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Home Made Air Filter

12059 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.

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370 isn't much

I would not use a bunch of filters, rather just one and clean it out often or slip in a clean spare one. By restricting the air flow the motor may overheat, I donno. It probably wasn't designed to have a lot of resistance. Something about pressure levels maybe? The commercial units have a squirrel cage fan. What does your's have?
Any dust you capture is no longer in the room so whatever you can filter is a good thing. :yes:
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


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Very clean and well done. Let us know how it works. :thumbsup:
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!!!
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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......
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Ryan, in the shop built air cleaner I had I used the cheap filter first, then a Filtrete red, then a Filtrete Ultra-allergen. It was very effective, and while I had to replace the first one fairly often I don't recall ever replacing the ultra-allergen, though I did replace the red one once....that was over a 5 year or so period. I left that in the last house we had and really wish I had taken it down and brought it with me. It was ceiling hung. These type of shop built units work so well, and are so cheap I can't understand why so many of the commercial ones are sold.
I have a blower in the trunk of my car my BIL pulled for me to build an air cleaner with. I would like to get it built over the holidays.
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.
Very nice and well done, I appreciate your work.
So, you just make this and install it in some out of the way place in your shop and it takes care of everything? I have a shop that is a long rectangle, about 14 x 24 feet in size. It seems to me that if I make one of these and put it on just one end of the shop that it won't be very effective for gathering dust from the other end. I could be wrong. I read that I can use attic fans as a source of the internal fans. Would this work and be effective in my shop's particular size?
Mines somewhat centrally located, but with a big enough fan, anywhere in the shop will make a big difference.
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