Air filter / Air flow question

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Forum topic by natrous posted 11-08-2010 10:26 PM 1085 views 0 times favorited 2 replies Add to Favorites Watch
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65 posts in 2784 days

11-08-2010 10:26 PM

Topic tags/keywords: air filter blower

I am planning on getting or building an air filter for my basement-shop. Since there’s no walls or anything dividing the space, the entire basement needs to be used for sizing the blower.

My question is, how fast do I really NEED to circulate all the air in the shop? Most plans I see call for circulating in 5 minutes – which means a pretty big blower for a modestly sized basement space (between 6000 and 6500 cu ft, which requires a 1200-1300 cfm blower for 5 minutes).

I assume if it takes too long to circ the air, then more dust will settle instead of getting filtered – but does anyone have a good idea about where the cutoff should be? Can I do a 600cfm blower and run it for 10 minutes and still have good results? What about a 300cfm for 20 minutes?

Any thoughts are appreciated.


- Nate

-- I do not like work even when someone else does it. - Mark Twain

2 replies so far

View Mark Shymanski's profile

Mark Shymanski

5621 posts in 3712 days

#1 posted 12-18-2010 04:45 PM

I would guess that after a certain amount of time you will not re-entrain the dust in the air no matter how big your blower is (unless you’re using a leaf blower LOL!). My understanding is the sizing is to eliminate airborne particles whilst they are airborne…this is why it is so important to effectively catch the dust at the source as opposed to trying to recapture it once it is in the air.

I’ve seen videos where guys are wearing dust masks in their shops instead of (or perhaps as well as) filtering the air. A precaution I could see using if you had sensitivities to the particular wood being milled.

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

View TechRedneck's profile


768 posts in 2856 days

#2 posted 12-19-2010 03:34 AM

I noticed you posted this 40 days ago but here is my 2 cents worth. I have a similar situation with a garage/basement workshop and actually stopped woodworking until I was able to get the dust under control. I have 1632 sq. ft. I would recommend a DC system to catch as much dust and chips at the source like Mark suggested.

My first attempt was a Clear Vue mini cyclone and large shop vac dumping into a trash can. This thing works like a champ and has a high velocity flow with less volume using 2.5” piping. Second thing I did was get a Delta DC system and piped in the big tools. I plan to replace the bag with a canister but it works.

Then to clean the ambient air ( and save money) I got a hold of a used furnace fan that has three speeds for $45 bucks (1200+ CFM) and built a down draft table. This table serves as an out-feed table for the TS and sanding/hand router station. I put a total of four filters in it. First set to catch the big stuff and a second more expensive set for the fine stuff.

I put a timer on it and run the thing when using the table saw and SCMS to catch the small amount of airborne dust before it settles. If you build it yourself and do it right, you can have a huge amount of air flow through a lot of filters and get dual use out of it. Encased in a cabinet of 3/4 ply it is quiet to boot.

-- Mike.... West Virginia. "Man is a tool using animal. Without tools he is nothing, with tools he is all.". T Carlyle

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