Question about non-circulating dust collector system

[Matthew Bennett DC]

Hello friends,

Now... before you say anything, I know I told you guys that I made a promise to my girlfriend that I will not start on new projects until my patio is done. With this said, I am not breaking it because I am simply talking with fellow woodworkers and planning things out in my head. Nothing wrong with that as long as I continue to work on the patio. Is my logic sound? :confused:

Anyway back to woodworking ;-) my next step is to obtain a dust collection system and been browsing thru internet and realized something. I do not need one that re-circulate the air back in the shop because the air will be vented to the outside. So, I do not need one with fancy filtration system or anything like that so I will be able to save a bundle on the system.

Does that exist? a dust collector that simply dump sawdust, etc into a barrel and vent the air to the outside.

[glenn bradley]

Being able to vent outside would be a dream come true for me. there are variations on this method:
1. you live in the country and can vent the whole kit and caboodle right out into the yard . . . heaven.
2. you can get away with venting your fines out into the yard but, have to separate your larger spoil for some other form of disposal.

It sounds like you are after option 2. This would just be a cyclone where you remove the filter and plumb the exit port to the outdoors.

[Matthew Bennett DC]

Being able to vent outside would be a dream come true for me. there are variations on this method:
1. you live in the country and can vent the whole kit and caboodle right out into the yard . . . heaven.
2. you can get away with venting your fines out into the yard but, have to separate your larger spoil for some other form of disposal.

It sounds like you are after option 2. This would just be a cyclone where you remove the filter and plumb the exit port to the outdoors.

Bingo, #2 is exactly what I am looking for. A barrel for heavy stuff and fine particles would be vented to the outdoor. However, I would like to avoid buying one that is designed for re-circulation as it would have a filtration system (higher cost). I prefer to get one that doesn't have a filtration system for re-circulation to save money.

[Carl Kona]

Matthew,

If I understand what you are looking for is a blower that will suck the dust from your shop and blow it into a barrel outside? Unfortunately very little will land in the barrel as you will be blowing 700-100 cubic feet per minute of air and dust. Most will splash out by the force going in. What Glenn suggests is what most do when venting outside. Collect most of the big stuff with a separator and the fine bypass will go outside (no collection).

You still want a 2 stage DC but without filters.

[Jim Becker]

I agree with Carl that for practical reasons, pre-separation is desirable. The separation "can" happen after the blower, but then you have to be careful about what gets picked up...metal, such as a screw, passing through the blower presents some level of danger of sparking.

The other "elephant in the room, err...shop" is that venting to the outside also vents your heat and AC if that's applicable. ;)

[Art Mann]

Here is a little math for your consideration. You didn't say how big your shop is but lets suppose it is 24 X 36 X 9 feet. That is 7,776 cubic feet. Lets also suppose your collection system will maintain a modest 600 cfm. That means that the entire volume of air in you shop will be replaced every 13 minutes or so. The replacement air will unavoidably come from the outside. What I am saying is that you need to run the collector as little as possible. If it is run continuously for any length of time, your shop temperature will drop quickly if it is cold outside.

[Matthew Bennett DC]

Holey moley, I had absolutely no idea that a "modest 600 cfm" would replace my entire workshop in approx 13 minutes. My workshop is in my basement and the total Sq is 900.

At first, I thought I would just keep the door to my basement open but that would end up stealing all heat from the whole house pretty quick. That wouldn't be pleasant for my gf to deal with.

I think I am ok with recirculating when dealing with extreme temperature (winter or summer) and that would only be what? 5 months total annually (DC/MD)


... entire volume of air in you shop will be replaced every 13 minutes or so. The replacement air will unavoidably come from the outside. What I am saying is that you need to run the collector as little as possible. If it is run continuously for any length of time, your shop temperature will drop quickly if it is cold outside.

[Julie Moriarty]

I've been venting my DC outside for decades. My DC is a Delta drum-type that came with a bag. That bag didn't last long and I quickly ran a duct outside with a dryer-type vent hood. Problem was not much of the waste ended up in the drum and ended up on the lawn outside. For years I raked it up or just mowed over it until I converted the drum setup to a cyclone. After that, pretty much all the waste that ejected outside was fine dust.

In my last house, makeup air wasn't a problem, at least not a noticeable one. Who could notice the pulling of air in from every crack and crevice throughout 4000 sq ft? Not the DC is in the garage so I open a window or door when I run the DC.

[Deb Clarkson]

You wouldn't have to be replacing all the air in your shop every 13 minutes if you could set up a duct to bring in replacement air in a location central to most of your machines. Instead you'd just be replacing the air in a smaller area and the heated air in the rest of the shop could be mostly undisturbed. This would work best if your shop heating is radiant rather than forced air. You'd probably still feel a pretty strong chill if your're standing between the tool being sucked from and the duct bringing in the replacement air. You would also need a convenient way to seal off the duct when not running the dc.

[Art Mann]

It isn't going to be possible to prevent outside replacement air and inside air from mixing.

[Matthew Bennett DC]

Happy new year to all of you.

I think I will just open a few basement windows on one end with fans drawing air inside, and open the basement door on the other side with a fan blowing air outside. Naturally, I'll be wearing a face respirator with P100 filters.

That will give my lungs 100% protection until I am ready to install an actual DC system.

EDIT:

Actually, I wont be opening any windows for a while due to the arctic temps. In fact, the main water pipe servicing my area burst today right front of my house! Fortunately, the burst pipe was in the street, not on my property so I do not have to deal with the repair or financial hit.