DC-Does anyone exhaust to the outside??

[John Keeton]

I posted a similar thread a couple weeks ago, but got no response. I want to install a DC system, but don't want to have a cyclone or filter system. I just want to exhaust to the outside. I need some thoughts from others. Thanks.

[James Suzda]

Along time ago I saw a plan whereas a woodworker made a "chip box" outside and just had a small 1 or 1 1/2 hp portable dust collector inside that would blow the chips and wood-dust into this box. The box was big enough that he would open it up and just dig the residue out. But, he did have a return air pipe with a filter on it to blow the air back into the shop.
(I just did a quick internet search and nothing came up) But, it was a pretty simple setup with just a big 4 x 8 x 4 wooden box outside with a pipe running inside the shop that had a small blower on the inside.

[Lee Schierer]

I've heard of people exhausting DC systems outside. In a warm climate this may be a good idea. In a cold climate you would exhaust all your heat outside in no time. A 1,000 cfm DC would empty a 20 x 20 x 10 shop in about four minutes. You will have to let air into the shop from somewhere outside to make up the difference and that air will be the outside temperature. Unless you get your heat for free or don't plan on using the DC a lot, I would rethink your plan.

[Keith Outten]

James,

You may have been thinking about me, I exhaust my workshop dust collection to the outside in a plywood box and I have the same setup at Christopher Newport University in our sign shop. At CNU I haven't had to empty the box yet, there are only about four inches of chips in the box after 12 months of use but we make small signs mostly and the chips are generally very small.

In my shop the chip volume is much heavier becaise I own a planner along with my CNC router, the planner produces ten times the chips as my router does. I don't use bags or any filters, the exhaust pipe from my DC goes right through the wall to the chip box and there is no return air. I know that the math would indicate that I should be losing a huge amount of heat but it doesn't work that way in reality.

Of course the weather here in Eastern Virginia isn't anything like upstate New York or the Dakota's with winter temps averaging in the forties during the day but even when we experience temperatures in the 20's I don't see much heat loss when I run my DC for long periods of time. My CNC router will run between 10 minutes to seven hours at a time depending on the job with the DC running the entire time so you can see that I run my DC more than most.

What I don't see is the really fine dust in the air, this is the result of an almost zero back pressure so my less expensive dust collector does the job of a larger machine. The dust that ends up outside is not in my shop where I would be breathing it all day. I don't have to be constantly emptying bags or have to wear a mask to dump them, nor worry about the bags filling up and my machine performance declining.

For many years when I was only working with wood I just blew the chips outside and didn't use a chipbox. Now I am using a lot of Corian which will never bio-degrade so I am back to using chip boxes in both shops. My home shop is located in a rural area but our sign shop at CNU is in a neighborhood at the edge of the University. The CNU chip box is located just a few feet from a walking path that hundreds of students use every day. They don't even realize it is there.

I expect it would be easy to design a return air pipe and filter the air return but I honestly don't see the need. It woud probably cost me more in filter media than I lose in shop heat.

John, I posted some pictures of the CNU setup here about a year ago.

[john frank]

I used to blow my planer shavings into a van type trailer while planing. The trailer sat outside and most days we would blow approximately 280 Cu Ft of shavings into the trailer. That was an 8" pipe removing air from the shop. It definitely lowered the temperature some, but I used wood for heat, so it wasn't that big of a concern. It stayed comfortable enough for a light jacket even in very cold weather. I did use a membrane made of a heavy felt over the back of the trailer so the air could escape without lots of dust in it.

[Bryan Wilson]

John
I'm down in E Texas and have had my exhuast going outside for years, but I do live out in the piney woods not intown.Now building cabinets almost exclusively i have a EZ-Router, PanelmasterIII, Woodmaster planer and 38" drum sander plus all the usual tools just a couple of times a year I use the tractor to spread the shavings, I have not noticed much change in heated air temp during the winter, but I use a remote clipped to my belt and only turn on the collector when it's needed.
good luck on what ever you decide.

Bryan W

[Duncan Potter]

When I was shopping for DC here in sunny Maine I was warned that exhausting outside would interfere with my oil furnace draft in my basement shop. I would assume the same would happen with wood or gas fired heat if everything is in one fairly airtight area.

[Ken Fitzgerald]

In areas where you have to heat a lot....ie..cold climates...it's my understanding you should have a return duct so that you don't pull a negative atmosphere in the shop....could pull carbonmonoxide / heat source exhaust gases back into the shop.

