Seriously: Why not vent dust collectors outside?

You are not alone in venting to the outside. I was very surprised to see that The Wood Whisperer vented to the outside at his old shop. I’m not sure what he will be doing now that he has relocated. It appeared he had a little land around his house so it’s not like he would have been blasting his neighbors with the dust either.

I did learn a little something about Walnut dust a few weeks ago. Walnut trees create a chemical in their roots that prohibits growth in other trees. They do this so there is less competition for the sunlight in the canopy. The chemical remains in the wood and the resulting sawdust can actually kill trees if it is spread around the yard. Just something to keep in mind if you work in a lot of walnut or if your vent would blow material on other trees.

-- Behind the Bark is a lot of Heartwood----Charles, Centennial, CO

Hmmm.. what if one vented outside with an elbow facing downward into a trash can. Some of the dust would scatter but I’d think most of it would end up in the can. A cleaner shop, no dangerous dust and no back pressure from the open port. Hmmm.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful. http://web.me.com/deceiver6/Deceiver/Craftsman_on_the_lake/Craftsman_on_the_lake.html

Thanks for the reply. I wish I worked with a lot of walnut! I’m just a “for fun and function amature” and mostly use MDF/pine/plywood/poplar/maple. Also, I’m thinking that this ejection under my deck on plain old dirt won’t have much of an effect on the neighboring plants (all around 12 feet away).

I mean, most of the noise of the motor is still inside and it’s not too loud anyway. Second, only dust being blown onto dirt that I don’t want stuff to grow on…can’t be bad. Only problem is how to vent to the outside. I’ve got a poured concrete wall and a small basement window I can probably make a jig for. I can vent the basement when the DC is on.

not a bad idea Craftsman…why not do a little effort for a big reward…

Does anyone else vent outside? Seems like the ultimate answer to dust collection!

If you forget to open the window during heating season you will get a shop (house) full of CO. not sure I’d want to risk it. also here in Hew England (or anyplace else with cold winters) you would be venting a lot of expensive heated air out side

-- Fred, Springfield, Ma

I vent mine outside to a drum inside a dog house . Works great no problimo.

-- Jim from Heirloom Woodshop Southern Oregon

OK, so I’ve seen similar posts. I don’t heat or cool my shop. In the summer it’s cool in the winter it’s warm enough. Yeah, I’ll lose some heat or cool in the summer but does it ever add up to no fine dust in the workshop/house? I mean, pushing some A/C or heat out of my house isn’t much more than any other little woodshop expenditure. I’m really starting to form a strong opinion that we should vent dust outside.

Fredf provides one of the best points. The dust collector would create a negative air pressure in the shop and it would require a fresh air intake. If a large enough air intake is not provided, the negative air pressure will pull air back down the flue for the hot water tank and the furnace if they are gas fired. This will drag carbon monoxide into the living space.

If fresh air is provided to prevent this it is not a problem.

I have seen pro shops and hobbyists do this and there is always a layer of dust all over the area. It gets on everything and I was put off by it but they seemed fine with it. Before I saw this I had considered doing the same.

In all reality, given the safety consideration you could always try it and see how it works with your equipment.

-- Todd A. Clippinger, Montana, http://amcraftsman.com

If I vented my dust outside it would land in a mountain stream that is now protected by all the environmentalist so I would be..”up my creep without a paddle”. But, my neighbors ride their lawn mowers over with their trailers connected and we empty the bags into them so they can mix it with other stuffs and use it for mulch in their gardens. They want all the cypress we run for their flower beds so they take turns on a list we have. I’ve known them all my life so maybe that helps to keep their mouthy comments down when I’m making a lot of noise late into the night sometimes. Relief that the closest neighbor is about 75 yards away with plenty of trees between us and I think the youngest is about 78. Guess who they call when in need…especially when we have to use our generators…US! lol but we sure love all of them.

bruc

-- "Give The Gift of Life, Adopt A Child"

I vent mine out the back wall. My shop is on three acres of family land. And my back wall faces down a steep-sloping hill. I also dump a lot of my dust/chips/wood waste down the hill too. Its perfect for my situation but cant work for everyone. I live in coastal California so the heating/cooling is not a problem, and my shop is 100 yards away from the house.

Good discussion. Interesting note about walnut dust killing trees. I never thought of that.

