Outdoor Dust Collector Questions

[Chris Jackson]

Thinking of moving my 2hp single stage dust collector and cyclone separator outside of my shop. This would be accomplished by boring a hole through the cinder block foundation wall and routing 4" sch 40 pvc into the existing shop system and running a small electrical conduit for the 220v cordage. I would of course seal the penetration with expansion foam and/or monkey *&%$, and dress it with an escution.

Does anyone have experience with this? I have several concerns before getting started:


Are there significant building/construction code concerns with a 4-1/2" hole in my cinderblock foundation wall? (I already have 3" dryer vent hole in one location and I would assume that's not a problem, so how big is too big?)
What to do for a shed type construction outside to house the collector and cyclone? My current plan is to build an elevated "shelf" with 100 lb. shelf brackets mounted to the foundation wall and build a small slant roof shed to house the equipment, keeping it off the ground and out of the rain/snow. I would do a couple of expanded metal or Louvre'd vents for adequate flow...at least a few square feet to support adequate CFM. Concerns there are how do I determine vent size? After that, how do I build the vents large enough and not let in the bugs/birds and weather?
Any advice is appreciated...this would be such a helpful shop project for the added floor space, noise reduction, dust reduction, etc... Just want to make sure I get it done right the first time.

Thanks,
Chris

[Bob Riefer]

Not a code inspector's, engineer's, builder's point of view (i.e. just a common guy's opinion):

I have many neighbors with block walls that have 4" vents through them, so that wouldn't concern me.

I wouldn't suspend the DC on a shelf as it seems like extra work and it will relay vibrations into your building. For something that small, I'd probably just dig down a couple inches for some gravel, and put formed blocks (e.g. cinder blocks without the holes) on top as my "floor". I don't even know that I'd bother with a vapor barrier in this case.

For the surround, I'm not sure, but I would guess the unit needs to breathe. But others will chime in on that.

Knowing when your collection bin is full is more difficult when it's outside, just keep that in mind.

[David Gutierrez]

A 4.5" hole in the block wall should not be a problem. The "shelf" brackets do not sound like a good idea. Why not build the shelf/shed from 2x lumber?

[Dan Friedrichs]

A few thoughts:

1) If you're going to make a hole, why not just make it 6"? Your 4" PVC is probably quite the airflow restrictor, even with a 2HP blower.

2) Since you're pumping air out of the shop, you need to make a vent to allow fresh air back into the shop.

3) Do you really need the cyclone? Are you just blowing all the dust outside? If so, perhaps you can forgo the cyclone.

If the blower is TEFC (totally enclosed fan cooled), you may not even need to worry about building any sort of shed around it. It should be just fine getting a little wet.

[Lee Schierer]

Just bear in mind that the cfm of the blower will be removed from your shop each minute it runs. This will deplete your heat and A/C for your shop. If you don't have a large enough air inlet you may suck combustion products back into the room from your heater if it is gas, oil or wood burning.

[Chris Jackson]

Great points regarding air removal from the shop. On that note my shop is in a 2 car garage and I am installing carriage doors to replace my roll ups. When I do that Modification I will include a 1 sq ft. vent door in each side that can be opened to allow for air circulation.

Sounds like no one has any concerns with 4-1/2" hole in the block. GREAT!!

Dan, Modern dust collector motors are far from true TEFC, though they are rated as such. After 20 years in the nuclear industry I've seen many a TEFC bite it from much less than a few months of outdoor exposure. Also, my filter bag has been replaced by a full pleated filter cartridge which would not survive a rain storm or snow storm.

My thought is a full enclosure of general 2x4 construction with a slant roof...sounds like the votes are against mounting it on a shelving system...the gravel and block floor sounds good as an alternative.

As for 6" dust pipe...my entire system is run with 4" now...I've already got plenty of 4" available, I'm happy with the current performance, and I won't be adding more than an additional 6' of pipe run to the system...I see no need for the added expense.

As for the cyclone...I cannot imagine anyone who has 5 or 6 major machines and does not have some type of cyclone...I'd be going through dust bags like Carter had liver pills.

Thanks everyone for your inputs they are greatly appreciated as always!

[Devon Shannon]

I have a DC outside conected with 6" HVAC. I believe the metal duct-work outside is drawing considerable heat from the inside. Just metal in the pipe now, I'm not talking air-movement. Some of the heat conduction probably could have been avoided by using PVC or wrapping the exterior of the pipe in insulation. Just something to consider when installing.

[Chris Jackson]

Thanks for the tip devon...I plan on using PVC, and insulating with expanding foam.

[Jim Becker]

Chris, I see no issue with your plan for the hole, etc.

Do consider that the maximum CFM you can cram through a 4" duct is about 300-350 CFM. For this reason, I suggest that while you're going through the trouble of putting a hole in your block wall, make it big enough to support the larger duct for a future upgrade. Most likely, your current blower can actually support 6" if you take off the flange that steps it down to 4". Where you'll really benefit from the increased performance (6" duct can flow up to about 800 CFM) is with your planer and hard to collect from machines like table saws and band saws.

And yea, I'm a cyclone believer. 'Have been since my first one back in 2000.

[George Bregar]

Just bear in mind that the cfm of the blower will be removed from your shop each minute it runs. This will deplete your heat and A/C for your shop. If you don't have a large enough air inlet you may suck combustion products back into the room from your heater if it is gas, oil or wood burning.

