Clean the metal around the holes and treat the surface with rust Converter. Take fiber, cut out three patches, the first should be 2-3 inches more than the size of the hole, and each of the next patch to be 5-6 inches more than the previous.
Epoxy glue from all sides saturate the fiberglass and attach to the back of the body. Glue these patches, starting with the smallest. Wait for complete drying of each layer. After grind, primer, putty, painting of the body from the outside. But the result of this method is short-lived and suitable for holes of small size.
Fill the hole some other way. Treat the area of the repaired body surface as in the first case. Cut-out metal piece that needs to be more holes on the 25-30миллиметров. Apply the patch and the body a thin layer of tin to protect the metal from rust (make tinning). Powerful soldering iron, attach a piece of metal on the back side of the body. Then thoroughly rinse the surface.
Remove the bulge of the metal resulting from heating. This light blows of a wooden hammer to push it. The resulting dent is repaired by a thin layer of putty. Finish off the surface with coarse sandpaper. Degrease the work surface with white spirit, apply primer (to prevent corrosion) of several types and in several layers. Let dry completely for 3-4 hours. Then calmly sand and paint.
Note that all the proposed methods are good for patching small corrosion holes that are on the wing of the car, on the doors, hood and rocker panels. If rust has formed on the vehicle chassis, without welding will not do. We are talking about the security of your life.