Chapter 6 Empennage Date 1/15/00 Procedure HS-1 The first thing to build is the horizontal spar. Shaping the flange strips and locating the holes for the rivets is the first task. Locating the flange on the spar channels is the next task. I chose a PPG product for the primer DP401 is a self etching epoxy primer. After all the parts have been primed it is time to assemble. I used a rivet gun to set the rivets. (Image) workbench