Dust Collecting vs. Dust Exhausting

[Richard Elliott]

If you have the option to exhaust dust, is it better to do that than try to collect it? I have a 1hp cheap blower set up with a trash can type 1st stage and then I just duct the air outside. I have been considering upgrading the DC and adding fixed duct work to the shop, and wonder if I need to invest in a dust collector with 1 micron filtration, or just a larger blower and continue to exhaust the dust out side. The blower, without a filter bag, is pretty capable, not sure if a 2hp with a 1 micron bag is going to be any more efficient than the 1hp with no filter bag and direct exhaust outside.

[Anthony Whitesell]

Dust collection works on CFM. If you can exhaust outside, then you provide less back pressure and will up your CFM. The draw backs to exhausting are two fold. First, obviously it can be messy. Secondly, you will be exhausting any heat or cool air from the shop to the outside. If you would like to retain you heated/cooled air then a filtered system in the shop is the way to go.

[Chris Parks]

Getting dust out of the workshop is always better. Collecting it requires maintenance, exhaust it and it is gone.

[Matt Benton]

I would suggest using Phil Thien's baffle to capture the larger chips that could damage the impeller. Other than that, you should be able to exhaust outside. The fines that the baffle doesn't capture shouldn't make much of a mess...

[Jim Becker]

Richard, part of the "answer" to this question revolves around what geography you live. Exhausting is absolutely the best overall, IMHO, but not when it also exhausts expensive heat or air conditioning results to the atmosphere. My compromise, if I could physically accommodate it (I cannot due to exterior elevations), would be to have my cyclone located outside, either in a shed or semi-protected and just bring the filtered air back inside. That would cut noise and remove the single biggest creator of "free dust" in my shop...the act of emptying the 55 gallon fiber drum. Despite only physically moving the drum across the floor and out the door to the waiting tractor, there is still a lot of fine material that ends up in the shop air just from disconnecting the lid and moving the barrel.

[Chris Parks]

I suppose I don't have to worry about climate and the loss of air from the workshop. If I did I would return it after I slowed the air down through a large cavity. The reason for that is the dust falls out of air that is slow moving, so run it through a cavity or trap room might be a good term, slow it down anf then return it through a big filter. This cavity would ideally be emptied from the outside. Always remember that dust only stays suspended in fast moving air, slow it down and half your problems are fixed.

[Frank Hagan]

I remembered reading on Bill Pentz's site (http://billpentz.com//woodworking/cyclone/Introduction.cfm) that venting outside is the best solution. I think most commercial shops even have their dust collectors outside. If you can vent outside, I think that would be the best solution.

Most of us have to collect the dust somehow, to prevent the neighbors from taking up torches and pitchforks against us.

[Tom Veatch]

...I would return it after I slowed the air down through a large cavity. The reason for that is the dust falls out of air that is slow moving...

This is quite true, but it is also true that the fine particles, the ones that cause the most respiratory damage and settle out as dust nibs on freshly finished projects, can remain suspended in still air for quite a long time. Although using a drop box will remove the larger particles, it will not remove the fines unless the air exchange rate inside the box is very low - very large box, very low flow rate. Otherwise, if you're going to return the air to the shop, it should be filtered.

[Rod Sheridan]

I remembered reading on Bill Pentz's site (http://billpentz.com//woodworking/cyclone/Introduction.cfm) that venting outside is the best solution. I think most commercial shops even have their dust collectors outside. If you can vent outside, I think that would be the best solution.

Most of us have to collect the dust somehow, to prevent the neighbors from taking up torches and pitchforks against us.

Many industrial cyclones are located outdoors, yet return the air back into the building.

When I worked in a woodworking industry we had a large cyclone (about 50 HP) that returned air back into the plant through the baghouse room.

Exhausting 30,000 CFM of heated air in the winter would have been very expensive.

regards, Rod.

[Frank Hagan]

Many industrial cyclones are located outdoors, yet return the air back into the building.

When I worked in a woodworking industry we had a large cyclone (about 50 HP) that returned air back into the plant through the baghouse room.

Exhausting 30,000 CFM of heated air in the winter would have been very expensive.

regards, Rod.

Like Chris, I don't have to worry about heated or conditioned air, so the large filtration required to meet the air quality standards for workplaces isn't needed. (I suspect that Canada Health's requirements are at least as stringent as the US, or that they are the same standard since so many of our codes have been "harmonized" over the years). I do have to be concerned about the mess, and possible harm to kids playing outside. Looking at the ClearVue Cyclone site, it doesn't appear that much ends up on the filter anyway, but even so ... if you can exhaust the air outside, even if filtered, that is the best scenario. I'm not sure our home-duty cyclones from Grizzly, Oneida-Air, ClearVue or Penn State would meet that standard all the time. If we can't see the dangerous stuff, how do we know when our filters are compromised and passing it through?

The cabinet shops I see around here appear to have the air vented outside, but I could be missing it. They do have huge cyclones outside their shops. I'll have to take a closer look someday.

[Michael Schwartz]

It is also good to run an overhead filtration system in your shop as well as a dust collector to get the rest of the dust that ends up back in the air.

[Phil Thien]

Exhausting 30,000 CFM of heated air in the winter would have been very expensive.

regards, Rod.

It would make opening exterior doors a challenge, too. :p

[Ed Ragim]

Hi, gays!
I want exhaust the dust out my shop too, but not completely outside.I have the small room side by side with shop, somethig like pantry (1m x 1m) and think to use it.
Have I make some holes in the pantry door for part of dusty air get out anyway?
Have I switch blower on and open the door or window?
I very hope my question is undestandable, sorry my horrible English!

[Chris Parks]

I would get some coarse filters like are used in a spray booth and exhaust the air through them. Put them up high so the material tends to drop out in the cavity and settle to the bottom. Make sure you can empty it from the outside of the building.

[Phil Thien]

Wouldn't that create too inviting an environment for varmints and insects?

[Chris Parks]

Wouldn't that create too inviting an environment for varmints and insects?

They make the world go round.:) If it did we would have our workshops invaded with the mess we don't clean up?? I have really never given it any thought Phil. A pet snake might help?:eek: