I used 2 45 degree elbows instead of a long radius elbow since I couldn't find any out here in the country. For 6" blast gates I made my own, I cut 2 squares from 3/4" plywood, cut a hole for the pipe and cut 1/8" birch plywood for the spacers and the sliding part of the blast. Attached the spacers to the plywood with glue leaving enough room for the gate to slide. Attached to the pipe with RTV.