I had an old 4 inch wide and about six inch long "flap" torn out of our All-Trac front bumper, done by the previous owner. It had about 1/4-1/2" gap in the tear, it would not lay flat and was real obvious. You could open the flap and see right through the bumper to the ground. Unfortunately I did not get a good "before" picture of the damage.
I took a wire bush to the inside of the tear, and sand paper to the outside face of the bumper, and cleaned it good with solvent. I mixed the two part mixture on a scrap of wood with the supplied squeegee tool. I filled both sides of the tear and taped it down flat. After it cured I removed the tape and rough sanded the outside to contour. I than mixed up a bit more to fill the low spots and blend in any unevenness at the repair spot. Once it cured I sanded it all smooth and even with the bumper.
Now it almost looks like there was never any damage to the bumper at all. only a slight color difference can be seen in the picture, and that could be evened out with tire-black or black paint. The repair filler can also be painted according to the package. It is a great product and easy to use.

repair mix tube

contents of kit

repaired bumper, damage was right at corner (under the red stripe)

front view of repaired area