James F. Aguiar wrote:

I have two plastic Peception Arcadia kayaks that are somewhat
scratched. I have tried to wet sand, compound, but nothing seems to
work. All I seem to get is a white chalked finish. Are these plastic
kayaks unrepairable? Jim

Don't waste your time. There's little you can do to resurface a plastic
boat. They scratch so easily that any effort you put into smoothing the
surface is largely a waste of time. Sanding and compounding doesn't work
because the material is too soft. I suggest that you just paddle them
and forget about it.

If you're determined to do something with the surface, larger "hairies"
can be removed with a razor blade and smaller ones can be flattened with
a heat gun or by passing a propane torch over them (use a flame
spreader). If you go this route, be careful, as the hull material melts
at a low temperature. Deep gouges can be fixed by plastic welding.
Harbor Freight sells a plastic welding kit for $20 or so that should do
the job, if you feel you need it.