Final Prep (Dimple, Countersink, and Shape)
07/24/2021 – 0.5 hours
I prepared the aft fuselage access cover plates a little earlier than the plans indicated so that I could use the final, dimpled cover plates to test the fit with the nutplates installed in step 10-20. Each cover plate has eight holes, straight edges, and smooth curves; so deburring went quickly with no surprises. After priming the interior face of the cover plates, I dimpled the holes with the #6 screw dimple die.
[Hole and Edge Deburring Tools, Bench Grinder with 6” Scotch Brite Wheel, 22” C-Frame with #6 Screw Dimple Dies]
Prime
07/24/2021 – 0.5 hours
Priming the aft fuselage access cover plates was straight-forward since they are small, flat parts and I only primed the inside face. I scrubbed / scuffed the inside face with a Scotch Brite pad and abrasive cleanser, rinsed and dried the parts, final cleaning with degreaser and latex gloves, and then applied the primer.
[Grey Scotchbrite Pads, Bon-Ami Cleanser, Dupli-Color Degreaser, Dupli-Color Self-Etching Automotive Primer (Green – Rattle Can)]
Assemble
10/01/2021 – 5.5 hours
10/03/2021 – 0.7 hours
The top skin on the aft fuselage is flat, so it looked like a good candidate for back-riveting. That turned out to be a great approach starting at the forward end of the fuselage and working aft through about half of the rivets. I set up the back-rivet plate on the garage floor next to a carpeted flat surface at the same height, and put the fuselage upside down on the rivet plate. The results were really good, and I definitely recommend that approach.
The back half of the fuselage was too hard to reach for back-riveting, so I called a fellow builder to help me buck the aft portion of the top skin. We set the fuselage on its side since the sides are also relatively flat, and there is less structure on the sides to damage as the inside person lies across the bulkheads and longeron. I used several beach towels to build up a surface to lie on that was the same height as the bulkheads, and then used a lounger cushion on top of that. The 2-man approach on the final rivets went quickly and ended up very good results. At the end of the day all the rivets were set successfully with none that had to be drilled out and replaced.
The final three rivets for this part of the build connects the rib on the top skin to the first full bulkhead. Those rivets are deceptively hard to get to, and I had to use the double-offset cupped set and bucking bar to set the rivets. I was excited to finish those rivets and this section of the build. On to the wings!
[3x Rivet Gun, Large Back-Rivet Plate, Back-Rivet Set, Flat Rivet Set, Double-Offset Cupped Set, Tungsten Bucking Bars]