part of the bodywork done on his GTO. If you try to bend or fit a panel after paint is applied, you will damage the paintwork. Jim and his body shop man, Leo, completely assembled the body of the GTO on the frame before attempting to use primer. This allowed them to check door alignment, etc. Only after they were totally satisfied with the panel fits, did they again disassemble the car and remove the body from the frame for painting.
The force and accuracy of the body man's hammer blows is important. You should start by using the flat side of the hammer head on flat and convex metal surfaces; then use the curved face side on concave surfaces. Do not try to fix a curved surface with a flat dolly, since this technique will never work.
When you want to use the "hammer-on-dolly" method, bring the hammer down directly on the spot behind which you are holding the dolly. By using a part of the dolly that closely matches a panel's original shape, you will push the panel back into that shape. When you bring the hammer down with a proper light to medium blow, it will make the dolly rebound and push the metal higher from underneath. The metal area immediately below the hammer strike will rise up.
When you use what is called a "hammer-off-dolly technique,' the dolly is placed to the side of the spot where the hammer hits. This will push the metal under the location of hammerhead contact down, while the metal off to the side, above the dolly, will be pushed up. By using light blows and moving the positions of the two tools, you'll be able to "work" high and low spots out of the body panel.
Dent and Ding Repairs With Plastic/Fiberglass Fillers
Dent repair involves reworking the damaged area until the correct contour of the metal has been generally restored, then applying very light coats of plastic body filler to smooth out the low spots. If you have room to get a dolly behind a dent, you can restore the basic shape by using a hammer and dolly. Or, if you need to spread out the down-force for a big dent, you can substuture a "slapping spoon" for the hammer. The spoon is simply a kind of flat hammer. If you can't get your body tools behind the dent, you can use a puller such as Jeff used to fix his door. Or another possibility for small, soft dents on a panel without any creases is to use a suction cup tool that seals to the door and has a pull handle.
After you have reworked the dent (or other irregularities) using one of hammer-and-dolly techniques, the next step in the repair process is to apply your body filler to bring any low spots up to the level of the surrounding metal.