-- Check out my new website! http://www.blakeweberwoodworking.com

I’ve been considering the same thing. I was going to vent under the wing shed but considered the dust layer. I was going to use a baffled box to slow the air and let dust settle before exiting. I know it wouldn’t catch it all but it’s mostly garden stuff and stored lumber anyway. Was talking to the wife while reading this, she suggested just letting it vent between the barns and letting it settle in the yard that may become horse lot anyway. I don’t have immediate neighbors to worry about, yea!!!!!!!!!
Another advantage I’ve been told, is when the bags and exhaust resistance is removed, the static pressure goes way up and dramatically increase collection ability.
There’s my rambling and two cents. I’m going to give it a try. BTKS

I’m going to be mounting the blower up near the ceiling on a concrete wall, run the exhaust a few feet with 6” pipe and out some sort of self-closing vent. The intake will be a straight shot down to the floor where my separator is with a three gang box nearby. This might take a week or two but I’ll post some results when I’m done. Not a huge loss if I don’t end up keeping the setup.

I just had an inspirational mindstorm. Run the dust collector outlet into the attic. Let the rafters fill up with shavings. Apply for an energy credit for adding insulation and doing it the ‘green’ way. Use the money to purchase a proper dust collector with a high capacity filter.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful. http://web.me.com/deceiver6/Deceiver/Craftsman_on_the_lake/Craftsman_on_the_lake.html

Wow, I thought everyone felt the long arm of the ‘Air Quality control Board’ as I do in Central California. Were I to be caught without adequate collection system in position, I would surely be shut down and fined.

It is my understanding the complete nation will soon be under similiar air quality standards.

I would be fearfull of building a layer of dust under a deck, as a small spark may turn into a major event, all-to-quickly.

Just my $.02

-- Rustfever, Central California

another thought about heating and cooling is you will in affect be sucking climate controlled air down the tubes so to speak

Several reasons.

#1. Typically home hobby workshops are smaller, enclosed spaces. Garages, Basements and the like… #2. In many cases, venting outdoors is not a realistic option. Do you want to explain to a potential buyer of your home why there is a 4, or 6” hole in the brick side of the garage? #3. Heating / cooling efficiencies. So you are going to suck all that air conditioned air and blow it outside? How good of an idea is that? #4. Environmental concerns. If the ultra fine particles are bad for you inside, they are still bad for you outside. You are merely moving an air quality problem. While we are not under California like oppressive regulations on air quality here in Texas, a responsible citizen takes care of what he has without being forced to… Because if they don’t they WILL eventually be forced to.

I will start another thread on a related subject. But to get y’all primed for the question…

What do you do with the dust you collect?

-- Trying to follow the example of the master.

Thanks for all the comments. I knew some would be polarized. Maybe I should have titled it, why shouldn’t I vent outside.

Even everyone’s hero Bill Pentz says a small hobby shop should just vent the fine stuff outside. I guess I should reiterate that I’m a “hobby” woodworker who does a project every now and then. I empty the separator occasionally and the dust bag every 6 months or more.

The vent will not be visible even if I told you were it was.

Basement air is not climate controlled and air intakes to the furnace are on the first floor. I crack a window and have very localized warming or cooling, but for a few minutes at a time…no big deal.

And I’m safe because I don’t live in Texas or CA… ;-) My firepit or lawn mower pollute the air more than my dust output will be. Mind you my nearest neighbor is 100 yards away and the rest are even farther.

What if you had a nice cyclone that barely puts any dust into the filter…then would some of you say putting it outside was good? Just a question.

And here’s an answer: the dust I collect goes in the trash.

My shop is a 10×12 shed, so there is no need to vent! I also run a Jet DC1100 dust collector.

-- CJIII Future cabinetmaker

Let’s say for example your vent is into a flower bed where it blows into a reasonably dense bush that gets watered relatively frequently… Your output air would have a reasonable chance of having the fines taken even further out of it… I can see doing something like that as quite reasonable…

Now to be the Devil’s advocate as it were. The blowers are designed to work with a certain amount of backpressure, or resistance to air flow. How would removing the backpressure impact the performance and longevity of the blower motor?

-- Trying to follow the example of the master.

Are the blowers designed to work with a certain amount of backpressure? In my head (ie. might be totally wrong), an internal combustion engine relies on backpressure for torque and horsepower but an electric motor spinning at a predetermined RPM should last longer with less of a load on it. I’ve read of people venting outside and having scrubbing issues in separators because of the CFM increase. I could be totally wrong.

How much air leaves the house on a Saturday when 5-6 loads of clothes go thru the dryer?

At my house that could be several hours of exhaust leaving. Not saying it is the same of course, just pondering this issue.

-- If everyone is thinking alike, then no one is thinking.

