Venting the dust collector outside?

[bob_mp]

Hi,
I am planning on adding a dust collector to my new shop for the woodworking tools. I am giving thought to mounting the dust collector outside for reasons of space and to (potentially) avoid the fine dust that might escape the filter. I'm located in the Bay Area, CA. The shop will be heated in the winter; that said, the climate is pretty mild here.

A couple of questions:

1. Does it makes sense to put the dust collector and dust bin outside?

The arguments for doing so are that all the dust gets blown outside and that it saves space inside the shop. The downsides are that it will **** the heated air out of the shop in a big hurry and that it's going to be some extra work to weatherproof both the penetration in the wall and band the dust collector itself to protect it from the elements.

Are the filters good enough (assuming I'm willing to spend the money) so that the air quality isn't a big concern?

2. Does it make sense to get a portable dust collector so that I can both move it around and decide where I want to vent it?

Thanks,
Bob

 

[Randy in Maine]

I bought a taller filter bag for the fine dust from these guys and it was really an improvment in my 1.5HP Delta wall mounted dust collector....

http://www.americanfabricfilter.com/

 

[kbs2244]

Check out the wood working sites.
Outside dust collecting installs are not uncommon.
Even in much colder New England.

Just make sure the system of collecting pipes is grounded to prevent static sparks and fires.
They talk about it a lot.
With reason.
I have walked through the ashes of shops where the guy thought the danger was overstated.

 

[buddyboy]

just remember if you blow the air out of the building you'll need to make that air back up.

if it were me it might be worth the extra expense to run 2 sets of pipes to each machine, fresh air intake and dusty air exhaust, to minimize conditioned air loss.

 

[pattenp]

just remember if you blow the air out of the building you'll need to make that air back up.

if it were me it might be worth the extra expense to run 2 sets of pipes to each machine, fresh air intake and dusty air exhaust, to minimize conditioned air loss.

Care to explain how that would work without reducing the vacuum?

 

[TerryH]

I would not vote for the portable DC. My experience has been that you will get much better performance with a larger stationary unit. I highly recommend a cyclone over a regular DC. Today's cartridge filters are so good that I just don't see any advantage to exhausting the discharge outside.

 

[TerryH]

Check out the wood working sites.
Outside dust collecting installs are not uncommon.
Even in much colder New England.

Just make sure the system of collecting pipes is grounded to prevent static sparks and fires.
They talk about it a lot.
With reason.
I have walked through the ashes of shops where the guy thought the danger was overstated.

Really? I'd certainly be interested in seeing documentation.

 

[Texican]

I would not vote for the portable DC. My experience has been that you will get much better performance with a larger stationary unit. I highly recommend a cyclone over a regular DC. Today's cartridge filters are so good that I just don't see any advantage to exhausting the discharge outside.

Totally agree, with the latest filters used with a cyclone system, mounting the unit outside is unnecessary. Only reason I would mount the unit outside is if space was an issue.

 

[Tim The Tool Man]

Just make sure the system of collecting pipes is grounded to prevent static sparks and fires.
They talk about it a lot.
With reason.
I have walked through the ashes of shops where the guy thought the danger was overstated.

Sorry, I don't believe it. I might be wrong but I would be willing to bet good money that there has never been a documented case of home hobbyist shop fire caused by a static shock in a dust collection system. Yes in an industrial setting with the exponentially higher volume and pipe diameters, it is a real issue. Not in a home though. That said, you will not hurt anything by grounding your pipes.

As to putting the collector outside, no real down side to it other than, as has been mentioned, you will create a negative pressure environment in your shop real quick if you don't mount an outside air intake somewhere. I have seen a back draft flapper type set up that introduces outdoor air directly into the HVAC system's cold air return ducting. It only opens if there is a negative pressure in the shop and then conditions and filters the new air through the HVAC system.

Totally agree, with the latest filters used with a cyclone system, mounting the unit outside is unnecessary. Only reason I would mount the unit outside is if space was an issue.

I would mount mine outside for the noise it creates alone! ...but I would still filter the exhaust even if I put my collector outside for environmental reasons.

