Well it was cold and flat today so I finally worked on smoothing out a couple of my scratched up foils. Got some Bondo glazing and spot putty, smeared a thin layer over the scratches (mostly leading edge), and progressively wet sanded it from 320 grit down to 1200. Not perfect but a whole lot smoother (maybe 90%). The putty is dull red so you can really see where it filled in the scratches after sanding. Definitely not a very cosmetically pleasing look but I don’t really care about that. Now to try them out and see if I can tell any difference. Also to see if it lasts, since it is not as hard as epoxy and maybe will grind out first time I hit the sand.
I did this too one time. Couldn’t tell the difference. I support the effort though because the physics say it will make a difference. An aero/hydrodynamicist suggested to me that the most important part as far as surface finish is on the topside of the wing from the leading edge to about halfway back the chord. Surface imperfections aft of that or anywhere on the bottom side doesn’t really impact lift/drag. Same goes for the mast (leading edge to halfway back) and tail (leading edge to halfway back on the bottom side)