Tonight's session started with some final deburring and scuffing of the right wing's rear spar with a Scotch-Brite pad to roughen up the surfaces for priming. Then after a quick wipedown with acetone, I started spraying the self-etching primer. In all, the parts I primed were the rear spar, the spar attach double, spar attach fork, and the three doublers for the aileron and flap hinge brackets.
What's next? Time to start riveting the rear spar to these pieces.