I cleaned the nose cone and fins with an SOS pad and dish detergent — probably redundant but why not — and sanded them with 100 grit. Now, the fins started out white and smooth and shiny; maybe I should’ve just left them like that? Well, I decided not to: I’m making sure they match the body by painting both. The nose cone definitely needs cleaning and sanding, if you’re going to paint it according to the suggested paint scheme (and I probably will). Mine also needed Bondo spot putty to fill in some serious seams.
Then I put the motor mount into the body tube, applied CA on the roots of the fins, and snapped them in.
Next you’re supposed to apply CA to the joints between the fins and the locking rings, centering rings, and tubes. After that you’re supposed to apply it around the edge of the baffle.
There’s roughly a quarter inch of space between the motor mount and the body tube; I couldn’t even see down to the forward locking ring, let alone reliably apply CA there. On the other end, I could see the baffle, but it’s way down there out of reach.
On the rear end, I basically just ended up dribbling CA in and hoping it was going somewhere useful. On the forward end, I slipped a spare BT-20 over the shock cord to keep CA off it, and then attempted to drip CA where it was needed. (I got a lot on the BT-20). Then I cemented on the rear centering ring.
The instructions didn’t say to run a bead of CA around the edges of the fin roots, but I figured it couldn’t hurt. I also applied it around the inside of the front end of the body tube.