Dust collection piping questions

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Forum topic by deadherring posted 02-02-2014 09:26 PM 2263 views 3 times favorited 26 replies Add to Favorites Watch
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63 posts in 1609 days

02-02-2014 09:26 PM

I am planning a new dust collection system with 6” PVC. I have never worked with PVC before and have read up on the subject including two books. Surprisingly, although there is helpful info on choosing the right DC, there is almost no info on how the PVC piping and other components need to fit together—maybe they assume people already know this stuff but I have no experience with it.

So, based on the info I was able to find out there I wanted to verify some assumptions about fittings and how the system fits together.
Here’s a sample stretch of my setup—can you all verify that I’ve got this sequence right?

6” PVC pipe—>splice—>6” PVC pipe—>Y split—>6” PVC pipe—>45 degree elbow—>small section of 6” PVC pipe—>45 degree elbow—>small section of 6” PVC pipe—> small section of 6” PVC pipe—>reducer—>4” pvc pipe—> blast gate—>flex-hose—>machine

Did I get that right? Am I right to assume I need a splicer if I am going to connect two pieces of straight pipe? Am I missing any splicers anywhere such as connected to the elbows or Y splits or will those connect direct to the pipe?

Also, I originally had the blast gate on the last section of 6” PVC pipe, but looking around online it seems like 6” aluminum gates are hard to find and more expensive than the 4” gates so I moved it to the 4” section. Is that the right move?

Here’s a sample stretch to a machine with a 2.5” connector:

6” PVC pipe—>-small section of 6” pipe—>6” to 4” reducer—>blast gate—>small section of 4” PVC pipe—>4” to 2.5” reducer—>flex hose—>machine

Did I get those reducers placed right? Also, would I get the reducers from the same plumbing supply house I am getting the pipe from or is that a Rockler (or similar) purchase like the blast gates and flex hose?

Whats the best way to cut 6” PVC? I have a 10” tablesaw, 12” mitre saw, jig saw etc. Altho come to think of it I might not be able to get big stretches of pipe to fit on something like my tablesaw.

I think I will have a lot of cuts to make so the fastest method would be good. What is the tolerance when cutting the PVC in terms of it going together ok on getting an exact cut vs. a little sloppy? If I need to use something like the jigsaw I’m a little nervous about getting great cuts. If anyone has any tips on that let me know :)

Anyway, lots of questions here, appreciate the insight, I’m at the point where I’m hoping to verify the above and then place the order for the pipe and fittings and then do a bunch of praying when I go to put it together and route it around fixtures, plumbing pipes etc in my basement shop :)


26 replies so far

View Fred Hargis's profile

Fred Hargis

4954 posts in 2459 days

#1 posted 02-02-2014 10:45 PM

Your first series is the way I do most of the stuff that HAS to go to 4”. I encourage you to increase every port possible to 6”, and don’t plan on much for those that have 2.5”. As for the “splice” (I think that’s a union) some thinwall PVC pipes have one bell end that forms the female connector, so you don’t need a union in that spot. The purchased blast gates, at least the plastic ones, aren’t that useful (IMHO). They don’t open all the way, and they are cosiderably smaller than the pipe size they’re made for (they also don’t fit PVC very well). Consider making your own, it’s easy and you wind up with a better gate. (here's a starter link). Finally, cutting PVC does nor need to be precise, there is as much as 2 1/2 ” (+/-) overlap in the joints. It’s easily cut on the machines you mention, but it might be easier on the long pieces to just use a sabre saw. Mark a line around the pipe and cut to it. Do be sure to clean up the fuzzies on the cut, though.

-- Our village hasn't lost it's idiot, he was elected to congress.

View deadherring's profile


63 posts in 1609 days

#2 posted 02-02-2014 11:02 PM

Thanks Fred. Interesting point re: the blast gates. I’ve read that the plastic gates are to be avoided and had been planning to go with aluminum gates—it was going to be one less thing to be worried about when it came to setting up the system. Do you know if the aluminum gates are much better than the plastic or would your advice be to go with building my own regardless?

Also—for a newbie—is a sabre saw a jigsaw or a sawzall like in this picture?