I think that the amount of air that leaves the dryer is insignificant considering the amount of heat that the dryer produces and then vents outside.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful. http://web.me.com/deceiver6/Deceiver/Craftsman_on_the_lake/Craftsman_on_the_lake.html

The blower motors shouldn’t care about less load. They need to be sized to provide sufficient CFM to move the chips and dust then force the exhaust through the desired size of filtration system. I can’t imagine any of these systmes being affected by the lack of back pressure. If you are removing chips from 20,000 square feet of manufacturing facility, that could be another matter:-))

-- Debt is nothing more than the 21st Century's form of slavery.

OK Blake, I spent about 45 minutes looking at your shop pictures, expecially that dewalt RAS, so my envy meter is pretty high about now. And you have the nerve to say temperature is not a problem year round in your shop. I live in Houston where you just don’t go outside in the summer. A place where your paste wax will melt to a fine liquid, right in the can, the first day of June.

Shame on you to JasonWagner. Cool in summer. gee thanks ;>)

-- david roberts, houston area, "A little knowledge is a dangerous thing, but that has never been a problem for me."

Jason, there is a good discussion about load on the motor when venting outside on Sawmill Creek. Specifically the posts by Rick. Here is his basic summary:

..snip..
Unrestricted exhaust is not going to increase motor load.

The reverse is true at the outlet. When you remove restriction at the outlet, the pressure differential between the inlet to the outlet is reduced and the motor doesn’t need to work as hard. When you obstruct the outlet, the pressure differential is greater, and the motor needs to work harder.
..snip..

http://www.sawmillcreek.org/showthread.php?p=1089161#poststop

-- Jon

OK, so throwing my input into the ring:

Venting
On the issue of venting outdoors, numerous species of wood cause many adverse reactions in people, from simply irritating to full blown allergic. I know I am personally a little sensitive to walnut dust, but that doesn’t stop me from using plenty of it. But would outdoor venting of the fine particulate matter be a potential irritant for your neighbors? You are talking about venting the fine dust outside, which is exactly the material which can and will be blown around by even a mild breeze. By an air cleaner and eliminate the potential for problems. In ou rlitigous society, who knows what kind of headache you are asking for.

Disposal
I sell my dust/chips to a local farm for $1/per contractor bag full, which they in turn use for animal bedding. on a good week, my shop produces 20-25 bags per week. and on heavy planing orders, i have ammased that many in just a few hours. Selling it to the farm beats hauling it to the dump or paying a dumpster fee. *One VERY important note on this – Walnut is very detrimental to animal’s hooves. So if you go the route I have, make sure you don’t contaminate your dust collectings with any walnut or the really really exotic stuff. Cherry, maple, oak, poplar, pine, ash, beech, birch, etc are safe. basically any of the standard fair of domestics, and even most similar imports are ok.

I have a 10X12 shed/shop. It backs up to the woods. I blow everything into the woods. I mounted the motor to the wall upside down and drilled a 4” hole in the back wall of my shop. Works like a charm.

-- Rick

That’s KOOL, return it right back to where it came from :-))

-- Debt is nothing more than the 21st Century's form of slavery.

I recently purchased a 7 inch “Y” connector to hook up to my dust collector outlet. I have a 1400 cfm Oneida cyclone system…Both legs of the “Y” have a blast gate and one leg will go to the filter and one leg vented to the outside of my shop. This offers the Best of both worlds since I can vent outside when the weather is nice and my doors and windows are open and I can vent it into the filter when I run the A/C or heater.

-- Each and Every step of any project should be considered your masterpiece if you want the finished product to reflect the quality of your work. Greg Little

Greg, I like your solution. BTKS

I’ll post some pictures soon, but I mounted the motor and blower housing of my Jet DC1100 to my basement (solid concrete pour) wall. (side note: man was that thing hard to hold up on the wall while on a short ladder, I’m still paying for that!) Then I put my chip separator under it and also added the famous Thein separator baffle. I have a Jet separator lid and a 37 gallon tub below it. I didn’t vent it outside yet, but couldn’t wait to try the setup out. I have recently added a three gang blast gate box I made from ShopNotes magazine. I turned it all on and threw fine dust from my shopvac into the system and saw nothing come out the exhaust that I will be venting outside. The separator works great as far as I can tell on a small sample. With my small shop usage I don’t think I’ll be able to tell I’m venting outside except for the fact that I won’t be introducing fine dust into my shop.

Great follow-up. I hope to hear about the real world trials. BTKS

Great idea.

