Another quick session. I did a bit of sanding on the rudder bottom edge where it was a bit wavy compared to the rudder skin profile. Next, I removed the bottom, gave it a good sanding (I made some epoxy spots while working on the bulkhead), and countersunk all the attach holes. Finally, it got a coat of System 3 epoxy to hopefully plug any remaining pinholes.
Next up, primer…and hopefully not any more filler…