Results 1 to 13 of 13

Thread: Make up air for small dust collection system.

  1. #1
    Join Date
    Jun 2008
    Location
    Lubbock Texas
    Posts
    931

    Make up air for small dust collection system.

    I have a small 13'x23' shop where I make small crafty items that require a lot of sanding. I have a small sanding station with a 4" connection to my 2HP dust collector that is in a different building. I upgraded the 4" to 6" to match my 6" main duct. and saw a good improvement to my dust collection at this location.
    Now that it is over 100° outside my air conditioners are working to keep me comfortable in my shop. Exhausting all this air warms up my shop because the air is leaking into the shop at the doors and windows.
    Today I installed a 6" make up air duct that comes from outside my shop to this sanding station. Now when I run the dust collector for this operation the air exhausted by is is made up by the new make-up air duct. Sawdust is drawn away just fine but this system is not warming my shop up as much now because there is less inward leakage around my doors and windows. It worked well, so I put in a second 6" make-up air duct at my stationary belt sander. I have blast gates on all these ducts so I can control the airflow as needed.
    I penetrated my outside wall with the 6" metal duct and I made two 6" "dryer vents" from sheet metal that are mounted on the outside of my shop. (I am a retired sheet metal worker so this was simple for me)
    No PHD, but I have a DD 214

  2. #2
    Join Date
    Dec 2006
    Location
    Porter,TX
    Posts
    1,520
    Jim that is one neat ideal,thanks for posting

  3. #3
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    9,879
    A proper vent over a stove uses coaxial ductwork for the same reasons.
    Bill D.

  4. #4
    Join Date
    Apr 2010
    Location
    Houston, Texas area
    Posts
    1,308
    I can't visualize why pulling makeup air from outdoors through your doors and windows is any different than pulling it through 6" vents, in terms of shop temp control. If you are bringing in outside air, you are bringing in outside air.

    Maybe with your old system it was actually pulling hot air from the attic, through an attic stairway perhaps??? That could make a significant difference.
    Mark McFarlane

  5. #5
    Join Date
    Jun 2008
    Location
    Lubbock Texas
    Posts
    931
    What is happening is, the air is exhausted at one point and 13" away the outside are is coming in to replace the exhausted air. It is a short circuit of air. So 90% of the air exhausted has been only in the building for about a second and back out along with the sawdust. We did this often in the HVAC business especially at commercial kitchen hoods.
    No PHD, but I have a DD 214

  6. #6
    Join Date
    Apr 2010
    Location
    Houston, Texas area
    Posts
    1,308
    Quote Originally Posted by Jim Finn View Post
    What is happening is, the air is exhausted at one point and 13" away the outside are is coming in to replace the exhausted air. It is a short circuit of air. So 90% of the air exhausted has been only in the building for about a second and back out along with the sawdust. We did this often in the HVAC business especially at commercial kitchen hoods.
    Thanks Jim. If I understand correctly, with your new, improved vented method the make up vents are 13" away from the exhaust port, so you are getting some conditioned air returned. Is that correct?
    Mark McFarlane

  7. #7
    Join Date
    Jun 2008
    Location
    Lubbock Texas
    Posts
    931
    No, the conditioned air is kept out of this circuit (for the most part) Outside air is passing across the sanding area and is then exhausted to the dust collection system taking the saw dust with it. This avoids exhausting conditioned air in my shop.
    No PHD, but I have a DD 214

  8. #8
    Join Date
    Apr 2010
    Location
    Houston, Texas area
    Posts
    1,308
    Quote Originally Posted by Jim Finn View Post
    No, the conditioned air is kept out of this circuit (for the most part) Outside air is passing across the sanding area and is then exhausted to the dust collection system taking the saw dust with it. This avoids exhausting conditioned air in my shop.
    I understand now Jim. Great idea. Thanks for the explanation.

    This approach might work for venting a temporary spray booth in my shop: Intake from a window with a baffle and some flex duct > rout duct into the temporary booth area > exhaust fan onto the driveway. Better than just opening the windows in terms of loss of conditioned air.

    It was 92 today and I relocated a couple of palettes of left over brick using a garden wagon and about 4 loads of sand. I am looked forward to getting my new air conditioned shop ready to move in. We should have the AC going in 2-3 weeks.
    Mark McFarlane

  9. #9
    sounds cool, maybe some pics? or maybe you are pic challenged like me?

  10. #10
    Join Date
    Sep 2006
    Location
    Deep South
    Posts
    3,970
    It took me a while to get it too.

  11. #11
    Wow, what a great idea! This week has been super hot and humid here too. Condensation started forming on the duct pipes in the ceiling and then dripping on my stuff. My panic solution was to put plastic over stuff under them. I have 5 blast gates that are spaced several feet apart. Im wondering if there would be a way to make a traveling make-up air duct that could be moved easily from port to port or if it would be easier to run seperate ones? Also i wonder if using an active make-up as opposed to passive would be beneficial or if it would mess with the exhaust flow?

  12. #12
    Join Date
    Jun 2008
    Location
    Lubbock Texas
    Posts
    931
    Quote Originally Posted by Evan Stewart View Post
    Wow, what a great idea! This week has been super hot and humid here too. Condensation started forming on the duct pipes in the ceiling and then dripping on my stuff. My panic solution was to put plastic over stuff under them. I have 5 blast gates that are spaced several feet apart. Im wondering if there would be a way to make a traveling make-up air duct that could be moved easily from port to port or if it would be easier to run seperate ones? Also i wonder if using an active make-up as opposed to passive would be beneficial or if it would mess with the exhaust flow?
    Active make up air is what we used in industrial HVAC work but it is overkill for our needs (In my opinion) I used the cheap 6" wireflex from Lowes for the make-up air and it works fine. I am sure a movable make-up air using this flex duct would work well. This duct comes in 25' long sections and can be cut to length easily.
    No PHD, but I have a DD 214

  13. #13
    We built a kitchen for some customers years ago and we built it in what used to be their sunroom. It had windows on 3 sides. At the time i had a guy working for me who had previously worked as an hvac guy at the Pentagon. He rigged up a system using a squirrel cage blower pulling air out of the room out through a window and a box fan as an intake on the opposite side of the room. It was the cleanest job site ever! Even when we sanded drywall it pulled 90% of the dust out before it hit the ground.

    Although in my shop setup now i can see that type of setup would be overkill and probably compete with the DC and air filtration. Thanks for the idea, it will give me something to think on while i finish my current project.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •