Woodworking Talk banner

Home Made Air Filter

12060 Views 12 Replies 6 Participants Last post by  ryan50hrl
Ok, so I finally got around to building my air cleaner today......I had intended to build it into the rafters to save space, but with the low ceiling (7 foot basement) and the lack of a clean run of rafters (wiring, plumbing, hvac, lighting, ect. has made me build a free standing one. So i've built it to use 20x20 furnace filters. It uses a 370 cfm fan from a kitchen chimney hood. which I intend to duct over into the next room to dump the clean air. The thought behind this plan is to increase the air pressure in the other room, decrease it in my shop, thereby creating an ever so minor breeze back into the shop.

Anyhow.....my current stage is deciding on the number and type of filters. I'm trying to decide between 2 and 3 filters. Heres what I plan on using for sure.....

Stage 1

Stage 2

Should I use this one for a 3rd and final stage?


My concern is that a 3rd stage will reduce air flow......however the air would be cleaner.

1 - 7 of 13 Posts
Its a pretty heavy duty cage type fan, I'm not terribly concerned with it overheating from a few filters. The commercially available units like the delta, jet, ect units use multiple filters, and my thoughts behind multiple filters is that the low cost first stage filters are going to catch the majority of the dust, and need to be replaced more often, however i'd like to also have higher quality filtration that removes more from the air, and thats going to take more expensive filters.
Well all built, total cost 17 bucks


See less See more
Well I had intended to use a 20x20x4 inch filter for the secondary filter, however no one stocks a 20x20x4.....and one main point I wanted to hit was cheap, easy to get, fast to replace filters. So instead its using a cheap dollar filter for the first stage, a 3 dollar 2 inch filter for the second stage, and then a 20 dollar (that I got for 12 bucks) premium filter for the final stage...

The fan is a 370 cfm cage fan out of a fairly high end chimney hood that I got for free (hood section was damaged beyond use, but the fan was untouched and never ran. The fan at full speed is almost silent.

Plywood is all leftovers from renovations....it made its first 40 years in life as a closet shelf......scrap strips for mounting filters is all scrap from building doors.

Total investment....17 bucks plus tax!!!
See less See more
I flipped my sander bag over on the table saw and used the compressor to blow it all airborne......flipped on the cleaner and within about a minute the air was very clean....within about 3 minutes.....I couldn't tell the difference between shop air, and outside air.

This first run was one of projects that I didn't have a plan for when I started, I just kinda threw it together as I went, consequently its really a bit deeper than it needs to be........but then again that may aid air flow within the box......
  • Like
Reactions: 1
It seems to work really well so far, my shop is segregated from the rest of the basement so my plans Is to dump the clean air onto the other side of the basement, creating a small draft back into the shop further containing the dust.
Mines somewhat centrally located, but with a big enough fan, anywhere in the shop will make a big difference.
1 - 7 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.