# dust collector exhaust



## retire2$ (Feb 25, 2014)

I have a 1 HP dust collector. It has a 4 inch inlet and a bag filter. 

My plan is to exhaust the air outside. The dust collector currently has a 5 micron bag for dust collection. What are your suggestions for covering over this large opening and what would you use for the exhaust? My thoughts would be a piece of plywood secured to the opening and then running 1 or 2 of the 4 inch lines outside since I have extra 4 inch flexible lines. If the recommendation is two lines I would need to come out with a 6 inch wye reduced to 4 inch. Also, I plan on using a home made cyclone in front of the dust collector. Should the cyclone be placed near the dust collector or closer to the tool. My only tools are a 12 inch miter saw, 10 inch table saw and maybe a home made down draft table for a scroll saw. 

I do not plan on using more than one tool at a time. I am mainly interested in keeping my lungs and garage clean.

Thank you in advance for any advice and suggestions you are willing to share.


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## jw2170 (Jan 24, 2008)

Welcome to the forum.

Thank you for joining us, Jim.




Just a reminder that you do not need 10 posts to upload your photos to the forums. Click the go advanced button and you will find a button that says manage attachments. Select this and you will be able to upload your photos.


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## Big Steve (Feb 12, 2012)

Jim, if using a cyclone in front of the DC, why do you want to exhaust outside? 

On my shop vac with a Dust Deputy, for example, there is NO noticeable dust that gets as far even as the vac, much less back into the air.
The noise would still be inside
If you get the outlet wrong you will effect the efficiency of the blower
The make-up air back into the shop will be unheated or uncooled.

Just my thoughts.


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## papawd (Jan 5, 2011)

On my miter saw built into a work table along the wall with a drop to make the miter table even with work table also built a cover with 2 sides and the back wall helps contain the dust missed by dust collector pick hose hooked to back of miter saw.. As for table saw dust collection is harder due to no way to contain what is not sucked up by D/C. but not a real problem the down draft table should be fine.... My dust deputy is hooked right in front of a shop vac for most small tools and pinpoint dust control on the shop vac I HIGHLY suggest a Hepa filter to really clean the discharged air ....I would put the cyclone right ahead of the D/C this would help ....GoodLuck


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## routergieck (Feb 11, 2013)

I just used a dryer exhaust vent hood. My dust collector is in a small garden type shed just outside of the shop to eliminate noise and is turned on and off with a remote type switch that I can carry in my pocket. Just have to open or close the appropriate blast gates for each tool as I only run one tool at a time also. I thought makeup air would be a problem so I installed two 4 inch inlet vents (vents on inside of shop with non louvered vent hoods on the outside) but the inside louvers hardly open when I have the dust collector on. Seems there is enough space around 16 ft garage door molding to let make up air in. Heating has not been a problem. You can get almost any size of exhaust vents.


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## Gene Howe (Jul 10, 2007)

Not knowing how your particular DC is configured, my suggestions might be off a bit.
I removed both bags from the DC and mounted the impeller unit to a piece of plywood so that it would sit upright. Then cut a hole in the wall to accept a 4" piece of chimney flue. Connected the impeller exhaust port to the flue with a short piece of flexible hose. 
The chip collector is just a 35 gal. trashcan with a plastic wanna be cyclone lid. It's placed close to the impeller so that the hoses to the machine(s) are all that has to be moved when switching from machine to machine.
My shop is heated and air conditioned. I've not noticed any difference in the temperature when using the DC. But, it only runs intermittently and probably no more than 2 hours a day.


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## retire2$ (Feb 25, 2014)

Jim, Thanks for the welcome. I do not have any pictures to load and if I did I don't have enough computer savvy to upload them.

Steve, I only do small projects inside the garage and not really much of a wood worker in terms of building intricate things such as furniture, etc. The reason for venting outside is that the dust collection bag is 5 micron and since I do not currently have a cyclone I get a lot of dust when I use the table saw or miter saw. I am not concerned about the heat loss and I do not have air conditioning (so no worry about cooling loss). Therefore, I figured if I vented to the outside I would not have to worry about dust even if some got past the soon to be built cyclone.


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## DaninVan (Jan 1, 2012)

Hi, Jim; welcome!
The perfect scenario would be for the DC to exhaust through a very large opening into a vacuum (no, not a vacuum cleaner; a real vacuum). The theoretical purpose being the difference in pressure between the inlet and the outlet. The less restriction on the outlet side, the more effective/efficient the impeller will be.
Whatever diameter the existing outlet collar on the machine is, that would be the optimal vent size. Anything less will begin restricting the air outflow..._but without a bag, definitely more efficiently_. It's going to be messy on the outside, however.
Why not just buy a new 1 micron bag(s)?


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## Gene Howe (Jul 10, 2007)

Dan,
With my wannabe cyclone ahead of the impeller, I get zero to minuscule amounts of dust outside. Mine's a 2 hp unit. Don't know if that makes a difference, though. You are absolutely correct about the increased efficiency by venting outside, too.


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## Semipro (Mar 22, 2013)

Hello Jim, really pleased to see you join the community, welcome to Router Forums!


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## Mike (Nov 22, 2004)

I think Dan's suggestion on a new bag is a good choice.


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## old55 (Aug 11, 2013)

Welcome to the forum Jim.


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## retire2$ (Feb 25, 2014)

Thanks for the replies. 

Venting the exhaust outside would eliminate my need to buy another bag and the air in the garage will be cleaner. Should I build a box over the exhaust to act as a manifold and then run the exhaust to the outside? Should it just be one 4 inch line since that is what will be connected to the tool and cyclone or should I add more 4 inch lines to equal the square inch area of the exhaust opening?

Thanks for your input.


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## tvman44 (Jun 25, 2013)

I just used some 4" DC flex hose to go through a panel I fitted in the window. Works great.


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## MAFoElffen (Jun 8, 2012)

grandfatherto11 said:


> I have a 1 HP dust collector. It has a 4 inch inlet and a bag filter. The dust collector currently has a 5 micron bag for dust collection.... I am mainly interested in keeping my lungs and garage clean...


As mentioned by others, the biggest piece missing that is going to help is a cyclone separator added between your tools and the DC unit. I'm a big plus one on that.

From there, you have so many options, it's mind boggling.

Easiest would be to keep your setup how it is and replace the 5 micron bag with a 1 micron bag or a Win cartridge filter.

Next would be as other's said about taking the impeller off the unit, using the cyclone in your separator (again noted as being between the tools and your impeller), then venting the exhaust from your impeller outside.

Of course _all_ the piping could go directly outside to an exterior located separator... like a lot of commercial units are. That way it saves space in your shop and is quieter. But then the challenge is to plumb it and keep it safe from the weather and from prying hands.


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## Marco (Feb 21, 2009)

I have mine blowing straight outside through a dryer vent


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## retire2$ (Feb 25, 2014)

It has been awhile since I was on this forum. I still would like to exhaust the air from the dust collector to the outside. I still would like to know what would need to be done to accomplish this. If I remove the filter bag what would I put over the opening that originally held the bag to vent the air out? The dust collector would be inside and the exhaust line would be vented outside. MAFoElffen made a suggestion about taking the impeller unit off. Can someone give me details on how this would be done. I still am having a hard time visualizing how and what to cover over the opening where the top bag would be removed.


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## al m (Dec 13, 2012)

You would eliminate that piece completely,instead of the blower blowing into that it would go straight outside
Not a fan of that myself but it will work,I personally can not afford to remove so much heated air from my shop


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## Nickp (Dec 4, 2012)

Jim...maybe this might spark ideas...lots of pictures and videos too... 

Modified Harbor Freight Dust Collector | Jays Custom Creations

Good luck...welcome...Nick


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## DaninVan (Jan 1, 2012)

Jim; back to my original comments.
The exhaust vent is not 4"...it's the size of the impeller's exhaust diameter as an absolute minimum. 9" maybe? its the size of your bag's opening, not the _ inlet_ diameter. The bigger the unrestricted opening the better!
In a perfect world there' wouldn't be any bags.
American Fabric Filter - Baghouse Bags


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## tvman44 (Jun 25, 2013)

I exhaust my 1hp DC outside using 4" flex line connected to a piece of 1/2" plywood that fills the gap under the window. I have a Thien style separator ahead of the DC and don't see anything coming out the exhaust, this setup is connected to my scroll saw. I plan to vent my 2Hp DC the same way only using 5" flex line through the window in the same manor for all my larger tools.


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## retire2$ (Feb 25, 2014)

NickP. Thank you. After seeing the video it makes a lot more sense to me. As the old saying goes "A picture (in this case a video) is worth a thousand words".


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## Nickp (Dec 4, 2012)

grandfatherto11 said:


> NickP. Thank you. After seeing the video it makes a lot more sense to me. As the old saying goes "A picture (in this case a video) is worth a thousand words".


You're welcome - "enjoy the toy".


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