On Wednesday, September 9, 2020 at 2:29:22 PM UTC-4, Chip Bearden wrote:
What UH said. He allowed me to supply a huge number of hours of work when we refinished my ASW 24 a few years ago. With two guys in the workshop (sometimes three), it was actually enjoyable sanding and talking soaring. But it takes a long time. I'm sure there's an easier way but I haven't talked to anyone over the years who's found it.

I recall there were spots--areas, actually--especially on the fuselage, where the gel coat just seemed a lot harder to sand than in other spots. And it was unrelated to whether it was over a seam where you would expect to encounter a slightly different gel coat/hardener ratio. Maybe it was where the factory had patched defects in the gel coat coming out of the molds?

One other thing--and I'll defer to UH and JJ on this--is that I wouldn't have started with the stab and elevators. The elevators and ailerons were the touchiest surfaces for me to sand, both removing old gel coat and finish sanding PU. The narrow chord combined with slightly concave surfaces meant it was really easy to sand through. And, of course, due to weight/mass balance considerations, we couldn't just spray on a whole bunch of stuff and sand some of it off. The sharper leading edge of the stab and the tight compound curves around the fairing for the rudder are a little fussy, also.

I had done some contouring/profiling on wings in previous years but was otherwise a rookie. If I were approaching it again, I would do it the way UH did. The first winter we did the fuselage (sans horizontal tail). The surfaces were big and relatively easy to sand and the consequences of slight imperfections were smaller. The compound curves, especially on the forward fuselage, were less of a problem than I had thought. In all, it was a good project on which to learn some technique.

The next winter we did the wings and tail. We were very careful with the wings because I think I have a "good" '24 and didn't want to have that little edge disappear in the dust. So we pulled leading edge templates from one wing and used those when applying the filler/primer. UH also wielded the grinder when we did the "B" leading edge mod and then we used templates to profile the outer portion of the wings where that applied (the leading edge is less sharp on the ASW 24B on the outer wings).

Sanding the big surfaces--fuselage and wings--went faster than I thought. My biggest mistake was not wanting to swap in new sandpaper often enough. It was still cutting but just not as fast. UH will laugh or be moved to tears for all the times he encouraged me to change paper and I declined.

It was a therapeutic, educational, and rewarding experience. And the glider still goes great and looks like new. We even did a few upgrades: e.g., UH's fuselage vent and filling in the factory water dump ports on the wings.

Chip Bearden
JB
Chip, the therapeutic part of this comes from me not listening to the wife complaining about not being able to fly her glider. The educational part derives from my approach to spending more time doing things than required, but they are done correctly. The rewarding part of this ordeal is that I know P1 would be happy to see the old girl looking great again.