I hope I can post files or this will be disappointing... I have been practicing living hinges and needed to hook up my laser to one of my garage windows to vent properly. I took out the glass, bought 1/4in acrylic, .18in birch (roughly 3/16in but marketed as 1/4in at Windsor plywood) and made this...
installed 2.jpginstalled 1.jpg6in blast gate assembly.jpgLayout, Blast Gate 6in .18in birch ply TRY2.dwg
If you have different thicknesses you should be able to adjust fairly easily. You will want reasonably good quality plywood to make the living hinge not break... Mine is pretty durable now though.
Enjoy!
Steve