ABS lips suck, buy a new one. Honestly, the time i spent trying to repair my lip was not worth it. I used abs cement, epoxy, fiberglass resin, patched fiberglass to the back. Obviously, i wouldn't have tried all this if any actually worked. I was using color matched spray cans at the time for $20 a pop, plus time and effort with cheaper materials. It would look good for a few months and crack in the corners. I finally broke it bottoming out and it was almost uplifting.