This method will be relevant when it is difficult to find a whole original spare part. The rusty fragment is completely removed from the wing, and the metal nearby is processed from corrosion. Using masking tape, the shape of the arch is restored, after which it must be covered with a layer of epoxy. Having strengthened the recreated part with fiberglass, you can begin to putty.
If all the foci of corrosion are eliminated and the epoxy is correctly applied as a result of such repair, the paintwork will serve for several more years.