Box Fan Dust Filter (For fine airborne dust)

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Project by Trev_Batstone posted 01-25-2012 10:28 PM 7289 views 15 times favorited 26 comments Add to Favorites Watch

I realize that this type of dust filter does not eliminate a commercial dust filter system for collecting sawdust at the source of power tools (which I hope to acquire soon), but never the less I wanted to make a box fan dust filter to collect fine airborne dust in my small shop. I bought this box fan on Craigslist a couple of days ago, and purchased a 20”x20” furnace filter at Home Depot and finished the project this morning. I installed the eye bolts to the metal box on the complete opposite side of where the speed control knob is, so that the unit would actually hang upside down. This enables me to easily reach up to turn the fan on or off. The bottom of the box fan when hanging is high enough to clear my head when walking about, but low enough to reach the control switch. The eye screws in the ceiling are screwed into ceiling joists so that there is no danger of it to come crashing down. Total cost of this project was about $22. Time will tell if it works, but even if it is not effective in collecting fine dust, I will have a cooling fan for the shop during the hot summer days. Thanks for looking.


26 comments so far

View ChrisK's profile


1996 posts in 3223 days

#1 posted 01-25-2012 10:44 PM

I do the same thing, except that I left mine more portable so I can move it to where I am sanding. It helps.

-- Chris K

View DamnYankee's profile


3312 posts in 2704 days

#2 posted 01-25-2012 10:45 PM

Cool idea. How well has it worked for you?

-- Shameless - Winner of two Stumpy Nubs Awards

View HalDougherty's profile


1820 posts in 3379 days

#3 posted 01-25-2012 10:46 PM

Good looking filter. Getting the dust out of the air you are breathing is one of your most important projects. Only one problem. I built one about a year ago and used it one time. Every filter I tried was plugged in an hour or less and the filters are expensive. I only used it till the pack of furnace filters I bought was used up, then reused the plywood box as a stand for a tool. My solution to the dust problem in my router room was to put in a window fan and open the outside door a little. It keeps the dust down and filter cost isn’t a problem. Oh, if I’m working on any woodworking project I always wear a respirator. A good one!

-- Hal, Tennessee

View Michael Wilson's profile

Michael Wilson

588 posts in 2632 days

#4 posted 01-25-2012 10:55 PM

nice! I’ve got one on my floor with the filter bungeed to the back of it. I’m amazed how much it pulls out of the air where it is. Keeping it high like this would definitely be an improvement (fewer obstructions up there.)

View ajosephg's profile


1880 posts in 3703 days

#5 posted 01-25-2012 11:18 PM

I am no dust expert by any stretch, but somewhere in the dusty (pun intended) archives of my brain, I seem to remember that it is the really fine dust, less than 5 microns, that is a health hazard. I think the theory is you cough up the big stuff, but the small stuff stays in there and can lead to lung cancer, etc.

A furnace filter arrangement as shown will in no way catch 5 micron dust. So – while it may reduce the visible dust in your shop, you will still be inhaling the dangerous stuff.

-- Joe

View Jim's profile


150 posts in 2511 days

#6 posted 01-25-2012 11:39 PM

I thought I’d share this with you and you can get finer filters that will filter the finer dust particles. We have them at work

-- Measure twice, cut once.

View Jeremy Greiner's profile

Jeremy Greiner

568 posts in 2913 days

#7 posted 01-26-2012 12:51 AM

I’ve always wondered if these box fans with a filter attached worked at all, do they really push around enough air to notice a difference in the airborne dust collection?

-- Easy to use end grain cutting board designer:

View Michael Wilson's profile

Michael Wilson

588 posts in 2632 days

#8 posted 01-26-2012 01:10 AM

In a 20×20x8 workshop I can see the difference in an awfully short time checking for “dust in the light beam” of my shop lights. I have to vacuum out the filters every five or six hours of shop time as the fan will start to whine about the pressure.

