Shop Built Air Filtration Unit

[Steve Mellott]

I have a Dayton furnace blower and would like to build an air filtration unit. (I already have a dust collector). Has anyone built an air filtration unit? If so, what did you use for filters? Can you use high grade furnace filters? Any pitfalls I need to be aware of if I build one? Thanks very much.

[Tim Morton]

I think if you search here and google you will find alot of plans for DIY filtration units. I bought mine, and I can assure you that building one would be pretty easy :)

[Paul Williams]

I built two for my shap. I used furnace filters. Just a box enclosing the fan and a recess to hold the filters. I have the filters two deep. The first is "standard" the second is a 95% high effeciency filter. You do not have the capacity of the bag filters, and have to change more often but it was cheap and they work.

[Bob Herpolsheimer]

Hi Steve,

I have a home made. I was friends with some electricians at a heating/air company so I got one of their throwaways. It's pretty easy. I started with the filter and picked out what I wanted to use for a filter and made my dimensions from that. I just made a box from 1/2 inch partical board. The filter is just a pressure fit. Electrical, the motor is a two speed so I got a SPDT switch rated for the correct amperage the I wired to in a box mounted to the side. I works great! About 3 times the CFM of a unit you can buy. On those bad days when I burn a piece of stock, it clears out the odor in about a minute. I pull the filter and blow it clean with compressed air about once a month and change it twice a year. Hope that gives you some ideas.

[David G Baker]

A few years back I ran a motion picture film processing lab. The processor had a fan similar to a forced air furnace fan that was used to dry the film. The air intake was covered by 5 fiberglass furnace type filters. The film never had a problem with dust or dirt on it. I would change the outside filter every two weeks and put a new filter in the first position closest to the fan.
My answer is yes, a furnace fan and filter set up is a very good idea for filtering out the fine dust that comes from woodworking. If it is good enough to work for film it will be good enough to protect you. You can do some Internet research on how fine a filter you want to use for your setup.

[Stephen Pereira]

here is one option..http://users.goldengate.net/~kbrady/DustCollection.html#9

[Steve Mellott]

Thanks for all the good responses. The website recommended by Stephen is very informative.

[Greg Narozniak]

Another Home built one here. Mine is 1/2" ply and I have 3 16x20 furnace filters on the intake with a 1/4hp 4 speed fan. The first is a throw away cheapy, the second is a 3m Blue label one and the third is a 3m Purple label. I will change the cheapy when it is coated and in the 3+ years the Blue Label filter never has anything on it. The Purple is overkill but when I built it I did not know. I only use the highest speed as I have not figured out a way to make the speeds work.

I have an Electrostatic filter that I was going to try on the intake but I never got around. I have been meaning to take pics of it. Maybe tonight.

[Todd Hyman]

I built mine from a furnace fan as well. It is 3 sppeds and I wired a 12 hour timer switch in series with a bathroom switch (Broan from Lowes). The filters are from HD and are 20 x 20 as I already had an electronic one and did not want to not use it. I also have a pleated filter on the exhaust side. It works great! Here are some other threads that may help you.

http://www.sawmillcreek.org/showthread.php?t=49073

http://www.sawmillcreek.org/showthread.php?t=49133

http://www.sawmillcreek.org/showthread.php?t=41172

http://www.bt3central.com/showthread.php?t=7408

[Randal Stevenson]

I built mine from a furnace fan as well. It is 3 sppeds and I wired a 12 hour timer switch in series with a bathroom switch (Broan from Lowes). The filters are from HD and are 20 x 20 as I already had an electronic one and did not want to not use it. I also have a pleated filter on the exhaust side. It works great! Here are some other threads that may help you.

http://www.sawmillcreek.org/showthread.php?t=49073

http://www.sawmillcreek.org/showthread.php?t=49133

http://www.sawmillcreek.org/showthread.php?t=41172

http://www.bt3central.com/showthread.php?t=7408

I found the timer switch, but have been wondering about multispeeds. Where did you get your speed switch? Is it variable (by how far you turn it), or have fixed settings?

I am gonna have to build mine as a floor model (maybe a downdraft table, maybe a Bridge table), as my ceilings in my shop (basement) are 6') So the multispeed part could help.

Thanks

[Dirk Lewis]

I found the timer switch, but have been wondering about multispeeds. Where did you get your speed switch? Is it variable (by how far you turn it), or have fixed settings?

I am gonna have to build mine as a floor model (maybe a downdraft table, maybe a Bridge table), as my ceilings in my shop (basement) are 6') So the multispeed part could help.

Thanks

Hi Randal - I'm thinking along the same lines as you and am looking at making a floor model as well. Just started looking for plans today, so will repost if I find I good set of plans to share.
D

[Bill White]

I mounted an AC blower in the ceiling of the new shop to act as a filter exhaust fan. I have an ambient filter as well as a dust collectro. Just thought that being able to exhaust would add to the effect.
Bill

[Dirk Lewis]

I mounted an AC blower in the ceiling of the new shop to act as a filter exhaust fan. I have an ambient filter as well as a dust collectro. Just thought that being able to exhaust would add to the effect.
Bill

Hmm, hadn't thought of that....off to the garage attic to see what kind of room I have up there for some sort of exhaust setup.

[glenn bradley]

Any pitfalls I need to be aware of if I build one? Thanks very much.

I should have left more space available between the last inbound filter and the fan. Most plans call for this. I wasn't paying attention and am restricting my blower somewhat from being as efficient as it could be. I plan to re-build.