How to repair holes in thresholds quickly and cheaply without welding

To repair leaky, rotten sills in an old car without welding, you can use fiberglass. When impregnated with resin, it will become very rigid and will be able to completely cover existing through defects in the body.

Materials:

fiberglass;
polyester resin Novol PLUS 720;
starting putty with fiberglass;
finishing putty;
anti-gravel;
primer paint, varnish.

The process of repairing rotten thresholds

The area of the threshold damaged by rot is cleaned with a grinder with a petal wheel.

Since the metal near the holes has become thinner, it needs to be stiffened. To do this, you need to bend it inward with light blows of a hammer. This will also provide the necessary space for gluing the fiberglass.

Cut the fiberglass into strips to fit the hole, with a small margin. Then the stripped metal is smeared with resin mixed with a hardener, and a flap is glued on top. It is also impregnated with polyester. After the first layer has set, the next piece of fiberglass is applied.

Having made the casing from fiberglass, it needs to be sanded a little with a grinder with a flap disk to create roughness.Putty with fiberglass is applied on top of the filled holes. It is placed with a reserve to remove all differences.

After setting, the putty is sanded with coarse sandpaper.

The remaining defects are sealed with finishing or universal putty.

Next, sanding is done with P80 sandpaper and a block. This way you can get a smooth surface better than using a sander. The finishing layer is sanded with a fine sandpaper.

Having achieved a smooth surface, anti-gravel is applied. Due to its roughness, it will perfectly hide minor defects that remain due to poor sanding of the putty.

Next, the color is painted to match and varnish is applied.

Such repairs are not comparable to replacing thresholds, but they are inexpensive and can be done on your own in the garage. If you then fill the thresholds with cannon fat, the effect will last for more than one year, even when storing the car outside.