My salvaged 2275 had a tree fall on it. Apart from upholstery rips it cracked the plastic seat structure. I tried patching it with a car fiberglass repair kit but after two days of drying, the fiberglass just peeled off. Any suggestions on how to repair this myself? - don't suggest dealer. I'll just rivet it to a steel frame if need be. These are pics taken from the inside of the seat.