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Thread: Dust Collection help

  1. #1

    Dust Collection help


    Currently i have a harbor freight unit with a similar setup as here:

    I have 10 foot ceilings in my 20x20 detach garage. one side of the garage has a stairway where i built a wall to hide and sound proof this unit and exhaust it outside. To allow for access to the tools on the opposite side of the garage i installed PVC along the ceiling. I didn't even think of it at the time but the vertical rise sees to have had a pretty extensive affect on the suction. so much so i keep the blast gates closed and use a small shop vac to aid in some of the collection.

    My question is if i were to buy the 3hp grizzly unit below and modify it to use the same setup as above will i have enough suction to use the tools on the far side of the garage? Changing the layout of the piping isn't an option as i have a garage door and stairs on the one side and the opposite side of that wall a number of windows and doorway so the way i have it i think is ideal. Just not ideal for this unit.

    What do people think?


  2. #2
    Join Date
    May 2012
    Gatineau, Québec
    Hello Aaron,

    I run my system (CV1800) in a 10 foot ceiling smaller (14 x 20) shop, using 6 inch conduits. Granted the unit I am using is more powerful than the proposed Grizzly unit, it should be feasible to solve your problem.

    Could you please provide a little more background on your setup, including :

    - the diameter and length of the current pvc conduits, as well as elbows?
    - whether you have noticed the performance degrade over time or has it remained constant (low)?
    - what is the difference in terms of power between your current unit and the proposed Grizzly unit?

    This should help colleagues to provide you with workable options.


  3. #3
    Join Date
    Nov 2007
    Crown Point, Indiana
    The system you linked to has a 12.75" impeller. The cfm given for it is 2300 and not credible. Will it be better than the HF...yes.

  4. #4
    Join Date
    Mar 2015
    Birmingham, MI

    Your proposed Grizzly will provide significant more air flow. As Larry mentioned the Grizzly impeller has a 12.75 diameter (vs 10" on HF) and it is much taller. However, as Jacques asked, we need more information about your ducting. If you are using 4" PVC it will severely limit your flow, especially over a longer run (even if you upgrade). Take a look at Andy's setup. It is in a larger shop where he uses 6" PVC and has some serious airflow at all his stations (even when you take into account it is measured with a handheld meter).

    Larry has found a source that indicated a Super Dust Deputy will add 2-2.5" of SP to your system and if you are using a Thien baffle it is probably a bigger SP loss. Add that to your long duct runs and you will have the limited airflow you describe.

    If you can provide more information and pictures of your setup that would be helpful.
    Hope this helps. Let Us know what you do.


  5. #5
    Join Date
    Feb 2013
    Tippecanoe County, IN
    Aaron, you can make a ballpark estimate using the Fan Affinity Laws. Increasing the fan diameter from 10" to 12.75" should cause the flow to increase by a factor of approximately 1.275 or 27.5%. Velocity pressure will of course increase by the square of that factor or about 63% so the flow should "feel" that much stronger.

    If your setup is like that in the video but without the rat's nest of flex the HF blower be able to pull about 350CFM through 40 feet of 4" PVC and four 90s if the inlet has reasonable losses. A bigger fan would then give you about 450 CFM. Add the flex and 350 could become 250.

    Quote Originally Posted by Carl Kona View Post
    ..Larry has found a source that indicated a Super Dust Deputy will add 2-2.5" of SP ...
    Carl, do you know at what CFM that pressure drop was measured? Do you have a link to Larry's source?
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  6. #6
    Join Date
    Oct 2005
    Helensburgh, Australia
    Quote Originally Posted by Larry Frank View Post
    The system you linked to has a 12.75" impeller. The cfm given for it is 2300 and not credible. Will it be better than the HF...yes.
    Wishful thinking at best and is not going to happen. Buy the one with the biggest impeller, simple, no other consideration needed and don't believe the flow figures for any of them.

    Everything I like is either illegal, immoral or fattening

  7. #7
    good money after bad IMO.
    Minimal improvements if what you have now is inadequate to the extent that it can't pull chips and dust up your drop...

    I'd suggest to simplify your layout, ie. reduce sp, for now and save up for a better system that will do the job. Alternatively, watch the used market for a blower/cyclone that will do the job for the price you see the grizzly at...

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