-- --<<<<<< I will not stop until I get it right. >>>>>>--

Jason,

Be aware that the fan that I use when spraying puts my basement shop under enough negative pressure to backdraft the furnace if I don’t provide a good source of makeup air. Said fan is far less powerful than the DC-1100 I used to own.

Make sure you open the basement door and possibly an upstairs window if you’ve got a furnace and/or gas or oil burning water heater in the same basement with your shop.

-- - Please help keep Lumberjocks an enjoyable escape by refusing to participate in political discussions. Simply spit out the bait and ignore the thread...

Termite has the right idea. The thought of shooting my bought and paid for, or worked for hot shop air into the atmosphere in January leaves me cold!

The idea of a split discharge is neat, especially if your January’s range to -25 Farenheit like mine do.

-- John

just a thought, I don’t know if it would be a problem or not, but what about TERMITES, if the sawdust is on the ground, would it draw termites? if so, it would not be good to have a pile of sawdust too close to the house.
just asking, maybe an exterminator out there would have an answer.

-- Smitty!!!

Termite’s setup is ideal. I would recommend one use a high quality filter when heating the shop and using the collector with the filter connected. Here is a link to some very high quality filters. I like to use 2 of the 9L300BL filters connected together. Two of these filters connected together will give one the proper air return necessary for the dust system to function properly without major reduction in CFM draw at the machine. One filter puts does not allow enough air to pass through for efficient flow.

-- Oldworld, Fair Oaks, Ca

So far on my scale of woodworking I’ve seen no dust make it outside. I have the blower mounted on the wall, the chip separator below it with a Thein baffle built in, then off to the tools. I don’t have a way to measure the air flow but I do know that the separator causes a decent amount of static loss. It is doing OK for what I want at the moment. I agree that this isn’t for everyone. If you run your dust collector for extended periods of time this isn’t for you. I turn mine on with the remote, make the cut and turn it off. I have a window that I can pop open and closed easily. When it’s nice out it’ll just stay open, when it’s not I’ll go through the pain of opening it and closing it. I didn’t however spend any money for my adjusted setup. In the future if I out grow this it will only be a matter of patching a hole in a soffit under my deck that no one can see. Thanks for everyone’s opinions, concerns and ideas. It made me think about a few things.

Great discussion guys! I have my Jet DC1100 in my garage which is next to my basement shop. I leave a garage window ajar and this keeps the noise and fine dust out of my shop. After reading above I plan to install a Y to the outside. I might even bury a drain pipe under the back yard into the woods where I dump my chips anyway.

I have not noticed a change in the house temp in summer or winter when running the collector for hours straight. Also, I never have downdrafts from the chimney (we heat with wood). Here is why. The volume of my house is about 60,000 cubic feet, so it takes an hour for the collector to change the air in the house. When we built our house we were told it would have a complete air change every 1-2 hours. Houses tighter than this need an air heat exchanger to keep from building up toxic dust and fumes. The furnace/air conditioner has to heat this air in addition to heat that goes through the walls and windows and to overcome solar heating in the summer. So the dust collector is a relatively small load on the HVAC system. And our house, a typical one, has plenty of leaks to stop downdrafts.

-- David, West Lafayette, http://REDIpix.com

llamadave,

How many square feet is your house? 60,000 cu/ft = ~7500 with 8 foot and ~6000 with 10 foot ceilings… Nice! <g>

I think you’re getting plenty of makeup air via your HVAC system.

Downdrafts with my spray exhaust fan have occurred in breezy, but not windy, winter conditions. My fan and oil burning, domestic hot water producing, furnace are collocated in a windowless 900 sq/ft basement. The A/C doesn’t appear at all in the basement. The house is built to typical 1990’s New England insulation and ventilation standards for hot water heat (no heating air ducts). The downdraft evidence is enough smoke to set off basement smoke detectors.

It’s all 100% repeatable for me, and easily avoidable by opening the door to the upstairs. If a shop or house has air ducts, it’s probably not a problem, but with hydronic or steam heat…

-- - Please help keep Lumberjocks an enjoyable escape by refusing to participate in political discussions. Simply spit out the bait and ignore the thread...

Well, that was a quick calculation assuming a rectangular solid. A more accurate number is 40,000 cu ft. This includes three floors and a full basement, all having air ducts, and ceilings 10,9,8,8 ft. My wife told me since I posted above that she has smelled downdrafts from the masonry wood heater (I am in the shop when the fan is on!) but this is not a regular thing. We do have several CO detectors and they have never registered anything. I will probably have more of a problem when I vent outside.

-- David, West Lafayette, http://REDIpix.com