After completing the tanks, a section without proseal was a welcome relief. The main spar section basically has you use the main spar as a drill guide for the stiffeners that will be used in later sections. Aside from that, just a WHOLE lot of of countersinking and nut plates.
I put a piece of tape over the crack on the forward side of the spar to minimize the shavings that would get stuck as a result of all the counter sinking.
Next, I shot some primer on the top and bottom flanges and installed the autopilot servo mounting bracket.