PU does seal that surface up better, mostly because it seals up the porosity in the gelcoat as well as being a much better UV barrier.
UH

UH...Curious as to the factory steps taken to apply a PU finish. Is everything the same (same gelcoat, same thickness, same sanding, same prep, et cetera sans waxing) then the wing is taken to a paint booth and sprayed like a car?

After spray painting, are the wings sanded or "rubbed" in any way?

What is the current "favorite" maintenance wax or polish for factory finished PU?

Thanks for your response.