My hollow Fr3aK wing suffered minor leading edge damage in a midair collision at BASS. At the time, I just taped over the damage and continued flying. I showed the damage to a couple expert builders, and the consensus was that it should be repaired, since the damage was on the throwing peg side. Now that the contest season is over, I've commenced with the repairs.
First, I felt for soft spots and taped around the damaged area so the cuts would bisect the masking tape. The tape should help stabilize the fibers on the surface of the skin, to minimize splitting. I used a Zona razor saw to make two parallel cuts, roughly perpendicular to the spar. Since it wasn't practical to make the cut parallel to the spar with the saw, I used multiple light stroke of a snap-off razor knife, cutting straight down through the top and bottom skins.
After the damaged area was removed, I used the edges of the cut out area to mark a block of scrap foam to fit. I cut the foam to fit with the saw and knife. I used 5-minute epoxy to glue the foam block in, filling the removed skins. After waiting for the epoxy to fully cure, I carved the foam to rough shape using the knife. I removed the original tape and re-taped to protect the undamaged, adjacent surfaces, and sanded the foam flush with the wing. The epoxy at the edges didn't sand well, so I used the razor knife to carve the slight epoxy bead flush. There were very small indentations and gouges, along with a low area where I had
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