|
SCRATCH
AND DENT
REPAIRS
Tool and Material Checklist:
- Wax and grease remover
- Dent puller
- Sandpaper assortment and sanding block
- Air filtering mask
- Body hammer
- Tack cloth and lint-free
- Multipurpose dolly
cloths
- Plastic spreader
- Glazing putty
- Body file
- Rubber contour squeegee
- Sanding board
- Body filler
- Safety glasses or goggles
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.
- Move the vehicle to a shaded area. Wash with
water and soap or mild detergent. Wipe dry with a
clean, lint-free cloth.
- Clean the repair area with a wax and grease
remover. This eliminates any built-up wax, grease,
road tar, etc., that could cause paint failure.
- If the car was polished with a silicone-based
cleanser, use a remover specifically designed to
take off silicones.
You're now ready to do the repair.
Repairing Scratches
- Lightly sand the scratches using 400-grit
paper to "rough up" the finish coat. Do not press
hard on the sandpaper; excessive pressure can result in low spots.
- Clean the area with a lint-free cloth and wipe
with a tack cloth.
- Apply a daub of glazing putty to the edge of a
clean rubber contour squeegee. Working with
small amounts, spread the putty using a fast scraping motion and moderate pressure in only one
direction, Never pass the squeegee over the same
area more than once.
- Allow the putty to dry completely before
sanding-preferably overnight.
- Wet sand the repair area with 400-grit paper.
Use a sanding block to avoid making low spots.
- Rinse the sanding dust away, wipe the
surface dry, and clean with a tack cloth. If additional applications of putty are needed, repeat the
above procedure as often as necessary.
- Use water, a sanding block, and 600-grit pa-
per to finish sand the puttied area. Sand with light
pressure and long strokes across the surface. Any
low spots must be filled with additional glazing
putty or body filler.
- When satisfied with the smoothness of the re-
pair, rinse away the sanding dust, wipe the
surface dry, and clean with a tack cloth.
- Spray a medium coat of finishing primer over
the repair area. Let dry about five minutes, then
wet sand with 600-grit paper. Repeat several times
until the repair area is glassy smooth. The surface
is now ready for painting.
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.
Bumping Dents
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:
- Off-dolly method. Press the dolly against a low
spot while striking an adjacent high spot with
the hammer. The hammer blow drives the high
spot down, while the rebounding dolly drives
the low spot up.
- On-dolly method. Place the dolly directly be-
hind the high spot. Press it against the metal
as hard as you can while striking the opposite
side with light hammer blows. This method is
used less frequently; the off-dolly method is
easier to do.
To bump a dent back into position:
- Make sure all dirt, undercoating, etc., has
been removed from the backside of the panel.
- Choose a surface of the dolly that best con-
forms to the contour of the panel, and match the
hammer face to the contour of the surface to be
struck.
- Use either the on- or off-dolly method to tap
the dent back into position, always bumping in the
opposite direction of the impact. First hammer
from the inside to achieve the rough contour. Then
switch the position of the hammer and dolly, and
hammer from the outside.
- Run your hand across the repair area to
check for any remaining high and low spots, and
carefully bump these areas flat.
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.
- Examine the area to determine the point and
angle of impact.
- Drill holes 1" apart along the length of the initial crease. Use a drill bit approximately one-half
the diameter of the screw at the tip of the dent
puller. NOTE: Always wear safety glasses or goggles
when drilling, grinding, or using any type of power
tool.
- Starting at the shallowest point and working
toward the deepest, insert the tip of the screw into
the first hole. Hold the handle of the dent puller in
one hand and forcefully slide the weight straight
back against the handle.
- Work out the crease slowly, in the opposite
direction of the initial impact. Pull out the first hole
slightly, go on to the next, and repeat the process.
- Work the surface as close to the original con-
tour as possible without pulling the metal beyond
the original surface. Any low spots can be filled
with body filler.
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:
| Temperature |
Working Time |
| 100°F |
3 to 4 minutes |
| 85°F |
4 to 5 minutes |
| 77°F |
6 to 7 minutes |
| 70°F |
8 to 9 minutes |
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.
Refinishing
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.
|