Re: 3M Marine High Strength Repair Filler
Yes, 3M makes good products, but I can't see filling a 3 inch by 5 inch hole without using some glass if you expect there to be any strength. I once upon a time filled holes about that size with bondo on a fender and it did not last long! Perhaps a screw hole, but not a big opening like 3X5. I think one good kick and it will pop out or at least crack.