Nice job . . . but as a side bar - if you have a "climate controled shop" you would be sucking all your heat or air-conditioning into the lean to . . . you might want to seal it up the best you can and vent the air back into the shop . . . otherwise you will be changing the humidity and temperature every 5 minutes . . .
Good observation, and if I vent it outside what do I need filters for?
Laugh, I don't know, that was my first DC system and I thought all dust collection systems needed filters. I guess I was thinking my neighbor might not like breathing the fine dust, his house was only 15ft. away. But good point.
The one I have now in the soundproof enclosure has a return air grill back to the shop. I was worried that it would also return the noise too, but it doesn't seem to be that loud. The sound proofing must be absorbing a lot of it.