In this session, I started by mixing up another small batch of tank sealant and applying it to the flanges of the remaining half of the inboard rib for the left tank. Sliding it into place went pretty smoothly, and so I started bucking the rivets to the skin with the air rivet gun.
Tackling the larger rivets that join the two halves of the rib together to the attach bracket was a little more challenging. I had to use a 6-inch long drill bit to open up the holes slightly more so that the rivets would slide in, and then I had to use the double-offset rivet set in order to have the clearance to buck them. After that, I went about encapsulating all of the rivet heads with more tank sealant and fileting all of the seams where the tank sealant squeezed out. I also applied a bit more along the inner corners where the rib meets the attach bracket. Next, I used the hand squeezer to add on the remaining 5 nutplates along the inboard edge of the tank skin.
What's next? With this done, the major assembly of the left tank structure is basically complete, with the exception of the last baffle that will close in the tank. Once I feel the sealant has cured long enough, I might try filling the tank with water and see if there are any obvious leaks. I still also have to bend the float arms for the fuel sender.