The start of the fuel tank sealing process. Everything has been scuffed (heavily) and washed with dawn detergent and followed up with naphtha before dimpling. Immediately before the parts are slathered with the black goop, it receives another wipe down with naphtha. Oh and I used a small piece of scotch bright jammed in a hex extension chucked in a drill to scuff each rivet hole on the top of the tank just for extra adherence. This was quick and easy. The stiffeners went it with ease and rivetted without an issue. I used a small piece of aluminum tubing to twirl around the rivet heads to incase them (per the mothership video). It worked really well. I also used my pinky to create a nice fillet around the stiffener instead of a popsicle stick or other. My finger worked really well because it kind of contours to the shape and I can apply enough pressure to push the sealant deep into any crevice as I'm going. Stiffeners in, I'm done for the day.