In this session I continued prepping a new rear spar doubler by cutting out the oblong hole for the aileron pushrod, using a series of drill holes and a rounded metal file. Then I primed it, and riveted in the spots that only attach it to the rear spar. I also primed the wing walk doubler plates. The primer is a different color because I'm trying out NAPA 7220, which is apparently the same as Sherwin Williams GBP 988 self-etching primer, and was highly recommended by a few builders on VAF forums. It definitely seems to spray on thinner and have a smoother less-chalky finish, and dries extremely rapidly.