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Thread: Follow-up: Central Shop Vac System

  1. #16
    Join Date
    Jan 2008
    Location
    Colorado
    Posts
    441
    Charles is contributing an interesting data point with the collapsing dist bin. I suspect central vacuum power units might offer the greatest amount of suction of the three options: (1) central vacuum; (2) "inexpensive" shop vac; (3) Festool/Fein vac. From my experience, I think suction is far more important than flow for a vacuum solution that's used primarily for handheld power tools and general shop cleanup. Given my arrangement with central vac plumbing, Dust Deputy and Fein vacuum, if I did not have enough volume, my plumbing would start to clog. What I think I'm lacking is enough suction for the tools producing the most "dust".

    Have a look at the following reviews of vacuums where the reviewer uses a water column gauge to measure suction of the Festool vacuum compared to cheaper shop vacs.
    https://www.youtube.com/watch?v=1y1GUH83N1s
    https://www.youtube.com/watch?v=LOI_Ia55ULs

    The Festool vac does produce more suction on the gauge. If published specs of some central vacuums are accurate, they produce even more suction than the Festool vacuum.

    The other variable in this equation is the Dust Deputy. I suspect it is significantly contributing to suction loss. Maybe cyclones experience considerably more inches of water lift loss than CFM loss. I'm thinking of getting hold of a water column gauge to test this myself. Has anyone run across any articles or videos on the web that quantify Dust Deputy suction losses? Central vacuum plumbing also contributes to suction loss. Between the central vac plumbing and the Dust Deputy, I might be losing too many inches of water lift to effectively use a shop vac, even the most powerful ones available.

  2. #17
    Join Date
    Nov 2003
    Location
    Central North Carolina
    Posts
    1,830
    Sean, the central vacuum plumbing does reduce the flow, but without a water column measurement of the suction at the vacuum unit as well as at the machine I can't provide a good digital comparison. With no flow the water column measurement in all locations of the piping should be the same, but when a port is open and there is flow, the plumbing most certainly affects the vacuum level at different points. With an open port at or near the vacuum I think one of these central vacuum units could suck your shorts right off of you under the right conditions.

    When I first got my central vacuum unit repaired and running, I tried connecting my hand held DeWalt ROS direct to it. The vacuum was very effective at collecting the dust, for a few minutes, and then the fabric filter in the vacuum began clogging. In about 10 minutes, the flow was so bad that it was leaving sanding dust on the board being sanded. That's when I decided to get a Dust Deputy to use with the vacuum and not depend on the filter in the vacuum at all. On receiving the Dust Deputy I first had it hooked up to my Shop Vac with a white 5 gal plastic bucket from Lowes under the Dust Deputy mostly so I could test how well the Dust Deputy separated the saw and sanding dust from the air. The combination worked quite well and I was impressed with how well the Dust Deputy separated the dust and put it in the 5 gal bucket. The bucket didn't collapse either, until I decided that this Shop Vac/Dust Deputy arrangement was always in my way in my small shop. That's when I decided to install the central vacuum and Dust Deputy in the attic of my shop and the central vacuum plumbing in the walls and ceiling of my shop. After completion and the first time that I used it is when I had the imploding bucket problems, not with a free flow through the hose and pipes, but when the first large wood chip partially plugged the end of the hose while vacuuming the shop floor.

    Again, this isn't a perfect solution and not a true wood shop dust collector, but it works very well for collecting the workbench sanding, 6" bel/12" disk sanding, scroll saws, drill presses, band saw, and floor vacuuming in my small shop where I don't have the room for a real wood shop dust collector in my small shop. Since this central vacuum has been working so well for collecting from these fine dust producers in my shop I think that if I ever have a larger shop I will still have my central vacuum/Dust Deputy combination installed for the smaller saw dust producers just like I have now, as well as a large dust collector for the high volume chip producing machines like the Unisaw, jointer, planer and wide belt sander (if I ever get one).

    Charley

  3. #18
    Charley,
    It seems you have a great setup for you. That iss what we all try to get to. No criticism intended by my previous post or this one, just thoughts and other experiences. I appreciate you sharing yours. I get good suction with my Rigid shop vac dust deputy combination, even through my 20 foot and 5 meter hoses. I don't know what the inches of mecury or water is for this combo but I know it picks up the chips and dust well which is what counts. I was not sure I would with a 20 foot long flexible 2.5 inch hose (available for about $20 at home depot) but it works. My shop is only 14x24 so I am tight on space which is why I sold my DC. I have the vac/cyclone on a little cart that has been modified several times. The current configuration has the vacuum under the cyclone and is about 20 inches wide and 2 feet deep. It sits along the wall where I crosscut and have lumber storage. The tall part is close enough to the wall that it does not impede CMS or RAS use. So I found space for it. I agree it is loud but it isn't as loud as most of the tools it gets hooked up to. So I am wearing muffs anyway and the noise is not an issue.
    I'd like to not have to empty the drywall bucket as often but I do not have space for a larger container in the shop. The space above the shop is a bedroom. So my setup is a compromise too but one that is working fine for me.
    My biggest related issue was the use of my old Rockwell speed block. That sander was offered as a Porter Cable last time I looked but mine is before that switch occurred. I rarely use it now because it does not have provisions for dust pickup. I was sanding some panels with a cove cut on them, however, and the soft pad of the speed block works well for that. I had forgotten how much dust this creates, however. It made my appreciate my normal setup more. While a compromise, it really helps keeps the dust down.
    Jim

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