Fixing my Nutplate Faux Pas

Well it took me a while but I finally got around to "fixing" my nut plate mess that I made per my previous post. My spar looks like crap with all the primer spots all over the place, but it is what it is.....

I drilled out two of the three nut plates and replaced them. Turns out I had to replace one of them twice because I still could not set the rivet properly. What a pain. The process was as follows:

I used the Gorilla tape to cover the vulnerable areas. I should have used it from the beginning,but oh well... I covers the areas with strips of tape, and then I also decided to switch bucking bars. I reasoned that the thin man bar has a longer moment when you use the end of that one as opposed to the fat man bar, which concentrates all of its weight closer to the surface being riveted. IOW it is easier to handle in tight spaces when using the small end of the bar compared to the smaller but longer thin man bar. I did not use it initially because I was afraid that the bar was too big for the area surrounding these nut plates. Turns out I could adequately get it into position for all but one of the rivets.

The other thing that I did differently was to be very sparing with the gun. NO quick squirts of the trigger this time. Instead I used very short taps to set the rivets in place, and then more short taps to slowly set the rivets the rest of the way. I also paid much closer attention to the placement and control of the bucking bar, being very careful not to let it slip or cant over to one side.  I did have to use the corner of one of the bars for one of the rivets. I spent a long time working the positioning of the bar in my hand with my fingers in key positions to prevent the bar from sliding off and hitting the backer plate of the spar.

I set the rivets and new nut plates first, then I proceed to sand out the small gouges and scratches to the backer plate of the spar web, followed by some more 7220 primer applied with a Q tip. I am now satisfied with these three nut plates.

Here you can see the tape still in position with the new nut plates riveted on. I also wanted to share a little tip about close quarter clamping techniques. Note the empty cardboard tape roll that I slid down over the jack screw of the C clamp holding the wood block in position against the spar. I realized that this was just another  accident waiting to happen. The threads from the clamp were so close to the spar web that I knew that the tapping from the rivet gun might cause more damage if I did not somehow find a way to protect the spar. So in a brief moment of creativity I came up with the idea to use the empty tape roll as a barrier between the clamp threads and the spar web. You just never know what you might end up using to build an airplane!

Next I start riveting ribs to the spar.