Box enclosure with exterior exhaust for HF Dust Collector

Hi Andrew. I have no idea for you…just wanted to say welcome to the site. Hang around, you’ll get answers

-- Gary, DeKalb Texas only 4 miles from the mill

If I understand your plan, you want to box the upper (filter) bag and vent it thru a window to the outside. If that’s right, what will drive the air from your box into the 6” flex and thru the window? Without some kind of driving force, you’ll just build up a bunch of dust in your box.

Also, that 6” flex will actually reduce the air flow thru your system (backpressure).

-- Adversity doesn't build character...................it reveals it.

Sawkerf, I think the same air pressure that’s forcing the air through the bag’s 20 micron pores will push the air through the 6” flex and out the window. Remember, CFM in = CFM out (as long as its sealed).

Andrew, I think your plan will work.
Alternatively, I would suggest building something like the Thien separator and directly venting the exhaust outside without the bag. There is a design out there that incorporates the Thien baffle directly onto the ring that your bag attaches to. From there you simply need a donut shaped plywood cover to seal the top of the ring (w/o the bag) and adapt it to your 6” flex that goes out the window. Only the very fine (flour like) particles seems to escape a properly built thien separator so I don’t think you’ll have any problems shooting those out the window.

Sending it over to the neighbors is always a good way to start a conversation….......

-- mike...............

Andrew, not sure if this application would work in your case but yes these CD’s move a lot of air from what you are saying you are not ACed? I have a stand alone shop and added an outer storage for my DC and also air compressor as my shop is ACed so I added insulation to the outer storage. I have a 24” window that separates the shop from the shed and added an AC filter over the window to keep dust out and cool air back in.

Here are pictures of my setup.

-- Randy - If I'm not on LJ's then I'm making Saw Dust. Please feel free to visit my store location at http://www.facebook.com/randy.blackstock.custom.wood.designs

I have the HF 2 hp DC. I decided to get rid of everything, except for the motor and fan and direct the exhaust to the outdoors. I put a 55 gal drum between the DC and the pickups. so that large chunks and heavy sawdust goes and settles in the drum and only the light dust passes throught the DC.

Andrew I’ve been thinking about this for a long time now and once I buy my own house with my own workshop I’m planning on doing something similar to Blackie, but more of a lean to version. The plan is for it to be air tight with the only air outlet through a flat removable filter element (room filter style). After that maybe a baffle that can be opened or closed to choose if air is vented back into the shop of outside.
I think it would be fairly easy to build something like this inside of the shop too, space permitting.

-- Blinded by brilliance

Sarit -

The pressure will definitely cause flow thru the 6” duct, but only enough to stabilize the pressure. Most of the dust will stay in the box since the flow in all parts of the box won’t be great enough to carry it to the duct.

To get all of the dust out the duct, the air flow must be toward the duct and have enough velocity to carry all of the dust with it.

-- Adversity doesn't build character...................it reveals it.

I took a slightly different approach, I built my “box” on the outside of my stand alone shop. The noise and dust (although a small amount of dust) are outside. My 1 1/2 horse collector is wired through a heavy duty (high amp) switch so it is easly turned on or off from inside. It does suck heat from the building, but I heat with wood so I throw another log in the wood stove. I used drier vent ducting and flex hose and flex hose fittings (Ys, blast gates, and so-on) to make a permanent conection to each machine. Just inside from my dust collector is a 2 stage separator (inside for easy emptying). I chose 4” ducting for my set up, and have had very few problems.

-- John of Idaho

Thanks for the great ideas everyone.

I did a preliminary experiment making a Thien separator. W/o the separator or the filter bag, a huge tornado of dust shoots out the top. Adding the separator, but still with no filter, almost nothing visible comes out. So Sarit’s suggestion looks viable. Note this is only testing with materials already in the bag, and does not account for an inflow of dust and debris from the tools.

BTW, I got to use my new table saw while making the standoffs for the separator. What a dream! (SawStop PCS 3hp—totally overkill for this little task).

-- Andrew, Santa Cruz, CA

I have the PCS also. Its a great machine. I also live close to the SF bay area not too far from Santa Cruz. There’s seems to be some saw mills in your area so you might be able to score some cheap wood. I think I found them in Craigslist.