November 15, 2019

Right Wing Skins and Starting Fuselage Assembly

I consulted TAF about my damaged rear wing spar, and they advised against repairing it so they will send me a new one. That limits how much I can do on right wing assembly for now, but we had some nice weather this weekend so I decided to prime the right wing skins along the rivet lines so that they’re ready to attach. I already have most other components for the right wing primed and ready for assembly.

I occasionally like to make sure the primer is adhering well, so I perform tape pull tests after the primer has been given a day to dry. I wasn’t too happy with primer pulling up on a recent part I was working on, so I made a slight process change – instead of using Scotch Brite to scuff the surface, I’m now using 400 grit sandpaper. I think the plastic protective sheeting that’s applied to the aluminum leaves behind an adhesive residue that the Scotch Brite doesn’t quite release. Wet-sanding with the 400-grit paper and water seems to work pretty well, so that’s what I’m doing going forward.

Sanding and cleaning the skin. I’ve had some mixed results using Scotch Brite pads, so now I use 400 grit sandpaper only and have had much better results with primer adhesion.
Same skin after cleaning off the sanding residue. First I wipe off the wet sanding residue with a clean cloth, then wipe with a clean cloth with a small amount of acetone, finally wipe with a clean cloth with a small amount of isopropyl alcohol.
All primed and ready – I usually get the desired finish with 3 coats of the primer

I decided to start assembling fuselage components, starting with the ribs of the rear fuselage. Assembly of these components was straight-forward.

Rib 8
Completed rib 8 and rib 9; they come together later on in the assembly.

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