After modifying my Harbor Freight dust collector, I needed a filter for the discharge of the blower. The dust collector mod did a great job eliminating a majority of the dust, but it was still discharging fine dust into my workspace – something I didn’t want to be breathing. This time I drew up a plan in Sketchup and used it to guide me in this build. The build was rather straightforward, and a made small changes here and there where it made sense.
I call it a 3-stage filter because the first chamber acts as a baffle to slow the velocity of the air down, then it passes through a 5-micron prefilter and finally through an allergen reducing furnace filter. The box is so efficient, that I haven’t seen any dust on the furnace filter yet, so I am pretty satisfied with the outcome. I hope you enjoy the video.