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Thread: Piping new-to-me DC

  1. #46
    I'll try to answer one of Anthony's original questions albeit a few months late.

    I transitioned from 6" 2729 PVC to my 2HP Jet cyclone inlet (~5-7/8" OD) with a turned adapter. I was all jazzed to buy a 3D printer for this task when I realized that my lathe is more than capable of making cylinders... darn common sense got in the way of a fun tool.

    DC-Adapter.jpg

    I made a series of plywood rings (bandsawn circles with middles cut out with a jigsaw) and glued them into a stack and then glued that onto a waste block. Then I hollowed out the two halves with the appropriate ID using my Elbo hollowing tool.

    The 6" (nomimal as heck) Fernco fitting I found at the hardware store is designed to fit around 6" clay so it was quite sloppy even around the PVC. Fernco's better sized to this application were $40+ from plumbing suppliers.

  2. #47
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    If the duct work is over sized, then the dust will fall out an collect in the duct. I would think there would be a 'terminal velocity' type aspect involved. If you have a a DC that can only support 6" duct and you install 8" duct, dust will collect in the pipe until there is 6" pipe worth of opening. The 8" duct with 50 sq in opening would be reduced to 28 sq in (6" duct).

    If you can't have the exact right duct size, is it better to be the next size lower or the next size larger?
    Last edited by Anthony Whitesell; 11-30-2020 at 8:21 AM.

  3. #48
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    Quote Originally Posted by Anthony Whitesell View Post
    If you can't have the exact right duct size, is it better to be the next size lower or the next size larger?
    I'd go next size higher, with the qualifier that I use metal duct which is available in 1" increments. My 2hp Oneida system has a 7" port and I have 7" duct out to the major branch for the main and 6" from there. I'd settle for some slight settling over restricting max CFM...but that's a personal point of view.
    --

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

  4. #49
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    Quote Originally Posted by Jim Becker View Post
    I'd go next size higher, with the qualifier that I use metal duct which is available in 1" increments. My 2hp Oneida system has a 7" port and I have 7" duct out to the major branch for the main and 6" from there. I'd settle for some slight settling over restricting max CFM...but that's a personal point of view.
    That was what I was thinking but wanted to check if there was something I was overlooking or not considering.

  5. #50
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    I'm thinking 6" PVC is the way to go. If oversized, dust will only settle to some terminal amount.

    6" flex and 6" hoods would be overkill. Is there really that much difference between a 5" and 6" port on a 12" planer? Plus I have 5" flex on hand. I can make my own 6" PVC blast gates, with quick connect fazloc style couplings easy enough. I really only have one issue left (besides an inexpensive local source for 6" PVC LOL).

    Is anyone running 6" PVC with 5" flex to the machine? How did you go about making the transition?

  6. #51
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    I have pretty well decided to use 6" PVC with 6" home made (and eventually automated) blast gates. The given the DC specs say it should be able to handle 6" duct, as many have said the ratings are probably over stated. I would expect the DC to run 5" duct like a champ. I'm going with 6" to reduce friction and SP loss and I will deal with whatever settling occurs in the horizontal runs.

    I will be using the DIY trashcan separator with the baffle and center outlet. Eventually I'm thinking I should switch to the Oneida Dust Deputy. First off, it would make the trash can able to hold more (changing from working as part separator-part bag to working as all bag) and secondly the dust deputy probably works better than my trashcan version (less SP and CFM losses). I'm leaning towards the 5" version based on the above and the below.

    I was gifted many many feet of 5" flex to connect to the machines. I'm sorry to say, I'm not modifying the integrated cover to my $1200 drum sander (it will stay 4").