View Tokolosi's profile


678 posts in 2497 days

#9 posted 01-26-2012 01:12 AM

Great Idea. My dust collection consists of moving table saw/miter saw and router table to the driveway. I have a shopvac for my sanding station and a constantly bl;owing in the direction of the open garage door. Still dust gest on everything. Going to try one or two of these inside my garage work area.

-- “There is nothing like looking, if you want to find something. You certainly usually find something, if you look, but it is not always quite the something you were after.” ~ JRR Tolkien

View blackspring's profile


36 posts in 2502 days

#10 posted 01-26-2012 02:14 AM

Nice idea Trev – I’ve seen variations of this setup. Just getting my shop setup myself, I’ve been trying to solidify a plan for effective dust collection. Anywhere in particular you mounted this – relative to your tools I mean? Could this be mounted flat with, say, 12” between the fan and your ceiling?

Joe’s comment above makes sense and concerns me a bit. If anything over 5 microns (the visible stuff) is eliminated with this filter, that’s great for the stuff you can see. It’s the stuff you can’t see that is harmful.

I’d be curious to hear some comments from anyone who has an effective dust collection system. Do the units like the Delta and General (i.e. 1HP blower motor and 1micron filter bag) do an adequate job of eliminating the smaller particulate? This may be fuel for a topic already covered to death on the forums, but I’d be interested to hear peoples general thoughts/concerns on this.

View dbhost's profile


5767 posts in 3373 days

#11 posted 01-26-2012 02:25 AM

Similar to what I did at first, except a nicer implementation. I used duct tape…

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View crank49's profile


4032 posts in 3112 days

#12 posted 01-26-2012 02:40 AM

I have one that was actually made at the factory with a frame and clips to hold the filter. It is otherwise exactly the same as other box fans.

I buy the best filter for it I can find locally (which sells for more than I paid for the fan by the way) and it does a nice job. The filter I use looks like pleated coffee filter paper rather than fiber anything. Supposed to capture 98% to 99% of dust down to .3 microns.

Would probably have to have three of these modified box fans (at $32 each with filter) to equal the air flow of a true ceiling mounted filter, but every little bit helps. They do make much more noise than a real filter.

View Blackie_'s profile


4883 posts in 2654 days

#13 posted 01-26-2012 02:43 AM

Even with a complete DC system 4” piped through your shop as I have in my shop you are still going to have dust particle’s flying around so anything you can do to reduce is good as Hal suggested I’d still recommend some sort of dust mask, I use the Dustbegone along with my DC.


-- Randy - If I'm not on LJ's then I'm making Saw Dust. Please feel free to visit my store location at

View a1Jim's profile


117232 posts in 3719 days

#14 posted 01-26-2012 04:40 AM

Interesting dust collector.

-- wood crafting & woodworking classes

View Trev_Batstone's profile


317 posts in 2634 days

#15 posted 01-26-2012 05:01 AM

Thanks everyone for your comments. I’ll now try to answer some of your questions. How well does it work? I only completed and hung it up this morning, and haven’t done anything in the shop for the rest of the day. I must admit that the filter that I have installed on the fan is just your basic ($6.99) filter. I bought this cheap filter purposely just to see how effective the fan will draw in the dust. If after a few days of using power tools I find that it does suck up dust, then I will most certainly buy a high quality filter for it that is rated for capturing the really fine dust. I am 6 ft. tall, and this unit clears my head by about 4 inches, so no danger of me hitting my head on it. I’m thinking of attaching a chain from the bottom center of the fan and tilting it back to about 45 degrees, in hopes that it may pick up dust from a lower area of my shop.. I would need about a 3 ft. chain and another hook in the ceiling to do this, no big deal. I could still easily reach the control knob, no problem. I have this filter connected to my ceiling light in the shop, so when I enter the shop I just flip on the light switch and the fan comes on automatically, and shuts off when I turn off my light switch when I exit the shop. Of course, I can still turn the fan on or off at whim with the switch on the fan unit itself and also control the speed. And yes, I also wear a dust respirator when using the power tools. I’m also going to be buying a wet/dry shop vac later this week (hopefully a Rigid model) and hose connectors for my power tools to pick up the larger sawdust particles and wood chips.


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