There was a tip a few years back in FWW where someone took a box fan, and attached a furnace filter to it with some wood blocks to hold it in place. The beauty of the design, once built, was that it was super easy to switch out a dirty filter….
I remembered this old tip, and snagged a 20” x 20” box fan last weekend when i went out to pick up a new dehumidifier. The old one nearly started a fire when I plugged it in. Flames were literally arcing between the plug and the extension cord, one of the prongs half burned off!
Heading over to find the filters – many options to choose from as far as filtration goes – and all conveniently 20 inches square!

I figured I’d just use duct tape to secure the filter to the back side of the fan – so it could pull the air away from where I was working, the force of the fan pulled the filter in place – magic has kept it there, no affixing necessary (the floor must slope away ever so slightly, and gravity is really doing the job.
Does it work:

You bet!
Is this a replacement for proper air filtration and safety gear? No. But I have noticed a huge difference in my comfort level. (Temperature, visability, breatheability) I could also finish my Thorsen Table – sanding wood and stone alike – without tripping the smoke detector!
-- I am always doing what I cannot do yet, in order to learn how to do it. - Pablo Picasso -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/






















21 comments so far
mot
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4903 posts in 934 days
posted 909 days ago
Very nice! I suppose that is really all the fancy overhead units are doing anyway. Thanks!
-- You can discover more about a person in an hour of play than in a year of conversation. (Plato)
WayneC
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6044 posts in 995 days
posted 909 days ago
Great idea Scott. I was actually looking at some of the old posts on this topic on the site tonight. This sure is a simple approach.
-- We must guard our enthusiasm as we would our life - James Krenov
scottb
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3402 posts in 1225 days
posted 909 days ago
Simple, and fairly cheap…
not as cheap as the time I used half a wine cork to repair the fan in our freezer. The tech who came out to replace the motor – still under warranty – broke the fan shaft and it was LOUD. We would have had to suffer with it while we waited for a re-ordered part… Ironically, my fix was quieter than the replacement part, and worked just as well.
-- I am always doing what I cannot do yet, in order to learn how to do it. - Pablo Picasso -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/
Bob Babcock
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1808 posts in 984 days
posted 908 days ago
I like that one Scott…i’m going to do it as well until I can get something better…which probably means I’ll have it for a couple years….:)
-- Bob, Carver Massachusetts, Sawdust Maker http://www.capecodbaychallenge.org
Dick, & Barb Cain
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7043 posts in 1197 days
posted 908 days ago
Good going Scott.
It looks like it does the trick for you.
-- -** You are never to old to set another goal or to dream a new dream ****************** Dick, & Barb Cain, Hibbing, MN. http://www.woodcarvingillustrated.com/gallery/member.php?uid=3627&protype=1
Roger Strautman
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534 posts in 1031 days
posted 908 days ago
At least you were there when the flames started and you caught it before a big fire started.
-- " All Things At First Appear Difficult"
Karson
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25806 posts in 1298 days
posted 908 days ago
Greay idea Scott. Thanks to MacGuyver also.
-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †
Bill
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2561 posts in 1059 days
posted 908 days ago
Great idea Scott. It looks like you did not buy the cheapest filter, which is probably a good idea. This will pick up much more dust. Since you did not trip the smoke alarm, you can tell it is working.
Better keep a supply of filters on hand.
-- Bill, Turlock California, http://www.brookswoodworks.com
Karson
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25806 posts in 1298 days
posted 908 days ago
Scott, did you use any of the filter coating sprays that assist in trapping dust?
-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †
Greg3G
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770 posts in 983 days
posted 908 days ago
I was thinking of doing the same thing myself. I was going to hang 2-4 of them around the shop. I really need to keep the air moving in there or it gets way to hot in the summer. Might as well clean the air while I’m at it.
-- Greg - Charles Town, WV
Mark1
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6 posts in 918 days
posted 908 days ago
love it, i have been over thinking the same idea for a while and this is so simple thanks!!!
-- Great things begin in chaos
scottb
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3402 posts in 1225 days
posted 908 days ago
Yep, this isn’t the cheapest filter – there was a 3 fer pack at the same price point. There was also one or two that cost more (2-3 times the cost of the fan!).
Filter coating sprays? I know not of such a thing. Would those be found nearby?
The fire started just as I was putting the plugs together. Had it not startled me I wouldn’t have dropped it on the dusty floor and could have pulled it out immed. Although it seemed to take a long time, It probably only took me a second to bend down and get them apart.
-- I am always doing what I cannot do yet, in order to learn how to do it. - Pablo Picasso -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/
Bill
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2561 posts in 1059 days
posted 907 days ago
I was in Lowe’s this weekend checking on some other items, and saw they had a few box fans in. The 20” fan was only $13.87. Add in a few bucks for a filter, and for $20 you can have yourself an air cleaner for your shop. I may stop by and pick one up, along with a filter.
-- Bill, Turlock California, http://www.brookswoodworks.com
RobS
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1243 posts in 1204 days
posted 907 days ago
Wow all these comments, you sure must have a lot of fans!!!! Great idea thanks for the tip.
-- Rob (A) Waxahachie,TX
Karson
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25806 posts in 1298 days
posted 907 days ago
If I remember correctly the spray was with the filters.
-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †
Paul
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607 posts in 990 days
posted 904 days ago
I’ve seen this simple air cleaner written up several times.
I picked a box fan up off the curb on trash day some time ago for this very purpose (it works!). But I haven’t gotten around to picking up a filter and building the frame to hold it.
Thanks for the prompt!
-- Paul, Texas
Jack Erickson
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9 posts in 1022 days
posted 904 days ago
This setup was reviewed in one of the woodorking magazines. It was shown to do a very good job of removing dust from the shop…
-- Jack
oscorner
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4572 posts in 1209 days
posted 904 days ago
I’ve been using this method for years. I find the filter cuts the airflow from the fan by about half, so it’s cooling effects are reduced. It does a great job when put next to a project during sanding, drawing all that fine dust into the filter and not letting get all over my shop.
-- Jesus is Lord!
WayneC
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6044 posts in 995 days
posted 779 days ago
Any more projects in the works for this series?
-- We must guard our enthusiasm as we would our life - James Krenov
scottb
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3402 posts in 1225 days
posted 779 days ago
any more… surely so… Did I tell you about the time I “MacGuyvered” the fan in the freezer? – the one the repairman broke?
-- I am always doing what I cannot do yet, in order to learn how to do it. - Pablo Picasso -- http://blanchardcreative.etsy.com -- http://snbcreative.wordpress.com/
Dadoo
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1723 posts in 888 days
posted 779 days ago
So simple. What a great idea. Already got me thinking of how I’m gonna modify mine and also circulate the air to cool the shop.
-- Bob Vila would be so proud of you!