UncleBuck
Well-Known Member
only reason i don't want to go with square is because it will reduce air flow.Duct insulation with spray tack. I get it at mechanical supply house . Spray tack is like contact cement but it will stay tacky forever. Also I would just make it square, for easy build . The supply house might have premade duct that just needs assembly with s and c lock. And of course duct seal.
PS the insulation is for condensation also.
however, i suppose i could build it square and do something like this: