Repair of minor body damage (BMW 3 Series E46)

Restoration of minor car body scratches

1. If only the paintwork is scratched and the metal is not affected, it is very easy to remove the scratch. Lightly rub the scratch area with paint restorer or very fine sanding paste to remove a thin layer of paint and wax coating around the scratch. Rinse the treated area with clean water.

2. Apply a thin layer of liquid paint to the scratch with a soft brush: repeat this operation several times until the surface of the paint coating is leveled. Dry the new paint for at least two weeks, then polish the area with polishing paste, and then apply a protective wax coating.

3. If the scratch reaches the metal of the body, it may cause corrosion of the metal. Remove rust from the metal with a pocket knife, then apply an anti-corrosion coating to prevent corrosion in the future. Using a rubber or nylon spatula, fill the scratch with putty paste. If necessary, the paste can be diluted with solvent, which makes it possible to fill narrow scratches. Before the putty paste hardens, wrap your finger in a cotton cloth, moisten it with solvent, then quickly draw it across the scratch. This will slightly press the surface of the putty paste. Then the scratch can be painted over as described above.

Restoration of car body dents

4. In case of deep dents in the car body, the first task is to pull out the dent until the body has regained its original shape. Since it is unlikely that the dent will be completely straightened out, it is advisable to straighten the dent to a level that is approximately 3 mm below the level of the undamaged part of the part. If the dent is small, do not try to pull it out at all. If the dent can be accessed from the inside, it can be carefully straightened out with a hammer with a wooden or plastic head. During the straightening process, a suitable wooden block should be pressed from the outside to absorb the impact of the hammer blows, thus preventing the metal from bulging outward.



5. If the dent is in a part of the body that has double-layered metal or if access from the inside is impossible for some other reason, use a different technique. Drill several small-diameter holes in the damaged area, preferably in the deepest places. Then screw long self-tapping screws into the holes so that they hold firmly in the metal. Straighten the dent by pulling the screws out with pliers.

6. The next stage of restoration is to remove the paint from the damaged area and around it, approximately 2-3 cm. This can be done with a wire brush inserted into a drill or with sandpaper by hand. To finish preparing for filling, use a screwdriver to make grooves on the metal surface or drill small holes in the damaged area. This will ensure good adhesion of the filler paste to the metal.

7. The final repair operations are described below (see subparagraph "Puttying and painting").

Restoration of corrosion holes or deep damage to the body

8. Remove all paint from the surface to be restored and 2-3 centimeters around it using a wire brush inserted into a drill. If such tools are not available, this can be done manually using sandpaper. After removing the paint, it is necessary to assess the degree of corrosion and decide whether to replace the entire part (if possible) or repair the damaged area. New body parts are not as expensive as most car owners think, and replacing parts is often a quicker and easier solution than trying to repair a large area of rust.

9. Remove all parts installed in the damaged area except those that will be needed to form the original surface. Then use metal shears or a hacksaw blade to cut away all metal damaged by corrosion. To provide support when filling with putty, bend the edges of the hole inward with a hammer.



10. Use a wire brush to remove the powdered rust from the remaining metal. Apply a rust converter to the damaged area; if the inside of the rusty area is accessible, treat that as well.

11. Before you start filling the damaged area with putty, you need to cover the hole in some way. This can be done with an aluminum or plastic mesh, or aluminum foil.

12. For larger holes, it is best to use aluminum or plastic mesh or fiberglass. Cut a piece of material to approximately the size and shape of the hole, then place it in the hole so that the edges of the patch are below the level of the surrounding metal. Secure this position with a few drops of putty.

13. For small or very narrow holes, you can use aluminum foil. Unroll a piece of foil from a roll, cut it to approximately the shape of the hole, and glue it to the edges of the hole. If one layer is not thick enough, fold the foil into several layers. Rub the edges of the patch with a screwdriver handle so that they press better to the metal.

Body repair - puttying and painting

14. Before starting the work described in this paragraph, read the paragraphs describing the repair of dents, scratches and corrosion.

15. There are many types of putty fins, but the best are polymerizing compounds, which are sold in kits containing a jar of paste and a tube of hardener. You will also need a wide, flexible plastic or nylon spatula with smooth, well-processed edges for the final finishing of the putty surface.

