Whew, so I got around to it eventually. 8 RW60 corner traps, 4 for my studio and 4 for another one I do gigs for in the city. The frame is aluminium C stud that I cut with an aerial snips and then put in some self drilling screws to hold it together. Cloth is some black cotton stuff a friend helped me glue on (glue gun), just took out 2 screws on each frame and slotted the rockwool in!