That's what I thought, but then came the conclusion that only the CFM applicable to the port(s) I had open would be removed from my shop. Was I right and now wrong, or wrong and now right? :confused:

[Jim Beachler]

I have my cyclones outside with 6" pipe going through a block wall. What I did was keep the motor on the inside and turned the cyclone into a push. The exhausted air from the cyclone just goes into the air. As far as collection, I just attach a heavy trash bag to the pipe hanging down. I do not cover this with any shed as just the cyclone and bag are outside.

concerning 4" vs. 6" pipe through the wall. My suggestion is to 6" as if you decide later to increase size of your ports, you don't have to redo the wall. Maybe have the part after the collector in 6". It is not very expensive to do it once and not have to redo it.

[Jeremy Greiner]

One thing to throw in that I've read, and didn't see it mentioned is you need an a way to cycle air back into the shop. If you have all the windows/doors closed etc and the dust collector is sucking air out of the shop this can cause pressurization problems.

I don't have my DC outside, so I have no experience in this, just something I remember reading.

-jeremy

[Dan Friedrichs]

Also, my filter bag has been replaced by a full pleated filter cartridge which would not survive a rain storm or snow storm.

Wait, what? If you are moving the DC outside, and thus venting the filtered air to outdoors (and bringing fresh new air in through a garage door), why do you need a filter?

Why not just run the dust through the cyclone to remove the big chunks, then let the cyclone exhaust blow into the air? Whatever tiny amount of dust is left will never be visible. Isn't the whole point of outside venting to avoid the need for filters?

[Mike Hollingsworth]

I'm considering doing this venting outside thing. Are there any noise issues for neighbors?

[Neil Brooks]

I'm considering doing this venting outside thing. Are there any noise issues for neighbors?

It's hard to imagine that the noise would be too much different than a dryer vent.

Even with a vent hood, pointing downward, my bigger concern would be whether or not an obvious dust cloud was emanating from my house.

[George Bregar]

Even with a vent hood, pointing downward, my bigger concern would be whether or not an obvious dust cloud was emanating from my house. No dust cloud with a separator.

[David Giles]

I converted a 1.5Hp dust collector into a cyclone located outside. I would second the recommendation to run 6" header and put it where you won't trip over it. The cyclone and blower set on a plywood hole supported by a 2x4 frame. Not pretty, but serviceable. Everything is under a metal awning to keep rain off. The discharge line free vents outside the awning lip. No cartridge and no major dust emitted unless I forget to empty the bag.

[Dan Friedrichs]

No dust cloud with a separator.

+1. I just put a Thien baffle inside the bag ring of my HF DC, and replaced the top bag with a connection to a 6" vent leading outside. My vent points down to the ground, about 4" above grade. I recently cut a bunch of MDF, and we had snow on the ground, and the only thing visible was the slightest tint of brown dust on the snow - barely visible.

[Neil Brooks]

+1. I just put a Thien baffle inside the bag ring of my HF DC, and replaced the top bag with a connection to a 6" vent leading outside. My vent points down to the ground, about 4" above grade. I recently cut a bunch of MDF, and we had snow on the ground, and the only thing visible was the slightest tint of brown dust on the snow - barely visible.

At the risk of asking a silly question .... why won't the exhaust vent ... be ... exhausting ... all the fines that still fill up my collector bag after my chip separator ?

Or is is that ... they will go out the vent, but ... rarely/never in such quantities at any given time that anybody would notice ??

[Chris Jackson]

Sounds like a resounding call to plan ahead for 6"...which I don't disagree with. My DC is a Jet 2 HP unit and has a 6" primary port if I remove the Y fitting. I could certainly run 6" from the DC through the hole and hook it up the existing 4" piping run with a reducing fitting, and there would be some benefits immediately as well as some future ones to gain. Concerns are:

-my cyclone only has 4" ports, and that would either require reducing fittings (which negate the benefits of larger piping, as the K value of these restrictions are still at 4" thresholds), or buying a new cyclone (which I can't affort). Cyclones with 6" ports don't come cheap and I have yet to see a trash can type unit with 6" connections.

-now I would have to consider a 6" hole in my cinder block wall...that's a mighty big hole! even assuming no code structural issues (not sure that's the case) that certainly presents some resale issues with my home.

Any thoughts?

[Dan Friedrichs]

At the risk of asking a silly question .... why won't the exhaust vent ... be ... exhausting ... all the fines that still fill up my collector bag after my chip separator ?

Or is is that ... they will go out the vent, but ... rarely/never in such quantities at any given time that anybody would notice ??

I suppose some fines still end up outside, but I think the air velocity just throws them so far and they're so light that they get easily picked up by the wind and carried away (or just drift away).

[david brum]

Instead of a trash can separator or cyclone, you can install a Thien baffle inside the inlet ring on your Jet DC. These work absolutely great and will cause much less air loss than you'd get with either other option. They are easily made with scrap plywood or mdf. I've used one on a 1.5 hp Jet and currently have two on a 3 hp DC. I don't notice any drop in suction with them installed, although I'm sure there is some. With a baffle, you don't have to worry about ducting size.

A quick search shows this link http://www.cgallery.com/smf/index.php?topic=100.0