 

[TerryH]

Sorry, I don't believe it. I might be wrong but I would be willing to bet good money that there has never been a documented case of home hobbyist shop fire caused by a static shock in a dust collection system. Yes in an industrial setting with the exponentially higher volume and pipe diameters, it is a real issue. Not in a home though. That said, you will not hurt anything by grounding your pipes.

+1000 on what Tim said.

 

[Albiemanmike]

If you want the defacto source for any and all dust collector information go to this site and be prepared for some serious reading he has researched the subject to death because he was dying of dust exposure and his doctor told him he had to quit or figure out a way to keep himself from being slowly killed by the minute micron dust particles. They are what is dangerous the stuff you cannot see.

http://billpentz.com/woodworking/cyclone/

 

[Texican]

Compared to the other tools in my shop, the dc is quiet. Plus my mother in law stayed with us for awhile and anything is quiet compared to her.

 

[Voi]

Have you checked to see if you're allowed to exhaust your dust collector outdoors? From reading various wood working forums it seems in many areas this is not allowed.

I have read, however, that many still put their DC's with filter in an outdoor closet or shed to both cut down on noise and to avoid re-circulating the super fine particles back into their shop. So to answer question 1, yes I think it's worth it, especially in your more mild climate.

I would read up about the newer filters on Bill Pentz's site and WW forums. Many people are buying air quality testers and doing their own research.

A portable DC that is moved from machine to machine does allow for shorter runs of pipe and one then doesn't need as powerful of a machine. Some people still exhaust their fine particles outside doing this with a long run of flex hose.

I think the ideal setup would be a three phase DC in an outdoor shed. Run it on a VFD and you can fine tune the flow if chips are making it through the separator. If you're allow to exhaust the dust outdoors, then no filter. If not allowed, then use a filter but the particles that get through aren't in the shop.

 

[Angelfire]

If you want the defacto source for any and all dust collector information go to this site and be prepared for some serious reading he has researched the subject to death because he was dying of dust exposure and his doctor told him he had to quit or figure out a way to keep himself from being slowly killed by the minute micron dust particles. They are what is dangerous the stuff you cannot see.

http://billpentz.com/woodworking/cyclone/

He has definitely done his homework. I've been in touch with him numerous times asking questions and such and he's always been great at responding. His assertion is that to get all the fine, unhealthy dust out of the air, requires a minimum of 6" duct (for most machines) and significant velocities. None of the so called "dust collectors" on the market can match his designs and they don't clear the air of the small dust. Yeah, they'll make it seem as though they are keeping the place clean but really aren't doing what they should be.

An option for the OP is to run duct outside, place your filters there, then pipe back inside as a return air. You'll lose a little heat obviously but not nearly as much as just leaving the cleaned air outside.

 

[Regnar]

My dust collector is in a leanto on the outside of my garage. I still use a cartrage filter and to be honest I sometimes think I might just take it off. The only reason I dont is my neighbors are within 100ft and its not to bad to clean it.

I dont condition the air in my garage but I will tell you the Dust Collector helps me during the summer to cool down the garage by getting rid of all built up hot air. I just crack the garage door a little run it for a few minutes and the temp goes down. It makes me think a whole house fan would work very nice and cost a lot less to run.

 

[drmarkr]

If you want the defacto source for any and all dust collector information go to this site and be prepared for some serious reading he has researched the subject to death because he was dying of dust exposure and his doctor told him he had to quit or figure out a way to keep himself from being slowly killed by the minute micron dust particles. They are what is dangerous the stuff you cannot see.

http://billpentz.com/woodworking/cyclone/

You damn well better read this.....and then put your collector outside, if at all possible.

There really is no way to completely filter all the particles that can cause harm.

 

[elav]

I'm also in the Bay Area and use my garage for multi-use (including woodworking). I have all my woodworking machines on dollies that have kickup wheels and I roll the machines outside the garage, kick up the wheels so the machines are stable and use a portable dust collector and a dust mask. Keeps the garage dust free and is a fairly good compromise with the number of rain days we get here.

