Articles
One Great Tip » Homemade Air Filtration System
Homemade Air Filtration System
By Jerry "Jake" Seabaugh
Photos Jerry "Jake" Seabaugh
Posted: October 20, 2009
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| Photo 1. My solution to cheap clean air in the shop. |
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| Photo 2. Just a box and an exhaust fan with a big hole in the bottom. |
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| Photo 3. I used metal-clad wire because of all my shop wiring is exposed. |
Air quality is always an issue for woodworkers, especially if we are working in a basement or when we don't want to give up the heat in the shop to an open window during those cold winter months. There are plenty of 'store bought' systems out there to filter the air, but they can be pricey. So for those of us who would rather spend the money on another router or just like to make 'stuff', I have a suggestion (Photo 1).
Build a box, cut a big hole in the bottom and install an exhaust fan in it (Photo 2). Then cover the hole with a couple of disposable furnace filters and cut slots in the bottom of the box to vent the filtered air back into the room (Photo 1)
Note: follow all local building and electrical codes when making, wiring and installing the system (Photo 3).
Now would be a good time to discuss a little air flow math: My fan is rated at 1000 CFM in 1600 sq ft of attic space, (cubic feet per minute) - that is how much air the fan will move in a minute. My shop/garage is 22' x 22' x 10' = 4,840 cubic feet, 484 sq ft. So if my math is right, my fan should exchange the air in my shop in about 4 to 5 minutes. That sounds good to me.
I installed mine between the trusses in the attic, (Photos 4a and 4b) only the filters and vent deflectors protrude into the room (Photo 5). If you don't have an attic, (or your mate won't let you cut a hole up into the kitchen floor), just mount the box on the ceiling.
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| Photo 4a. The box is mounted between the trusses. | Photo 4b. I wrapped insulation around the box for good measure. |
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| Photo 5. Only the filters and vents protrude into the room. |
My garage trusses are 24" on center, so I was able to use a 15". fan. The box measures 31". x 22". x 12". high, (Photo 6a and 6b), and the base that mounts to the ceiling measures 32". x 27". I was then able to span the trusses and leave extra room for the vent slots.
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| Photo 6a. The box measures 31". x 22". x 12". | Photo 6b. Close up of fan and shroud mounted in the box. I did have to bend the shroud base up on all sides to fit. The sheet metal cuts and bends easily. |
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| Photo 7. I used two 1" furnace filters. When the bottom one gets clogged, I replace it and put the new one on top. |
I used 2 filters to get better filtration, (Photo 7). I just replace the bottom one when it gets clogged and put a new one on top.
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| Photo 8. Notice the low profile in the shop |
Notice the low profile of the finished air filter in my garage. (Photo 8) Good luck and breath deeply.
Jake is a registered member of WWGOA. See more of Jake's woodwork at his website, Saw Dust by Jake.
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20 Comments
Posted October 22, 2009 // 9:42 AM Hi Jake Great idea and good photos to go with the explanations. The note beside photo 6a has a slight typo mistake. Unless you have huge truss spacing. Have been thinking of adding more dust control to my shop and this just fits the bill. Thanks and keep breathing deep George
Posted October 22, 2009 // 11:49 AM Hey Jake, good idea! I understand you were working with 24" rafters, so that size fan might be a little large, but where did you get the fan you used? Also what is the make, model and any other info on the fan itself? Thanks, Paul
Posted November 01, 2009 // 10:25 PM I also would like to know any and all the info. you would have on the fan. thanks ted
Posted October 22, 2009 // 4:47 PM Great setup, and just the right size to do the job. Large on center numbers, but who knows except you and now all of us. Photos are just the thing, you could build it just from the pics. Thanks and be safe. JPC
Posted October 22, 2009 // 10:14 PM As far as specs on the fan. It was given to me, someone was cleaning out a barn. You can go to any big box store (I work at a Home Depot) and look at their attic fans. Just remember the CFM is important and that after the box is made it must all fit between your rafters.
Posted October 22, 2009 // 10:18 PM Okay, I'm dense. I just figured out what gmmbell was talking about. I have foot notation next to those dimensions NOT inch notation. Sorry all !
Posted October 26, 2009 // 10:11 PM Looks like a great Idea. Do you have any problem of back pressure on the fan? Looks like the vents are a little small for the air flow? How long have you been using it?
Posted October 27, 2009 // 8:00 AM No problem with back pressure, when I turn the fan on, I can see the filters lift up in the center about a full inch. I guess you can say the fan really sucks! The vents work just fine. I can stand on the floor in front of them and feel a nice breeze. I have been using the system since last February. Every time I turn it on the air just feels cleaner. I won't work without it. Jake
i would use a carbon filter last
If the fan is loud,I would use a bathroom fan and the same filters and a fiber carbon filter be put in between 2 studs in the wall and screw it.
If the y were 24'' how many inches is the gap for air flow/??
October 15,2010//10:36 pm how many monthes does your filter need replacing.? it would be good i you put a grille in front of the filters to mke it look nicr and a brand.is the filter 17''x17'' or smaller?
Oct. 15, 2010/11:51 PM how loud is the fan?
Oct. 13, 2010//3:46 PM It looks like 15'' in the fan leaves little room for air output....,how wide is the air out put? Do you use it very often.
Oct. 13, 2010/4:02 PM Thats a good way to remove sawdust. How many microns is the filters? Do you turn it on when your cutting or all the time? How many minutes does it take to clear sawdust? Do you have a timer for it?
I haven't reviewed this artical for some time. I see there are many comments. The fan isn't any louder than a box fan. I don't have any technical data. All I do know is that when I have it on I sure breath better, and when I stand facing the outlets, I feel a stiff breeze. When I turn it on the "suck" is so great that the furnace filter lifts up in the center a good half inch. I'm still very pleased with the performance.
Nice article mate, it was an interesting read. I love air purifiers and been using purifiers for a while now. I've a blog dedicated to Air Purifiers, you can check it out and let me know what you think, any feedback is appreciated: http://airpurifiersguide.blogspot.com Thanks
I would like to build this air purification system for my small shop. Can you send me the specs?
Adolph, Hi. I just happened to be reviewing my old articles and saw your post. I didn't think anyone looked at these anymore. Thanks. I don't have any specs, I just winged it. Made the box to fit between the rafters and made it tall enough to cover the fan motor. If the article isn't enough, contact me at jake@sawdustbyjake.com.
Hello :)