View MrRon's profile


4718 posts in 3209 days

#3 posted 02-03-2014 06:01 PM

I found the best and safest way to cut 6” PVC is with a Japanese pull saw. I tried a bandsaw once and the pipe spun around and left me with a deep cut. A reciprocating saw will also work. I use PVC pipe that is made for sanitary and waste service. It is a thinner wall pipe (sch 35) and come in bell and mouth ends in 10’ lengths. You will have to come up with cobbled up fittings to connect it to flex hose and blast gates. Many folks use this type of pipe as it is less expensive than DC pipe.

View Fred Hargis's profile

Fred Hargis

4954 posts in 2459 days

#4 posted 02-03-2014 06:21 PM

You could use a sawzall, but it will probably leave a rougher cut. I was referring to a jigsaw (sabre saw gives my age away, I guess). With a jig saw you do have to plunge cut to get started, but if you have a long enough sawzall blade you wouldn’t.

-- Our village hasn't lost it's idiot, he was elected to congress.

View 49er's profile


171 posts in 1570 days

#5 posted 02-03-2014 07:44 PM

Deadherring,I went through all this last winter and now have it figured out. I used 6’’ pvc schedule 30 I believe, thin wall stuff anyway. I just connected the pipe to the fittings with three or four small sheetmetal screws. I have had zero problems with static electricity. I ran 6’pipe all the way to each machine when I could. Some machine required two points of suction. I made all my own blast gates. A little time consuming but not bad. I mostly use quarter inch plexiglass as a slide with the body out of one inch plywood or half inch phenolic, because that is what I had.
The Y’s are kind of pricie at about $15.00 but the other fittings are reasonable. I cut most of the pipe on a 16 inch radial arm saw but a jig saw works too. I will be glad to answer any question. Oh, I don’t think I used any 90’s, I used two 45’s instead.

-- Correlation is not causation but I did loose my Doctor !!!

View MedicKen's profile


1612 posts in 3428 days

#6 posted 02-03-2014 10:00 PM

Sandor Nagyzslanczy(sp) has a book out called Dust Control in the Workshop. Get it and read it. There is a lot of good info there and the pros and cons of using PVC. I personally will never use PVC do to the fire hazard. I know this will open a can of worms but in my area with hot, dry conditions the possibility is very HIGH of an explosion.

-- My job is to give my kids things to discuss with their

View bigblockyeti's profile


5093 posts in 1686 days

#7 posted 02-03-2014 10:11 PM

A sabre saw is referring to a hand held jig saw, not to be mistaken with a scroll saw that can sometimes be referred to as a jig saw. The “sawzall” in the picture is a reciprocating saw, only Milwaukee makes sawzalls as the name is trademarked. You’re as likely to find a Bosch sawzall as you are a Ford corvette!

View MJCD's profile


540 posts in 2337 days

#8 posted 02-03-2014 10:56 PM

I just finished converting my shop from 4” to 6”, and installing a Clearvue CV1800.

Clearvue strongly recommends ASTM 2729 thin wall drain & sewer piping – though difficult to find (Cresline is a source manufacturer), it is exceptionally easy to work with. In thickness: lightest to thickest – #2729, #3034, Schedule 30, Schedule 40: there is a schedule 80, and you’d have to be nuts to use this stuff.

I used both a hacksaw and my bandsaw to cut the materials – the bandsaw made easy work of the material – regardless of how you cut it, draw a line around the circumference, and follow it!

Flex hose takes you to the equipment: I ran into real problems here, but only due to a bad batch of flex hose: Wynn Environmental and Rockler provide great stuff: I purchased through Wynn, and am very pleased with their customer service and support.

In between these, you need connectors – get 6” HVAC connectors into the flex hose, coupled to 6” HVAC conduit will do the trick.

If I can be of further help, e-mail my LJ account.

-- Lead By Example; Make a Difference

View pmayer's profile


1026 posts in 3031 days

#9 posted 02-04-2014 02:53 AM

I use a jig saw to cut PVC. It works great. I really like the blast gates from Clear Vue. They fit perfectly on the outside of 6” PVC, they seal well, and they hold up. Metal ones are a good choice as well, but they leak much more than the CV ones.

The PVC plans that you described sound fine. The best suggestion that I would offer is to get plenty of extra pipe, fittings and blast gates, and have a general path laid out, and start putting it together. It’s easy enough to reconfigure a bit as you go, but you probably won’t have to do much.

