I used a couple of long bolts to protect the threads in the end caps when I primed them with NAPA 7220. My folding ladder wasn't tall enough for the F-790 by itself, so I clamped a board onto it so I could hang the tube for priming. Sprayed primer in each end but the tube is so long very little made it out the other end, the primer dries along the way. Sprayed the outside of tube and let it dry.
