Originally Posted by slloyd47
Bob, what material did you use for the mounting block?
Scrap 3/4" PVC board. I think it ended up a 3 1/2" x 3" cube before shaping the bottom to the roof line. Used 3M 5200 glue for building the cube and their 4000 to glue it to the roof after sanding the spot. The 5200 is permanent whereas the 4000 can be removed if you have to do so, not that it sounds like an easy task. I had both on hand and wanted to try them out.
Like the Proflex caulk, the 5200 takes days to set and comes out of the tube pretty slowly, it's thick stuff.