 If your putting in a hatch or making modifications to your kayak, keep your offcuts in a bag somewhere, why? because so far its very difficult for me to get coloured plastic welding rods and patch material |  The two deep gouges on this hull needed filling and because the customer bought his offcuts in I could use those and fill the gouges up. |
I made this picture bigger so you could see the final result, This is where the gouges used to be.