Here the flap is in the stand I built which holds the shape as you take the spar out to reach the inside for bucking. I also realized that I am able to shoot and buck these myself, so I am not needing to pull in Bekah's assistance on this one.
Here you see inside the bucked rivets that I was able to get to with the tungsten bucking bar. Tape evenly wrapped around it makes for a nice stable bucking set up. Also, a small piece of cardboard in the bottom of the flap (not shown) covering the rear spar adds safety.
I am leaving the end ribs till last to make sure I am able to test the straightness before setting those. In this picture you can see the nutplate and the challenge I will have at bucking that rivet underneath it.
Another problem that I am having is that the alumiprep I use to etch the aluminum before priming must not have gotten washed off all the way. As you can see in this picture, it left a etching behind on the surface skin of the underside of the flap. I think the only way I can fix this now is to finish prep in this area and then prime over it. Luckily it is on the bottom so not as obvious, but I will need to do this to both flaps now so that the final look is even until the paint job is complete.. ugh