# Exhaust Fan vs. Air Filtration



## nathanvaughan

Hi, I have a 900 sq. ft. work shop with dust collection at the source for most tools. I do use sanders, wire brush, etc.. on re-claimed wood that is dirty; I need a way to control the dust/dirt. 

I am considering either a 36" dayton exhaust fan or a portable air filtration system to move around the shop. Any ideas on which would be most efficient?

Thanks.


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## Jim Frye

I vote for both. I have a shop built filter that runs 700/1,000 cfm and uses 4" thick computer room filters. It sits on the floor and has floor and ceiling outlets. I also have a small exhaust fan for finishing fumes. I also have dust/chip collection for all of the powered tools. My shop is a little over 2,000 cu. ft (12x22x8).


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## FrankC

Perhaps you need to step back and look at the big picture, what is that dirt you are removing and is it worth the risk?


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## Catpower

If you aren't heating or cooling your shop, exhaust would be the easiest, but it you are build something like Jim did. Look on the web for form 10 muffin fans the kind they use to cool computers, build a wooden box and make a slot for a filter.

The one I built has 2 1000 cfm muffin fans in it with a 20x25 pleated filter, if you treat the pleated filters kindly you can blow them out numerous times before replacing


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## woodnthings

*The 4 types of dust managment are ......*

Point of source pickup by Shop Vac.
Point of source pickup by Dust Collector.
Airborne dust filtration by overhead unit.
Air exchange by exhaust fan.

For proper air fiitration you need all 4, depending on the operation underway.
Sanding makes the greatest amount of fine dust, so it's best to get it right off the machine before it can get airborne. 
Sawing and routing makes a combination of fine dust and very small dust chips whether it's a miter saw, a table saw or a bandsaw. The dust ports on most of those machines are NOT very effective and you may need a combination of the shop vac and larger dust collector. Even then, it's not a given that you will get all the dust and the overhead air filter is needed.
Planing and jointing make larger chips and usually a large dust collector is fine for those operations.
When the shop gets too much airborne dust to filter, it's best to just exhaust the contaminated air outside.

In my shop I use all 4 types, but being lazy I often forget to use one of them for just a quick pass. The bandsaw is a "sleeper" when it comes to making dust and it generates more than you might think. My bandsaws have 2 ports, one 2 1/2" under the table for a shop vac and one 4" at the bottom for a dust collector. It does a fair job, but not totally efficient. 

Some woods have an obnoxious smell when cut into, others have a more pleasant odor. Some are also toxic, so you want to get that dust collected immediately. 
Some people are more sensitive to certain wood dust than others, and begin sneezing and coughing when exposed. You need to establish your own personal limits and work to eliminate the offensive dust. Bill Pentz has an entire website devoted to dust collection from both a medical and engineering point of view. It is worth reading for certain:

http://billpentz.com/woodworking/cyclone/index.cfm#index.cfm

http://billpentz.com/woodworking/cyclone/cyclone_plan.cfm#air_volume

It goes without saying that a personal respirator will reduce the intake of contaminated air to harmless levels.


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## Steve Neul

As far as I'm concerned dirt is part of woodworking. Anyway with winter here I don't think you want the exhaust fan. It would suck the heat out with the dust.


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## michaelpugh

I use a ducted dust collector, air filtration (when needed), and a dust mask when needed.


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## VIFmike

It also depends on where you do your main work. If you have a central work table/bench in the middle of the shop having a fan there or a dust collector there would work great. It also depends on how much room you have to move around a mobile system. I would vote for fixed system mounted somewhere above and ducted out.


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## dumbclub

Remember that for the air to be exhausted out of your workspace, you need to also direct the flow of incoming air. In spraybooth lingo, it's called "make up" air. If you can have the make up air source on one side of the shop and the exhaust opposite it, you should get good airflow.

In my shop, the dust collector is located in a separate room with a filtered return air duct that brings the air (and heat) back into the work area.


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## nathanvaughan

Thanks for all the replies! I just bought a jet air filtration unit (AFS 2000) and it makes a substantial difference. I think I'll try and install an exhaust fan for summer time but am happy with the results so far.

Nathan


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## Toolman50

nathanvaughan said:


> Hi, I have a 900 sq. ft. work shop with dust collection at the source for most tools. I do use sanders, wire brush, etc.. on re-claimed wood that is dirty; I need a way to control the dust/dirt.
> 
> I am considering either a 36" dayton exhaust fan or a portable air filtration system to move around the shop. Any ideas on which would be most efficient?
> 
> Thanks.


Most fans are set on the floor and most filtration system are hung from the ceiling. 
When converting the fan as an air filtering system, I think it would need to be hung from the ceiling to filter the air you breathe vs stirring up all the dust on the floor. 
A fan will stir more air. Even on low, I think the fan will pull more air than a filtration system. Nice maybe in the heat of summer but not in winter. 
The filtration system may be quieter???


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## Pineknot_86

I use a box fan with a furnace filter held in place by a bungee cord. SWMBO saw this on a HGTV show once. Rarely use it as my Shop Vac handles what dust I generate.


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