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Thread: DC Ducting for modded HF 2HP dust collector.

  1. #1
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    DC Ducting for modded HF 2HP dust collector.

    My old Central Machinery 2HP dust collector has been quite heavily modified, and I am considering what, and how to upsize the ducting.

    At present, the configuration is thus.

    2009 ish Central Machinery 2HP dust collector + Wynn .5 micron cartridge filter + Wen impeller + Thien baffle in the DC separator ring.

    I am using the stock 5x4x4 wye fitting on the DC to 2 separate 4" S&D runs, one high, one low.

    I am considering upsizing to a single 5" or 6" main and branching to 4" at the tools.

    Unfortunately 5" is not a common suze for duct fittings at least as I can find online, there is no shortage of stupid expensive dust collector spiral pipe specific stuff, but if I had funds for that, I would be buying a big Clear Vue cyclone. Also 6" S&D fittings are stupid expensive by comparison to 4", at least from what I see online, I need to get my tail to Lowes as that is where I got my 4" as it was cheapest there, and sheet metal fittings are configured for flow backwards to how a dust collector would work.

    Let's say I need the following drops off of the main.

    #1. Table saw blade guard.
    #2. Table saw blade shroud under cabinet (2.5"
    #3. Shared 4" for workbench / benchtop tools / router table fence.
    #4. Router under table enclosure.
    #5. 4" split to dual 2.5" for bandsaw.
    #6. Miter saw cabinet / blade guard.
    #7. Lathe.
    #8. Drill Press / Mortising machine bench. I can move hose tool to tool...

    I am seeing LOTS of conflicting information on if a cyclone separator conversion, like a Super Dust Deputy, or Super Dust Deputy XL compared to a Thien separator, the cyclones allegedly flow better, BUT that shows in separate units, not in the separator ring units. What little info I have on the separator ring units like mine, they say it flows slightly better than say a SDD at least until the filter starts getting dirty, say after 100 gallons of dust. I clean my filter after every dump of the collector, so not sure why that would be an issue. If you have ideas, links, data etc... I would LOVE to see them.

    Anyway, I was hoping to see what ducting options there are that will work well, that may come in at a more affordable cost... But I also want the best performance I can eke out of this little HF DC. And mind you, I can easily swap the inlet flange to a 6" should that be the way to go...

    So ideas on ducting this for max efficiency would be very helpful. As it sits I am thinking I should go with 5" to the existing splitter and stay with dual 4" runs, so I can capture upper and lower. I am just wondering if this is the best I can do...
    Last edited by David Hostetler; 11-30-2021 at 10:25 PM.
    Trying to follow the example of the master...

  2. #2
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    First point - Don't use DWV. That's just a foam core version of Schedule 40 and uses the same fittings. The appropriate spec for DC is ASTM 2729. That's a slightly smaller OD than schedule 40/80 and uses lower cost fittings. Also known as sewer and drain or S&D.

    Second - For your 4" branches use a 6x6x4 wye. You take an expansion loss regardless of where the expansion is and the difference between a 4" 45 and a 6" 45 is (IMO) not worth the extra cost. UNLESS you have a long run of hose then stay 6" for as long as possible.

    Third - Your Thein-in-a-ring is certainly lower loss than a separate Thein separator but still much greater than a SDD XL. You can get a big improvement by getting rid of the ring and going straight into the filter with the SDD on the fan inlet.

    Also, be sure you hack the fan inlet from 5" to 6".
    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.

  3. #3
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    Quote Originally Posted by David L Morse View Post
    First point - Don't use DWV. That's just a foam core version of Schedule 40 and uses the same fittings. The appropriate spec for DC is ASTM 2729. That's a slightly smaller OD than schedule 40/80 and uses lower cost fittings. Also known as sewer and drain or S&D.

    Second - For your 4" branches use a 6x6x4 wye. You take an expansion loss regardless of where the expansion is and the difference between a 4" 45 and a 6" 45 is (IMO) not worth the extra cost. UNLESS you have a long run of hose then stay 6" for as long as possible.

    Third - Your Thein-in-a-ring is certainly lower loss than a separate Thein separator but still much greater than a SDD XL. You can get a big improvement by getting rid of the ring and going straight into the filter with the SDD on the fan inlet.

    Also, be sure you hack the fan inlet from 5" to 6".
    Absolutely plan on going with a 6" inlet. And I already have a Thien in place. Not sure how this has more resistance than a SDD XL. I'd like to see side by side comparisons... If for no other reason, removing bends helps...

    Thanks for the clarification, and I definately misspoke... Yes S&D, not DWV...

    Looking around just googling Super Dust Deputy XL vs Thien Baffle brings me to several conversations on the topic, including the one here https://sawmillcreek.org/showthread....s-Thien-baffle

    Looks like the Thien actually produces less of a CFM drop than the SDD XL... Like others have mentioned, up to 100 gallons of dust, then when the filter gags up the SDD gets the advantage. I clean the filter every time I dump the bag so I don't think I am in excessive loss territory here.

    Mind you, if I were looking at scratch building a proper cyclone and not upgrading a Harbor Freight DC, I would seriously consider the SDD XL, plus a proper 3HP motor / impeller, and a filter with a clean out box at the bottom. For now, the cart format of the HF DC is what I am looking for... Not saying it's perfect, ideal or anything, just what works for ME...
    Last edited by David Hostetler; 11-30-2021 at 6:54 PM.
    Trying to follow the example of the master...

  4. #4
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    Okay more dig dig dig. I am going to update in the first post just to make sure that new readers catch what I am thinking...
    Trying to follow the example of the master...