 

[icecactus]

Check out my garage build in my sig to see how i mounted my cyclone dust collector.

I considred mounting it outside but my neighbors are 10ft away from me, and i figured they would not appreciate the noise/dust blowing into their house.

 

[Toolfool]

My cyclone is inside the shop and vents through filters. Didn't want to lose the heat. With the remote, it only runs while a machine is running, so the noise is bearable. I also purchased the system designed by Bill Pentz, clearvuecyclones.com .

 

[DPelletier]

- 1) Yes, it makes sense to put the collector and bin outside if you can (and local codes allow). It's quieter, saves space and the indoor air qualitiy is better not re-introducing the filtered air to the space.

- 2) Every collector, filter and system is different so generally whether the filters are "good enough" depends on the situation. One thing is certain; NO filter setup is going to be as good as exhausting the air outside and replacing it with uncontaminated outside air.

- 3) Portable collectors are typically inferior, don't flow enough, don't filter well enough and re-introduce the air into the space.

I install industrial and institutional fume and material extraction systems and for wood dust collectors, I design to 4000 FPM. We DO install recirculating systems as well, but they are usually high-end, large systems that have superior filtration to anything the hobbyist is likely to purchase which is why I would recommend exhausting the air to the outdoors.

HOWEVER, the big proviso here is that you need to ensure that your workspace will not have other issues under a negative pressure (i.e. no non-sealed combustion gas fired equipment should be used for eg.) and you also need provision for Make-Up Air as well as allowing for the tempered air loss.

Dave

 

[ODIS]

This is my installation in the standalone garage/shop:
http://www.garagejournal.com/forum/showthread.php?t=149658&page=3

Post# 53

Ody.

 

[Tim The Tool Man]

...and this is mine in a back room with filtered return air ducting to my shop: Thien Seporator

 

[kb2tha]

FWIW, I would suggest the portable indoor units (perhaps 2) and add to that a good ceiling mounted unit that is designed for removing small suspended particles. Set the ceiling unit up on a timer switch and it can run after you leave the shop as well. I have two of these units that I built using a furnace blower and squirrel cage. Both work great. I also just recently purchased a retired school commercial ceiling unit. Much larger and will move much more air. I will mount this in my new woodshop once we build.

My background includes 37 years as an Industrial Arts & Voc Ed teacher (carpentry/cabinetmaking) where over the years we used varying systems, some outside but most inside.

 

[TerryH]

Just buy or build a good cylone with Wynn filters and be done with it. I worked extensively with Bill Pentz during the design and instruction manual phase of his cyclone design. I did the hands on portion of the plan working out the individual pieces and methods of construction. I've built many of them since. It's not complicated and is quite a rewarding project. If you don't want to build one then just buy a good cyclone of the proper size for your space and equipment with good filters. But be aware that there is much, much more to effective dust collection that just the collector. You have to have properly sized and designed ducts and hood on the machines that are efficent enough to capture the fines. The idea of dust collection in general is to not put the fine dust into the air in the first place. A good cyclone with good filters coupled with the proper ducts and hoods will accomplish that and you'll be much happier in the end.

Before I built my first cyclone I had mutiple portable units/air cleaners and used them all the time. I would spend a day working in the shop and the next day there would be a layer of dust on everything which told me that even with everything that I was doing, the fine dust was not being captured or was not staying captured. No such issue once I built a cyclone, installed a good ducting system, and upgraded my collection hoods. It's worth your time if you are worried about dust and it's effects on your health.

 

[PECVD2]

Terry I would like to see your collection of upgraded hoods and if possible videos of them at work. Your place looks cleaner than most kitchens I have been in.

I struggle controlling the dust with my belt sander, table saw, mitre saw and even my band saw.
They are older and were never set up for a DC system so all of mine are retrofitted DC components (mostly homemade).

Anyway I would like to see your hoods in action, please show us how it is done!

 

[PECVD2]

TTTMan, your inlet and outlet hose to your Thein appears to be similarly coated with fine dust. Is the Thein just for removing the large particulate or am I missing something?

