Since tonight's session had the goal of riveting in the J-channel, I decided to try out one of the tubes of tank sealant I have rather than mixing up a batch from the can and spreading it. This was the first time I had used the tube applicator form of this tank sealant, so I had to carefully read the instructions about how to mix it in the tube but this was a pretty easy process. It was definitely nice to be able to squirt a long line of this tank sealant directly onto the J-channel, though I still used a popsicle stick to smooth and distribute the sealant across the entire surface.
Sliding in the J-channel into place while it had the tank sealant applied did tend to leave an excessive amount on the inboard side of the tank (the side it was being inserted from), even though I was trying to avoid letting it drag during the insertion. Riveting the J-channel went pretty smoothly, with only a couple of rivets needing to be drilled out and re-set in order to ensure flush fitment. After that was encapsulation of the shop heads with more sealant and smoothing the top edge of the J-channel. I wasn't able to apply sealant or inspect the underside of the J-channel, so I'll probably have to find a mirror or something later.
Since I still had some tank sealant remaining, I decided to install the attach bracket as well. This went pretty smoothly, though there was one rivet I had to redo as well. The rivets along the mating seem of the first rib's halves were left only held in place with clecos, since the instructions say I need to do some tube flaring+bending before installing the other half of the first rib.
With a little bit of tank sealant remaining from the tube, I went over all of the previously installed ribs and added more along any of the seams that needed more