1.) you have your top collar, bottom collar, left side spacer, right side spacer, gate material.
2.) I place and glue 1 spacer in it’s place
3.) i temporarily lay in the gate and then glue in the other spacer for a nice tight fit
4.) clamp both spacers down for a number of minutes
5.) sand the rings so no strands of debris interfere with sliding action of gate
6.) put duct tape (or painters tape) on the surface that will point towards the dust collector to give that 0.005” space to ease the gate to slide back and forth
7.) align the top collar and clamp down
8.) drill holes and insert machine screws & nuts (I only did 4, tho may consider doing 6 if 4 is not enough to seal)
9.) whalla. 1 blast gate built. of course, have to cut the circle, bolt the 6” HVAC ducts in, and add stoppers but that will be tomorrow.
I’m unsure if titebond 2 glue alone is a “sealing” action between all material. I could always add silicone to the outside if air leakage becomes an issue.
And an issue arose after doing 8 of these. I should have left the tape on til the end because when I push the 6” duct into place, it bumps up against the gate with no clearance. I’ll have to elongate the holes a little to raise the 6” duct up a hair.
-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"