[Greg Funk]

I currently have my cyclone in a separate room from my shop with return air fed through a 2'x4' filter in the wall. I was thinking of changing the exhaust to outside but have pretty much decided against it based on recent measurements with the air quality monitor from Dylos. It seems the air in my shop is generally cleaner than the outside air so exhausting it outside and sucking in relatively dirty air doesn't seem to offer much of an advantage.

The only advantage I can see is the lower back pressure mentioned by Keith above. If your DC system is marginal you can gain potentially reduce static pressure losses by 1-2" by eliminating the filter.

Greg

[James Suzda]

James,

You may have been thinking about me, <snip>.

Wow, it's neat that the forum that I was talking about was right here on Sawmill Creek!!

I'll have to do a search on here to see if I can find the post again. What would be some good key words to search on. I tried "chip box" and got nothing.
Jim

[Steve Clardy]

My blower is outside also.
I do not notice a heat loss. I use wood heat.

[David Parker]

When I first heard about exhausting the DC outside, I thought it would be a neat idea. After further research, it's probably more bother than its worth for my climate. For one thing, I'd need to install an outside air return vent to avoid having a negative pressure inside the house (relative to outside). A negative pressure would adversely effect the DC performance and could potentially pull exhaust gases into the house from my gas hot water heater and gas furnace.

Since my inside air is usually either warmer or colder than the outside air, I would need to install a heat exchanger system as part of the air exhaust / return setup. Such an air heat exchanger can be found here (http://www.xetexinc.com/energy_recovery/products/hx_info.htm). Houses are being built so tightly now that it is sometimes recommended that a heat exchange system be installed to ensure adequate ventilation of indoor contaminants. Such a system could be made to work well with a DC, but it would cost something and take some time to design and build. I think I'll settle for a 1 micron bag or cannister exhausted inside for now.

Dave

[Keith Outten]

http://www.sawmillcreek.org/showthread.php?t=53504&highlight=chip

.

[John Keeton]

Thanks guys for all the input. My shop is in a separate insulated metal building. I presently have baseboard heat, but plan to put in a wood stove soon as I can find a good deal on one.

Like Bryan, I live in the country, so I can let the pile accumulate for a while before spreading it with a tractor. I like the sound of the remote.

Keith, Steve and Bryan, what kind of blowers do you guys use. The salesman for Oneida emailed me a suggestion for a 3hp, 1700 cfm, 8" inlet, but the price was $629, just for the blower. Seems a person ought to be able to do better than that??

Are yours wired 220v, and what kind of remote did you get Bryan?

[Steve Clardy]

Mine is a 4hp 3500 cfm blower I converted off of a 4-bag unit.
Did some modifications on it, and added a 13.5 cincinati fan.

[Rick Moyer]

I am currently without dust collection (except shop vac). I was waiting for a compilation of results from those with the Dylos device to determine how I will procede. I think I like this idea better, given the apparent inability to significantly reduce the dangerous dust without spending a small fortune (read: 3hp or bigger cyclone). I'm thinking I could get a <$400 DC unit, add piping etc. and exhaust outside; along with a reasonable air filtering device (I'm thinking squirrel cage blower with filter ala furnace blower) and I'd have potentially as-good-as in shop air quality as I would have going the super cyclone way. Seems to me that whenever you exhaust inside you need <1 micron filters and great air filtration or you are merely capturing the nusance dust. I understand the benefit of the cyclone for seperation, but I'm a limited use hobbyist and don't really see the ROI of the big cyclone systems. If I were a lot more active in the shop, ...maybe.

One question though is that many of the smaller DC units don't have the exhaust tube of the larger cyclones. They seem to have a large opening for a bag and/or often their exhaust port is lower to the floor; so how would I effectively feed to chips/dust to the outside? Could I convert a 14" bag opening to a smaller diameter pipe and would I be able to push chips up 6 feet to exit through the shop wall?

Some pics of the actual hardware of those who do this sure would be appreciated.

Edit: I should add that the shop is an enclosed former carport, but the sides are concrete up to about 4 feet. That's the reason for exhausting to the outside about 6 feet above the floor level. My ceiling is 87" so a big cyclone wouldn't work anyway.

[Matt Meiser]

After further research, it's probably more bother than its worth for my climate.

It works in my climate. I'm probably a good 15 miles from you though. :D

My shop isn't in the house though, probably isn't as tight as most houses, and I have a furnace that has a power vent which doesn't seem to allow the backdraft problem.

[John Browne]

Haven't yet but plan to. Seems a simple and foolproof solution to me. I live in the country and my shop is a detached garage with a MIL over. I'm going to put my 2HP Grizzly DC just on the other side of the back wall with a bit of a roof over it to keep the rain off. I'll replace the plastic lower bag I upgraded to with the original mesh nylon bag on the theory that it has lower resistance and will keep the flow high. Then I just check and empty the bag from time to time.

