If the dent is very small, there is no point in straightening it out at all.
Caution: Hold a wooden block firmly against the back of the metal to absorb the hammer blows and prevent stretching of the metal.
If the dent is in a part of the body that has a double layer, or something else makes it impossible to access from the inside, a different procedure must be used.
1. Drill several small holes into the metal inside the damaged surface, preferably in the deepest parts.
2. Screw long, self-tapping screws into the holes until they engage firmly with the metal.
3. Now you can straighten the dent by pulling on the protruding screw heads with pliers.
4. The next stage of repair is removing paint from the damaged surface and from the surrounding metal by about 2.5 cm.
5. This is done with a wire brush or a sanding disc attached to a drill, but can be done just as effectively by hand with sandpaper.
6. To complete the preparation for puttying, clean the surface of the exposed metal with a screwdriver or file, or drill small holes in the damaged area.
7. This will ensure good adhesion between the metal and the glaze.
8. To complete the repair, see subsection 12.7.