  5. #5
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    Okay continuing to go over the Pentz documentation, and posts here, and at several other WW forums. I am coming up with the following thoughts.

    #1. The 2HP motor / impeller is more or less maxed out with 5" duct, but 5" duct and components are not super easy to find. I have doing some digging found that under the WoodRiver brand, there are 5" wyes, and 5x4" reducers are prices not much worse than 4" S&D fittings. HOWEVER the duct itself is the big question mark. I do not know, but it might be worth checking to see if relatively inexpesnive 5" split duct would work with these fittings.
    #2. For chip, and the majority of fine dust separation in a single stage dust collector, with a minimum of CFM loss, Bill Pentz recommends a Neutral Vane in the separator ring.
    #3. I am not anti SDD, but I am trying to avoid a full on 2 stage conversion in the garage and postpone it until I move to the dedicated workshop building.
    #4. My Wynn cartridge filter is a fixed top model. Not sure how I would convert it to use for output of a 2 stage without a separator ring. Probably cut a hole for a takeoff flange in the top, fix the flange, and build / attach cleanout box for the open end of the filter.

    So this leaves the question, has anyone used the ABS 5" dust collector fittings on 5" split duct and how to you get the two to play together nicely?
    Trying to follow the example of the master...

  6. #6
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    Don't discount using 26 gauge snaplock steel duct. Easily available in one inch increments (check with your local HVAC suppliers). Many of us have used it very successfully without issue, 10 years in my case.
    https://sawmillcreek.org/showthread....all&highlight=
    NOW you tell me...

  7. #7
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    For commonly available PVC/ABS pipe, you'll only find "even numbers" for sizing. It's been said that there is 5" electrical conduit available in some cases, but I've not checked that out and personally stick to metal duct work. So for your situation, the most practical setup might be to do the 6" main with 4" drops. Folks who have done that often put a retrofit collar on the blower to increase it to 6" from 5".
    --

    The most expensive tool is the one you buy "cheaply" and often...

  8. #8
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    Quote Originally Posted by Ole Anderson View Post
    Don't discount using 26 gauge snaplock steel duct. Easily available in one inch increments (check with your local HVAC suppliers). Many of us have used it very successfully without issue, 10 years in my case.
    https://sawmillcreek.org/showthread....all&highlight=
    +1. Especially for less powerful DC. I used common HVAC duct with a clearvue for years. 6" metal. It worked fine. One thing that helped was the hanging brackets were fairly stiff and wrapped around it and helped maintain the shape if placed not too far apart. The elbows and 4" dia sections were not an issue at all.

  9. #9
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    I think I need to haul my tail into the local BORG, and possibly the plumbing / HVAC supply house to see what fittings are available for 5" snap lock ducting. Hangers are no big deal, readily available, the pipe itself is readily available and cheap, it
    s the wyes that are problematic. MOST of them are set up with say a 5" inlet, and 2 4 inch outlets. I need a 5x5 with a 4 inch branch, OR a 5x5x5 and a 5x4 reducer.

    I would assemble with rivets and aluminum HVAC sealing tape.

    Like I think I mentioned above, It looks like from the Pentz charts, 6" is too big for a 2HP motor / 12" impeller. I should stay with 5". That's fine with me if the components are available.

    So project phase for right now. Do the neutral vane, get rid of the Thien baffle. Sorry Phil, I want to try it out. then the DC machine itself is as done for now as it will get.

    5" elbows set to make long sweep to get out of impeller housing and into main up the wall to the ceiling, and along ceiling , then first 5x5x5 wye, straight along wall, and at a 45 to go across to the workbench / table saw. Then 5x5x4 wyes, or 5x5x5 wyes and reducers to get to 4", then 45s, down the wall to the blast gates, and short segment of hose to the tool.
    Trying to follow the example of the master...

  10. #10
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    to convert sheet metal wyes from hvac to dust collector mode. I clamp a 2x2 to work bench hanging over edge, slide the factory crimped end on and use a ball pein hammer to remove the crimp. Then hand crimp for dust collection, all other parts work ok installed in dust collection mode.
    Ron

  11. #11
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    David, there are generally multiple options for 5" wyes, but keep in mind that they are designed for HVAC flow direction which is the opposite used for dust collection. That means you'll need to modify the crimping, etc. You may want to check with an actual local HVAC supply to see if they can provide wyes that are easier to use or contect places like Air Handling Systems, and some others that have been mentioned here from time to time for good DC components. The 'borg is also unlikely to have long radius elbows.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
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    Quote Originally Posted by Ron Selzer View Post
    to convert sheet metal wyes from hvac to dust collector mode. I clamp a 2x2 to work bench hanging over edge, slide the factory crimped end on and use a ball pein hammer to remove the crimp. Then hand crimp for dust collection, all other parts work ok installed in dust collection mode.
    Ron
    Well, given the cost difference, and reported performance given a VERY similar layout to my intended application, I am thinking of going with 6". The shop is 20' long, DC is 24" from the wall to the inlet, and last port will be 24" or so from the end wall. The overhead duct run will fork off at the outlet and 45 over maybe 6' of duct, then the drop... So up and over maybe 10' total?

    So I know all about hammering out the crimps and crimping the opposite end. Take a piece of 6" and use it to draw the radius on a hunk of 2x6. And hammer out the crimps. I have an HVAC duct crimper that I used on the Thien separator I had. Only way I could get a 5" port that was only 6" long was to fab one up myself, and I had to make it fit in my hose...

    So yeah, i am going to be going with 6"...

    I am going to do a thread on the upcoming workshop build...
    Trying to follow the example of the master...

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