You might find a few ideas for PVC ducting here:

and here

-- PaulMayer,

View HuckD's profile


311 posts in 1680 days

#10 posted 02-04-2014 04:17 AM

I want to second what 49er said about using screws to attach the fittings to the pipe. There’s no need to glue this all together. In most cases two screws will be all you need. You don’t have to pre-drill the holes. The sheet metal or short pocket screws will go right through it. I used some plumbers strap to support the pipes hanging from the ceiling. I’ve had zero problems with my pvc ductwork and it’s been very easy to reconfigure when I’ve added or moved tools. I have had a couple of the plastic blast gates to fail and will now go click on the above link to shop made ones….

-- Visit my Youtube Channel:

View hoosier0311's profile


706 posts in 1991 days

#11 posted 02-04-2014 04:06 PM

I’m certainly no plumbing expert, so I’ll tell you how did it and you can do your thing from there. I used 4” pvc for the whole thing. My dust collector had 4” piping so I figured it would be best. I wish I had done it all in 6” and necked it down at the collector and at the equipment. I ran a trunk line from the DC across the center of the shop and used “Y” to branch off. (I’ll post a picture later tonite). It works very well for the planer, jointer and Radial arm. I necked it down to 2 1/2 for the table saw, and that doesnt work well at all, I’ll be taking that branch up to 4’ like the rest of it when time allows. I used the plastic blast gates, they seem to work OK for me. I have a home made seperator that works OK, but I’ll be doing something better with that in the future as well. Used my sawzall to cut everything, that worked just fine.

-- atta boy Clarence!

View Grandpa's profile


3259 posts in 2641 days

#12 posted 02-04-2014 05:38 PM

PVC is the easiest thing in the world to cut. I have used an old handsaw, a Sawzall, a 12 inch miter saw, a band saw. The cheapest thing you can find is a pull cable. They come at plumbing stores. They are about 2 feet long and have a ring on each end. you wrap the cable around the pipe and pull on first one ring then the other. It makes a perfectly square cut and it is easy. They are cheap too. Keep the pipe large as long as you can.

View Woodknack's profile


11478 posts in 2346 days

#13 posted 02-04-2014 10:29 PM

The cut doesn’t have to be perfect since it will slip inside another pipe and a piece of 120 grit sandpaper will clean up the fuzzies; a Sawzall is easiest/quickest, hacksaw style blades are less mess. I’ve cut shorter sections on a TS sled by butting the pipe against a stop and rotating against the front of the blade.

re: sawzall vs sabre saw vs jigsaw: I grew up knowing a sabre saw was a jigsaw and I have an old jigsaw that is labeled a sabre saw but regardless I was shot down some months back that a sabre saw is “only” a reciprocating saw. It makes sense as a sawzall resembles a sabre (sword) but nonetheless and regardless of what wikipedia says, jigsaws were also called sabre saws. I don’t really care and just avoid calling anything a sabre saw since it’s obviously ambiguous.

-- Rick M,

View Grandpa's profile


3259 posts in 2641 days

#14 posted 02-04-2014 10:43 PM

Yes, sabre saws were sabre saws and a jig saw was like a large scroll saw. We had on in the school shop. It said Delta Jig Saw on the data plate. It used a larger blade than the current scroll saws. At least ours did. A Sawzall is a Milwaukee label. Tigersaw is the same thing made by Porter Cable. I call them reciprocating saws but that could cover a multitude of saws. My shop teacher made us call a table saw a circular saw. It was a stationary circular saw but that was the only saw we had except for the jig saw and it was also stationary. It really bothered me when names began to change. Of course drills are the things we put into the chucks on our drill motors with chuck. I went into a Home Depot and asked where the drills were located and the kid waiting on me took me straight to the drill motors. Oh, Well, old school prevails…...
If you have never tried to cut PVC with a small cable or nylon cord, they are great. Easy and quick. Work in small spaces and they never spin the pipe out of your hand. They leave no burrs. no sanding required.

View hoosier0311's profile


706 posts in 1991 days

#15 posted 02-05-2014 01:59 PM

the picture below, don’t do this.

-- atta boy Clarence!

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