I took advantage of a clear bit of weather and flew today, so I only put in a couple of hours of build time.

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When I got home my smooth rubber balls still hadn't been delivered so I decided to start sanding on my ribs. Man that is going to be an investment of time. I took most of an hour creating a rib shaped mandrel from some 2" pink foam. I figure it would offer the best support of the raw ribs for sanding and avoid any damage to the cap strips.

It's a simple 2D shape so you sand it as shown, then flip the pink foam over and put the rib back on so you can sand everything from the other side. The inside is too small to run my 5" random orbit sander and the area between the rear spar tube and the trailing edge isn't even a candidate for a detail sander (multi tool). I used a rubber "taco" purchased at the auto body place and some 220 paper and found it doesn't really reach well behind the rear spar either. I probably spent 20-30 minutes on one rib and don't consider it done.

The smooth rubber balls finally turned up about 9pm and while they're slightly larger than the ideal diameter they seem to fit pretty tight. I'll try them with some acetone tomorrow.