# 7 inch dust collection ducting?



## BannorToys (Dec 12, 2013)

I recently bought a Grizzly 3HP double canister dust collector for my new wood shop. It turns out that the inlet is 7 inches and I am having a heck of a time finding any piping and fittings that will work with this size of an inlet. I think PVC only comes in 6 or 8 inch and I'm not sure about easily obtained metal duct work? Also, I need to have elbows, straights, and Y type fittings. Of course a lot of my machines have 4 inch ports so I need to be able to reduce at the machine, not sure if metal ducting has options for this?

I found a few places online that want what seem to me to be crazy amounts of money for the fittings so I am wondering what you all use? I really don't want to take it down to 6 inch unless I have to. I want to do it right (this is my huge dream shop I'm building here) but I don't want to spend as much on 40 foot of pipe as I did on the machine itself. Any help is appreciated, thanks in advance!


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## wapakfred (Jul 29, 2011)

Deleted, it was a double post.


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## wapakfred (Jul 29, 2011)

Mine has a 7" inlet, and Oneida suggested I run 7" for at least the first 5-6 feet before transitioning to 6". So I used 7" HVAC snaplock and 2-7" HVAC el's to run the duct up to the ceiling, then transitioned to 6" PVC. If you choose snap lock, be sure to get the heaviest gauge you can get; a lot of guys have collapsed the 30 gauge stuff. The transition to PVC is fairly easy to do, though it's not particularly attractive. A 7×6 HVAC transition (reducer/enlarger) will do it, as for the appearance I'm a function over form guy (really don't care what it looks like). Here's what I did to my drum sander to get a 6" port on it. Like I said I function over form, and this works really well.


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## shipwright (Sep 27, 2010)

This is the second time in a couple of days that I have posted this reference. It is a good solution to the high cost of fittings.


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## descolada (Jun 23, 2013)

I had the same problem looking for 7" duct in my system recently. If you want to go the sheet metal route (as i did) penn state has pretty reasonably priced. I bought my system using their economy line and it it was a bit of a pain trying to connect everything using duct tape, but worked great once installed. You can find it here: http://www.pennstateind.com/store/economy-ductwork.html

When I went to expand the system I used their economy pieces except i switched in the premium drawband connectors. At 7" they are $20 each instead of $10, but much beefier and easier to install.


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## Finn (May 26, 2010)

I put in a six inch system all of 24 gage steel. I am a retired sheet metal worker so I made the wyes myself and bought the ells. You could get a sheet metal shop to make a taper for you to fit PVC and use PVC from there to the equipment. It would be one rather expensive fitting but only one.


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## copcarcollector (Aug 8, 2012)

I have that exact dust collector. I ran a small amount of 7 inch metal pipe to turn the corner and go up wall, then used an adapter down to 6 inches for all of the main runs and drops.


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## BannorToys (Dec 12, 2013)

Having the exact same dust collector, how do you like it so far? I haven't used mine yet


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## Holbs (Nov 4, 2012)

i'm in the process of doing all this myself. gots a blog going with building a Thien Baffle (still in progress).
Everyone that has a grizzly 3HP dual canister says they have 7" inlet. While mine is 6". 
I was lucky.. I have a friend at a HVAC distribution supply house. I get my 6" why's for $3 and snap lock 5' for $7 (all 26 gauge).
Was about to fiddle with the wye's… then I found out they are facing the wrong direction. Unsure what to do about it! Grr…


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