16. Mix up a small amount of filler on a clean piece of cardboard or plywood, carefully following the proportions of paste and hardener according to the manufacturer's instructions, otherwise the filler will harden too quickly or never harden. Using a spatula, apply the filler to the area to be repaired and smooth it out to obtain the required surface. When the contour of the filled surface is close to the desired one, take a break from working, otherwise the filler already applied will begin to stick to the spatula. Continue adding thin layers of filler every twenty minutes until the filler level is level with the surrounding metal.



17. After the putty has hardened, its excess can be removed with a metal scraper or file. Further processing is carried out using sandpaper with gradually decreasing grain size: starting with class 40 paper and ending with waterproof class 4QD paper. Always wrap the sandpaper around a piece of flat rubber, cork, or a wooden block - otherwise the surface of the putty will not be smooth. In the process of smoothing the surface of the putty, the sandpaper should be periodically rinsed in water. Due to this, a smooth surface of the putty is ensured at the final stage of polishing.

18. At this stage, a ring of clean metal has formed around the "dent", which in turn is surrounded by good paint. Rinse the area to be restored with clean water to remove all sanding products.

19. Spray a thin layer of primer on the repaired area - it will show all the places where the putty surface has defects. Remove these defects with freshly prepared putty and sand again with sandpaper. Repeat this procedure until you are satisfied with the quality of the repaired surface. Rinse the surface with water and let it dry completely.

20. Now the area to be restored is ready for the final operation - painting. Spraying of paint should be done in a warm, dry, windless, but ventilated room. Such conditions can be created artificially if you have a large closed room. If you are forced to work outdoors, then you need to choose a suitable day for work. If you are working in a closed room, wet the floor in the painting area. This will help settle the dust that is in the atmosphere. If you are going to paint only one part of the body, cover the other parts; this will help reduce the contrast from slight differences in paint colors (chrome strips, door handles, etc.) should also be covered. For this, use adhesive tape and several layers of newspapers.



21. Before you start painting, shake the can well and try painting something away from the car until you get the hang of it. Cover the area to be repaired with a thick coat of primer; however, the thickness of the paint film should be created by applying several thin coats of paint, not one thick coat. Using 400-grade waterproof sandpaper, sand down any uneven areas of the primer. Keep the work area well wet while doing this, and rinse the sandpaper periodically. Allow the primer to dry before applying paint.

22. Apply a thin layer of paint with a spray gun, starting from the middle of the surface to be painted, and then smoothly move the stream from one edge to the other so as to capture approximately 50 mm of the surface with the old paint. After some time, apply the next layer. Create the required thickness of the paint layer by applying thin layers multiple times. Open the covered parts of the body approximately 10-15 minutes after applying the last layer.

23. After painting, the parts should be kept for at least two weeks, and then the painted area should be smoothed out using a grinding paste. After this, a protective wax coating should be applied.

Plastic parts

24. The use of more and more plastic body parts by car manufacturers (such as bumpers, spoilers, and in some cases, the main body panels), leads to the fact that in case of serious damage to such parts, it is necessary to entrust their repair to a specialist, or replace the parts. Repairing such damage on your own is usually not cost-effective due to the high cost of equipment and materials required to carry out such repairs. The basic technique for such repairs is to cut a groove along the crack line using an abrasive wheel inserted into an electric drill. After that, the groove is welded with a plastic rod melted with hot air. Then the excess plastic is removed and the surface is leveled. It is important to use a plastic rod of the same composition as the body part, since different types of plastic are used in the car (e.g. polycarbonate, ABS, polypropylene).



25. Restoration of damage of a less serious nature (scratches, minor cracks, etc) can be done independently using epoxy putty. This putty is used in a similar way for body repair. Usually the putty hardens within twenty to thirty minutes. After that, it can be sanded and painted.

26. If the part is being replaced entirely or if it is being repaired using epoxy filler, you may have difficulty finding a suitable paint that is compatible with the type of plastic being used. Until now, it has not been possible to use a universal paint due to the wide variety of plastics used in the manufacture of body components. Standard paints generally do not adhere well to plastic or rubber. However, it is now possible to purchase plastic body parts in a kit with a primer and paint in various colors. Detailed instructions are usually included with such a kit, but in general the method of use is to first apply the primer, then dry it for 30 minutes, and then apply the paint coating. The result is a correctly painted component, and the paint has good adhesion to the plastic or rubber (unlike standard paints, which do not provide such properties).

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