Plans require 2-1/2 pieces of 3/4" thick 4 x 8 sheet of MDF or equivalent for the panels.
Only moving part inside the bench besides the blower motors is the flow direction slider plate, no valves or rotating orifice disks to worry about sealing.
CFM range changes if needed are made by changing out the single orifice plate through an 8" access hole cut in the front, side or rear panel which is covered with a Deck Plate or a fabricated cover of your own design.
Edited By bruce on 1194747434