First, yes that is blue painters tape covering the leading edge skin of the vert stab. A lot of people recommended removing the all of the protective film sooner than later. So I did. And ended up with a significant scratch in the horizontal skin so I applied the tape here to help prevent scratches. I have since acquired a soldering iron and am now following what the rest of the crowd recommends…
In these pictures you can see that I used CherryMax rivets to attach the two inner ribs to the forward spar. Setting these rivets takes a little getting used to and I had to drill out a couple in this phase of the build. YouTube videos to the rescue again! For reference, I am using a manual CherryMax rivet gun that I have covered in Gorilla Tape (helps prevent inadvertent scratches on the primer)
Doug's F1 Rocket Build 