Minor Body Damage Repair

Minor Scratch Repair

If the scratch is superficial and does not penetrate to the body metal, the repair is very simple. Lightly rub the scratched surface with a fine polishing compound to remove loose paint and wax. Rinse the surface with clean water.

Apply touch-up paint to the scratch using a small brush. Continue to apply thin coats of paint until the scratch is completely filled. Allow the new paint to dry for at least two weeks, then blend it with the surrounding paint by polishing the painted area with a fine polishing compound. Finally, apply a top coat of wax to the scratched surface.

If the scratch has penetrated the paint and damaged the body metal, causing rust, a different repair procedure is required. Remove the rust from the base of the scratch using a pocket knife, then apply anti-corrosion primer to prevent rust from forming in the future. Using a rubber or nylon applicator, coat the scratched area with glaze (glaze is a semi-transparent paint layer).

Before the glaze in the scratch hardens, wrap a piece of smooth cotton cloth around the tip of your finger. Dip the cloth in thinner, then quickly wipe it around the scratch surface. This will help ensure that the glaze surface is slightly recessed. Now the scratch can be painted as described earlier in this section.

* If necessary, mix the glaze with thinner to make a very thin filler, which is ideal for filling narrow scratches.

Dent Repair

When repairing a dent, the first step is to pull the dent out so that the damaged area is as close as possible to its original shape. There is no point in trying to fully restore the original shape, because the metal in the damaged area has stretched and cannot be returned to its original contour. It is best to level the dent so that its depth is approximately 3 mm below the level of the surrounding metal.

If the dent is very shallow, there is no need to pull it out at all.

* Hold a wooden block firmly against the back side of the metal to absorb hammer blows and prevent the metal from stretching.

If the dent is located in a section of the body that has a double layer, or anything else makes access from the inside impossible, a different procedure must be used. Drill several small holes in the metal inside the damaged surface, mainly in the deepest parts. Screw long, self-tapping screws into the holes so that they engage firmly with the metal. The dent can now be pulled out by pulling on the protruding screw heads with pliers. The next step is to remove paint from the damaged surface and from the surrounding metal for approximately 2.5 cm. This is done with a wire brush or a grinding disc fitted to a drill; however, it can be done equally effectively by hand using sandpaper. To complete the preparation for filler, scrape the exposed metal surface with a screwdriver or file, or drill small holes in the damaged area. This ensures good adhesion of the metal and glaze. To complete the repair, refer to the subsection on filling and painting later in this chapter.

Repair of Rust Holes or Cracks

Remove all paint from the damaged surface and from the surrounding metal within a radius of approximately 2.5 cm, using sandpaper or a wire brush fitted to a drill. If these are not available, this work can be done by hand using several sheets of sandpaper.

After removing the paint, you can determine the extent of corrosion and decide whether to replace the entire panel or, if possible, repair the damaged area. New body panels are not as expensive as many people think, and it is very often much faster to install a new panel than to repair a large area damaged by rust.

Remove all trim parts from the damaged area, except those that serve as a guide for the original shape of the damaged body, such as the headlamp housing, and so on. Using metal snips or a hacksaw blade, cut away all damaged metal as well as any other metal showing signs of rust. Use a hammer to bend the edges of the hole inward to create a small recess for the filler material.

Use a wire brush to clean the damaged surface and remove powdery rust from the metal surface. If the back of the rusted surface is accessible, coat it with anti-corrosion primer.

Before final filling, close the hole by some method. This can be done using sheet metal riveted or screwed over the hole, or by installing wire mesh in the hole.

Once the hole is closed, the damaged area can be filled and painted.

Filling and Painting

Currently, a large number of body filler products are available. However, a body repair kit containing filler paste and a tube of polymer hardener is generally the best choice for repair work. You will need a wide, flexible plastic or nylon spreader to level the surface of the filler. Mix a small amount of filler on a clean wooden board or piece of cardboard, using hardener sparingly. Follow the manufacturer's instructions on the package, otherwise the filler will not harden properly.

Using the spreader, apply the filler paste to the prepared surface. Draw the spreader across the surface of the filler to achieve the desired contour and level the filler surface. Once the original level and contour have been achieved, stop working the paste. If you continue, the paste will stick to the spreader. Continue applying thin layers of paste at 20-minute intervals until the filler level exactly matches the level of the surrounding metal.

Once the filler has hardened, remove any excess with a file. Then use sandpaper, gradually increasing the grit, starting with 180-grit paper and finishing with 600-grit waterproof paper. Always wrap sandpaper around a rubber or wooden block, otherwise the filler surface will not be completely flat. While sanding the filler surface, periodically wet the 600-grit waterproof sandpaper with water. This will help achieve a very smooth surface.

The repair area must now be surrounded by a ring of bare metal, which in turn must be surrounded by good, undamaged paint. Rinse the repair area with water until all sanding dust has been removed.

Apply a thin coat of primer to the entire sanded surface. This will help reveal any defects in the filler surface. Correct any defects found with fresh filler or glazing compound, and sand the surface again with sandpaper. Repeat the priming and filling procedure until you are satisfied with the quality of the filler surface and the paint edge. Rinse the surface with clean water and allow it to dry completely.

The repair area is now ready for painting. Spray painting must be carried out in warm, dry, windless weather, when there is no dust in the air. These conditions can be achieved if you have access to a large workshop. However, if you have to work outdoors, choose the painting day very carefully.

If you are working indoors, spray water on the floor. This will help settle dust that could otherwise rise into the air. If the repair area is on a single body panel, mask all surrounding panels. This will help minimize slight paint color mismatch. Trim and decorative parts, such as chrome moldings, door handles, and so on, must also be masked or removed. Use masking tape and several layers of paper for masking.

Before spraying, shake the paint thoroughly, then practice spraying to learn the correct technique. Apply a thick coat of primer to the area being repaired. It is better to apply several thin coats than one thick coat. Using 600-grit sandpaper, sand the primer surface until it is very smooth. During this operation, the surface being worked must be thoroughly wetted with water. Periodically dip the sandpaper in water as well. Allow the primer to dry before applying additional coats.

Spray the paint onto the top coat, building up thickness by applying several coats. Begin spraying from the center of the repair area, then, using circular movements, cover the entire repair area and approximately 5 cm of the surrounding paint. Remove all masking material 10–15 minutes after applying the last coat of paint. Allow the new paint to dry for at least two weeks, then use a very fine polishing compound to blend the new paint into the original paint so that the transition is invisible. Finally, apply a coat of wax.