SCRATCH AND DENT REPAIRS
Tool and Material Checklist:
Keeping up your cars appearance is important for more than just cosmetic reasons; it has practical value as well. It prevents general deterioration and large body shop bills. Even the smallest scratch or dent can turn into an unsightly defect and a costly repair if left untreated. By following the procedures in this booklet, you can repair mi- nor surface damage on your car quickly, easily, and with long-lasting results.
Cleaning: The Crucial First Step
Before starting, it is very important that the re- pair area is thoroughly cleaned.
You're now ready to do the repair.
NOTE: Always wear safety glasses or goggles and an air filtering mask when spraying primer or paint.
Repairing Stone Chips
Stone chips and nicks are repaired in the same manner as scratches, except that the damaged area must be sanded and primed before putty is applied. Rust formation must be inhibited with primer before finishing. Two types of primer are needed for this repair: zinc chromate primer for rust retardation and finishing primer for use as a final protective undercoating. A special air respirator is required when working with zinc chromate or similar primers.
A body, or dinging, hammer is used with a multipurpose dolly block to repair dents and creases. The hammer has two faces: one round for striking concave surfaces, the other flat for striking flat or high spots. The dolly block has several rounded surfaces that fit a variety of contours. The two methods of bumping dents are:
To bump a dent back into position:
Pulling Out Dents
When interior trim or body panels prevent access to the backside of the damaged panel, the hammer and dolly method is ineffective. In such cases, a dent puller must be used to pull the metal back into position.
Using Body Fillers
The key to successful dent repair is proper use of body filler. After a dent has been bumped or pulled close to its original condition, body filler is used to achieve the finished contour.
1. Sand the repair area with 36- or 80-grit paper on a disc sander or a wire brush attachment. For hard-to-reach or large areas, a paint stripper can be used. Remove approximately 4" of paint around the dent.
2. Featheredge the old finish, using 220-grit pa- per to rough up the metal.
3. Clean the sanded area, dry, then wipe with a tack cloth to remove all sanding dust.
4. Place the desired amount of resin on a mixing board. Knead the tube of hardener thoroughly, then squeeze a narrow ribbon across the glob of resin. This will give the correct proportion of resin to hardener.
5. Use a plastic spreader to mix the resin and hardener together with a firm, flat wiping motion. Do not stir; stirring will trap air in the filler and form pinholes.
6. The tiller will begin to harden after a few minutes. Use the following table to determine how much working time you will have:
7. Mix until the filler is a uniform color. Use the color guide on the package to judge the accuracy of the mixture. If it is too light, add more hardener; it it is too dark, add more resin.
8. Apply a thin tinning coat of filler over the re- pair area using a plastic spreader. Use moderate pressure to force out any air bubbles.
9. Apply the rest of the filler, working from the edges toward the center in smooth strokes. Build up the filler higher than the surrounding surface, but do not make any application thicker than 1/4'. Use a minimum number of strokes and work quick- ly, before the filler starts to set up.
10. When the filler becomes rubbery, use a 10" half-round 'cheese grater" body file to remove the high spots. Poll the file diagonally across the re- pair area and press lightly.
11. Allow the filler to harden (approximately 15 to 25 minutes). Use a sanding block and 50-grit paper to remove high spots.
12. Examine the filler. Do not be alarmed if low spots are found; even professional body technicians usually need more than one application before they are satisfied.
13. Apply as many coats of filler as needed to bring the level of the repair area above the surrounding metal, using the same procedure of applying, filling, and sanding.
14. With 50-grit paper and a sanding board, sand the final coat of filler to within 1/16" of the desired level.
15. Use 80-grit paper to sand the filler even with the original surface. Never trust your eyes when checking for evenness. The repair area should feel even. Keep in mind that paint does not hide imperfections, it highlights them.
16. When satisfied with the smoothness of the surface, clean with a tack cloth.
NOTE: Depending on the quality of the filler application, use either finishing primer or filler/finishing primer. If only minimal filling is necessary, use finishing primer; the filler/finishing type is best when imperfections in the filler must be hidden. Filler/finishing primer is also useful for filling low spots, hiding sandpaper scratches, and smoothing featheredges.
17. Before priming, do all necessary masking. Spray a light coat of primer over the filler and any metal surfaces.
18. When the primer has dried, any pinholes and scratches can be filled with glazing putty. Squeeze a small amount onto a clean plastic spreader and apply a thin covering over the filler.
19. Let dry, then wet sand the glazing with 240- grit paper and sanding block. Lightly sand until most of the glazing is gone.
20. Clean the repair area again with a tack cloth. Use additional putty to fill in any remaining imperfections. Your goal is a smooth, flawless surface; repeat as often as needed to achieve it.
21. Wet sand with 400-grit paper, using long strokes.
22. When satisfied with the smoothness of the surface, rinse and wipe dry. Use a tack cloth to remove any sanding dust that might have collected in pinholes, scratches, etc.
23. Spray the repair with finish primer, completely covering the filler, bare metal surfaces, and several inches of the old finish surrounding the repair.
24. Allow the primer to flash for five minutes, then wet sand lightly with 400-grit paper. Prime one or two more times, wet sanding after each application.
The dent has now been filled, glazed, primed, and sanded smooth, and is ready to be painted.
With the surface preparation satisfactorily completed, the refinishing job can take one of three forms: spot repair, panel repair, or overall repainting of the vehicle.
Spot and panel repair are small surface jobs where either an isolated spot or a complete panel are painted. Overall refinishing is just what it says-the entire vehicle is painted. Spot and panel repairs can be made with a spray can or spray gun; overall repainting must be done with a gun.