 

[TerryH]

Terry I would like to see your collection of upgraded hoods and if possible videos of them at work. Your place looks cleaner than most kitchens I have been in.

I struggle controlling the dust with my belt sander, table saw, mitre saw and even my band saw.
They are older and were never set up for a DC system so all of mine are retrofitted DC components (mostly homemade).

Anyway I would like to see your hoods in action, please show us how it is done!

I have lots of pics but no video. Most of what I have done is increase everything I possibly could to 6" hoods. I frequent the local HVAC supply house and adapt lots of HVAC boots to my various machines. There is a link to my shop photos on in my signature line. Most everything is there. I'll show a few here so you get the idea.

I'll start with the table saw. 2 mods here. The first is to simply use an 6" HVAC take off in place fo the factory 4" outlet. These take offs are super cheap and available at any HVAC supply or at most home centers.

I just cut a 6" hole with the jig saw and screwed the take off to the clean out door.

I made an overhead hood/cover for the blade as well. It has 4" plumbed to it.

Here's the hood for the planer. Another HVAC register boot just cut and mated to the original planer hood. 6" plumbed right to this hood gets nearly every speck but be warned, this much air moving through the planer is very loud!!

Very simple upgrade to 6" on the jointer very similar to the tablesaw..

Sliding compund miter saw is one of the toughest. Here's what I use. Not perfect but works reasonably well.

4" to the router table..

None of this is complicated. Anyone can do what I've done. Effective dust collection is all about moving air. Most of the performance gains that I've seen are simply increasing the duct diameter at the hoods to 6". With that being said, you have to have a collector that has enough guts to produce enough air movement to be effective which means 4000fps of air movement minimum in the duct with a minimum of about 1000 cfm at the machine. That means that the ducts and the hoods have to allow for that much air to pass through or even the best collector won't perform. In my opinion, a 3 hp cyclone with 6" ducts is the minimum. Mine is 5 hp with a 17.5" straight blade impeller and I have all 6" ducts only reducing to 4" where absolutely necessary. My system produces a little over 3000 cfm and has nearly 8000fps of duct speed. That is overkill but I wanted to see just what was possible with Bill's design.

 

[Angelfire]

Terry,
Regarding your cyclone, which motor and blower did you use? I purchase a motor and an airfoil based on Bill's advice several years ago only to find out the airfoil couldn't handle the pressures in the system. So I'm back to square one. I won't be working on this for some time but thought I'd see what you used. I'm guessing a 5hp motor.

Funnily enough, most of my equipment matches yours (ie. tablesaw, jointer, planer, etc...).
Cheers.

 

[TerryH]

Terry,
Regarding your cyclone, which motor and blower did you use? I purchase a motor and an airfoil based on Bill's advice several years ago only to find out the airfoil couldn't handle the pressures in the system. So I'm back to square one. I won't be working on this for some time but thought I'd see what you used. I'm guessing a 5hp motor.

Funnily enough, most of my equipment matches yours (ie. tablesaw, jointer, planer, etc...).
Cheers.

I have the Leeson 5hp compressor motor. I personally never liked the air foils. I could not make the air foils work in my shop anyway. I have also deleted the air ramp from the cyclone body. I tested the ramps to death and back and could never see any improvement with them in the cyclone so mine is just an empty cylinder. I have a Cincinatti Fan 17.5" straight blade impeller in a housing that is a larger design than the normal fan housing.

A 15" radial impeller in the stock housing does a very nice job and is quieter than mine. As I stated before, mine is kinda overkill but I just had to give it a try.

 

[Angelfire]

Thanks. So you deleted the air ramp and just have the round duct secured in the middle of the cyclone feeding up into the blower?

 

[TerryH]

Thanks. So you deleted the air ramp and just have the round duct secured in the middle of the cyclone feeding up into the blower?

Yes. It's just held in place by the upper rings. Works great. All my testing showed that the cfm actaully dropped with the ramp installed.