Or I may leave the lower plastic bag on and replace the upper filter bag with the original lower nylon bag. I don't want to filter the dust if it's outside, I want it to blow away.

As to sucking the heat out of the room, the heat comes from thermal mass, of which the air in a room has practically none. This is why when you turn on forced air heat in a cold room you feel warm quickly and then cold again as soon as the warm air quits blowing. There's enough gaps around my garage doors that I'm not too worried about losing oxygen.

[John Keeton]

Here is the suggested blower from Oneida. My shop is 24 x 24 and I have a tablesaw, bandsaw, planer, jointer, miter saw, and router table. The Oneida rep said the 3hp unit would do the job. It looks like a good unit, but seems pricey. I would like to find other options to consider if possible.

[Victor Stearns]

I am planing on locating my cyclone DC outside this summer. I plan on installing a diviter value so that I can return the air to the shop in the winter, or outside when warmer. I know there is a lot of talk that you can empty your shop of warm air in a matter of minutes. While I cannot say that this is my issue, I do think that the amount of time that I use the dc should not cause an issue. I also have radiant floor heat in the workshop and this not only heats the floor, but everything else in the shop. Kinda nice to have the extra heat sinks.
Victor

[Jim Heffner]

I posted a similar thread a couple weeks ago, but got no response. I want to install a DC system, but don't want to have a cyclone or filter system. I just want to exhaust to the outside. I need some thoughts from others. Thanks.

John, I have my homemade/shop built dust collector and chip collection
barrel outside of the shop. I piped it thru the wall and it is collected
outside where it needs to be, not inside, taking up the floor space and venting the exhaust air from the barrel back into the shop.
Jim Heffner

[michael osadchuk]

........ I apologize if someone has already mentioned this advantage of "venting outside": reducing the loss of air flow (CFM) from static pressure build up..... check out this thread from

http://www.airhand.com/designing.asp

these people estimate the static pressure deficit of a filter on duct collector to be two inches.... so for those of us with 1.5 to 2 hp dust collectors attempting to build dust collection system to deal with several hundred square feet of shop space and multiple machines (used one at a time), reducing the static pressure deficit by two inches is a significant gain

what I am considering is keeping a 2hp General dust collector inside my basement shop and venting the air that would otherwise be going into the 2micron fabric bag on top of the dc to the outside...... I'm thinking of removing the this top bag, plugging with a piece of plywood the part of the collector that the top fabric bag would otherwise rests, and drilling a hole in the center of that plywood plug for an 8" or 10" diameter metal vent to the outside..... perhaps adding to the collector, Phil Thien's innovative separator baffle above the plastic bag collecting the "big sawdust", to collect more of the fine dust before the exhaust is vented outside........

.... I've thought through the heat loss issue (don't think it significant vs. improved air quality gain) and have baseboard electric heating throughout the house so I don't have issues with carbon monoxide/combustion in the house.

see anything I may have overlooked?

thanks

michael

[Rick Moyer]

........ I apologize if someone has already mentioned this advantage of "venting outside": reducing the loss of air flow (CFM) from static pressure build up..... check out this thread from

http://www.airhand.com/designing.asp

these people estimate the static pressure deficit of a filter on duct collector to be two inches.... so for those of us with 1.5 to 2 hp dust collectors attempting to build dust collection system to deal with several hundred square feet of shop space and multiple machines (used one at a time), reducing the static pressure deficit by two inches is a significant gain

what I am considering is keeping a 2hp General dust collector inside my basement shop and venting the air that would otherwise be going into the 2micron fabric bag on top of the dc to the outside...... I'm thinking of removing the this top bag, plugging with a piece of plywood the part of the collector that the top fabric bag would otherwise rests, and drilling a hole in the center of that plywood plug for an 8" or 10" diameter metal vent to the outside..... perhaps adding to the collector, Phil Thien's innovative separator baffle above the plastic bag collecting the "big sawdust", to collect more of the fine dust before the exhaust is vented outside........

.... I've thought through the heat loss issue (don't think it significant vs. improved air quality gain) and have baseboard electric heating throughout the house so I don't have issues with carbon monoxide/combustion in the house.

see anything I may have overlooked?

thanks

michael

That's pretty much what I've been thinking I might do as well. I doubt I'll do much of anything before Fall, so please report back here if you do this with your results. I don't even have a collector yet, but your idea sounds good to me.