I decided to change the height of my Thien Baffle to 16”. Why? Because the HVAC hoods I have seen so far have a rapid structure change from circular to rectangle, I have a 3HP dust collector (which is unknown if a Thien Baffle can even handle a 3HP), and when you step on a 6” spiral duct you can come to 8” high and 4.5” wide oval which should be good enough. 8” x 2 = 16”.
While at the Home Depot, I bought hardboard, and 1/2” pipe insulation. I am unsure if using the pipe insulation will function correctly, but heck… for 97 cent worth a shot. I also built the support structure. This week, I’ll be getting the 1/16” lexan and ordering the 7” bellmouth (for my 7” chimney inlet to the DC).