 

[Gregger Rod & Custom]

Yes. It's just held in place by the upper rings. Works great. All my testing showed that the cfm actaully dropped with the ramp installed.

Terry, Thank you so much for sharing!!!!

Question on the ramp removal: you noted that you were able to increase CFM by removing the ramp, but does it let more of the very fine particles through the cyclone?

I know the filter will catch them, but I know myself well enough to know I will procrastinate cleaning / changing the filter, so I really want to remove as much as I can with the cyclone.

Thanks again,
Gregger

 

[TerryH]

I personally had a really hard time getting the ramp into the cylinder where it was really smooth so perhaps it's poor installation on my part. I could not tell any difference in the amount of cake in the filter or in the dust box with or without the ramp.

 

[Tim The Tool Man]

TTTMan, your inlet and outlet hose to your Thein appears to be similarly coated with fine dust. Is the Thein just for removing the large particulate or am I missing something?

I did have a bad joint that I fixed after that image was taken.

The Thein removes probably 95% of everything, large and small. I have never emptied the bags on my dust collector. I just slap them every now and then to knock any dust out of the pours in the bags. After maybe 6 years and about 30 barrel empties there is less than an inch of dust in the bag filter.

My collector is in a back room because it is loud and because no matter what, you will always get fine dust blow by. Cyclones are great but they will also get some blow by, less than my set up for sure but still some. They are also expensive, even a home made unit. I picked up my dust collector used for $50 and the Thein unit cost my under $50 in parts. Down the road I will probably buy or build a cyclone for the added efficacy, right now I only have a 1 1/2 hp motor on my unit. That said I can still cut, and shape something dust prone like MDF all day long and not have a huge mess in my shop.

Also, in my shop I have a ceiling mounted air filtration unit that I bought from my local woodworking store which works very nicely.

 

[Tim The Tool Man]

Here's the hood for the planer. Another HVAC register boot just cut and mated to the original planer hood. 6" plumbed right to this hood gets nearly every speck but be warned, this much air moving through the planer is very loud!!

I like your planer hood idea and will steal it! thank you very much!

When I was setting my shop up several years ago I read all through the Bill Pentz (sp?) website and I too second the importance of reading through it.

In my shop I have many of the same dust collection ducts at my tools as you have built for yours. I am interested in how well your miter saw set up works. I tried something like that but it didn't work well for me so I took a slightly different approach and have experienced near 0% blow by. Of course the volume/hp of my set up is wimpy compared to yours. I still have a collection hose at the tool's outlet port but I also built a hood that is also ported to my dust collector. Here is my miter set up:

 

[TerryH]

Tim......

That looks really good. I would have like to do something similar. Mine does pretty well but not as good as I would like. The issue for me is designing a hood system that will allow my sliding coumpound saw to articulate to all the positions. Boxes like you built would be optimum but they would have to be pretty big with the SCMS.

 

[Tim The Tool Man]

Tim......

That looks really good. I would have like to do something similar. Mine does pretty well but not as good as I would like. The issue for me is designing a hood system that will allow my sliding coumpound saw to articulate to all the positions. Boxes like you built would be optimum but they would have to be pretty big with the SCMS.

Ahh I see. I didn't pick up the fact that yours is a sliding compound miter saw. My slider is on a portable cart so I just wheel it outside and not worry about the dust. In the winter I rely on my table saw and radial arm saw for those types of cuts where a sliding compound miter saw is best.

 

[bob_mp]

Wow.

Great information here, thanks!

I have spent a lot of time on Bill Pentz's web site. It's fantastic. The part I was having a hard time reconciling was his suggestion to vent outdoors and the Wynn filters he sells with the kits. Are the filters good enough?

My heater has separated combustion (Modine Hot Dawg), so the negative pressure is not an issue.

As for venting outside, it should be fine from a rules perspective. I am open to putting a filter out there if needed. I need to deal with the noise issues for the phase converter and compressor in any case.

Are there any concerns, if venting outside, about cold air getting back into the shop through the dust collector vent?

Any thoughts on having a diverter to allow venting outside or inside?

Much obliged,
Bob