    I have a few things left to figure out.
    1. Assuming I go with the 5" Dust Deputy. I will use a metal transition from the 6" DC to the 5" flex to the dust deputy. That leave the dust deputy inlet side. How do I convert from the 6" PVC (6 5/8" OD) to the 5" flex hose for the dust deputy inlet?
    2. Same as #1, only from the blast gate to the hose to the machine. No matter how show the hose is, it is still hose, and still needs a connection.
    3. Dust hoods. The bandsaw needs a 544 wye, hoping I can find one. The drum sander will stay 4". I need to make 5" dust ports on the jointer and table saw. I prefer something with a thicker edge than sheetmetal, I've already cut myself just looking at the fittings. Nordfab is so tempting but twice as expensive as tempting.

    Any thoughts or links on these last few items is appreciated.

  7. #52
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    If you can retrofit the inlet on the blower to 6" and keep everything at 6", you may have better performance than with the transitions from 6" back to 5". The cyclone is already going to add some performance degrade to the setup (which is normal). Many DC's have a removable flange on the inlet of the blower which you can replace with a slightly larger one. Lots of folks have done this over the years.
    --

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

  8. #53
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    The blower inlet is 6" already. But as mentioned by others, the DC likely cannot support 6" at the correct CFM. Getting a 6" dust deputy is not out of the question. But as cyclones are sensitive to airspeed, I am hesitant if the DC will be able to run within the airflow range (no idea what that range is) of the dust deputy.

    That would add question #4. How to transition from 6" PVC to 6" flex (or 6" metal duct)? The transitions from the PVC to the flex hose are my current hang ups before pulling the trigger on buying stuff.
    Last edited by Anthony Whitesell; 12-07-2020 at 2:06 PM.

  9. #54
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    One method to transition from the plastic to the hose is to get some flat sheet metal and cut a piece that you can make a sleeve that slips into the plastic duct, get fastened with screws or pop rivets. The hose can then be clamped to the insert securely.
    --

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

  10. #55
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    I'm still stumped on how to use PVC duct and DC flex hose. At some point you need to use flex to get to the machine, or at least I do since I have to move everything around.

    There was one suggestion to get from 6" PVC to 6" flex by using a 6" metal duct piece as a inner-coupling. I'd like to stay with 5" flex since I have it and think 6" flex will be too much for the DC based on prior comments.

    Which type of duct do the 5" metal blast gates fit?

    Which type of duct do the 5" abs gates fit? Slightly important seeing as they don't make many 5" abs fittings.

  11. #56
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    You can use a metal reducer, perhaps with some modification, to get from your 6" plastic duct to 5" flex. The typical black ABS blast gates are not necessarily sized for hard pipe just like the other black dust collection fittings sold in woodworking stores...they are "ancient things" and often sized to work just with flex hose on both sides, which is inefficient. A lot of folks make their own blast gates for plastic ductwork.
    --

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

  12. #57
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    Don't overthink it. Go buy a couple of 6" pre-crimped stove pipe couplers at the hardware store. Then drill out the rivets. Add a little english to the connections you need to make (perhaps with a few german expletives), then wrap it good with some foil tape and you are done. Ready to make some dust!

    Sheet metal is plastic...I used to bend sheet metal for a living. These stove pipe couplers with foil tape are the fastest way to make a duct connection on a DC system like this. Because it is all pre-crimped on both ends and you are just rearranging it a little bit making it fit. Who cares if the fitting is black?

    I went through this scenario with my HF DC to Super Dust Deputy 2 stage and it worked brilliantly. Also, if the end of the pvc elbow is 5/8 too big, it needs a small section of pvc pipe put into it as a coupler. I use 4" SDR35 green sewer pipe in my system, with powertec-style black couplers and blast gates, and it all fits together magnificently with the green sdr sewer pipe. It all fits so well that I seal my duct connections with one (1) wrap of black electrical tape. You read that right.

    Furthermore, if you have not tried it much, know that PVC pipe is ultra plastic and can be very easily stretched over larger fittings if you heat it up. I make all my own vacuum hose couplers out of PVC by heating with a cheap HF heatgun and working it over the fitting. Don't make it smoke...not that hot. It isn't crack; it's polyvinylchloride. But you can work magic with this technique. These homemade fittings are some of the most beneficial things in my shop.

    My $.0.02. I hope it helps someone.

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