I started the session by doing some final dimpling and machine countersinking of the spar doublers of the vertical stabilizer. This required some careful reading and research since I wanted to be sure that I was doing these operations on the correct side. The VS skin and the flanges of the ribs also required dimpling of its surface for flush rivets, which I used either the hand squeezer, the DRDT2 table dimpler, or the close-quarters pop rivet dimpler as appropriate.
Next was to finish scuffing all of the surfaces with Scotch-Brite pads, wipe down the parts with acetone, and then spray a coat of self-etching primer on them.
What's next? Cleco all of these parts back together and start riveting them.