PVC vs Metal Duct

[sbarton22]

I just got my dust collector wired and running. I'm pretty amped about the whole thing...so much that I now want to run a trunk line in my joists to collect from another part of my shop.

My question is this...can someone give me a few pros and cons of PVC vs Metal duct?

I understand that I need to run some grounding wires in the PVC. Doesn't seem like a big deal. Would I need to ground metal duct?

Any advice here would be greatly appreciated.

 

[sbell111]

If the Mythbusters are to be believed, grounding PVC is not necessary.

 

[OKLAHOMAN]

I've run PVC fot the last 4 years, ungrounded.

 

[MarkD]

If you do a google search you will find lots of information on this subject.
I found a local HVAC shop that made metal spiral pipe so I went that method.
No grounding is required for metal pipe.

 

[Andrew_K99]

PVC is quick, easy and cheaper to set-up but finding the correct connectors isn't alway easy. The deflection points tend to be too tight and aren't ideal for flow. It is suggested to use two 45° elblows to create a smoother 90° bend. Blast gates aren't readily available either.

Metal ducts (not the home store HVAC ducting!) offer more options for layout as you're not using product designed for something else. But this costs more.

AK

 

[MesquiteMan]

I have been running mostly 6" with some 4" PVC for 14 years with no grounding wire and no issues whatsoever. PVC is less expensive I think thought that is not why I went with it. It is easier to work with and easier to modify when you make changes.

 

[sbarton22]

I've read so much conflicting information on grounding PVC, which I guess is not actually even possible because PVC is an insulator, and you can't ground an insulator. I'm looking at about a 20' run and wyes on either end at the drop downs. Pretty simple set up. I have read that you are not able to build up enough static in 4" trunk @ 20' to ignite. However, if I run some aluminum through my bandsaw, I would have plenty of metal flying around to possibly catch a spark (or am I completely way off??)

I do love the cost and convenience of PVC as a solution.

Now, I'm actually loving the idea of spiral pipe. One silly question...how do you cut it? (maybe that is some of the metal that is flying through my bandsaw?) And do you use metal tape to seal the connections?

I have also read in a couple of manuals that you want to ground metal pipe, but it is much simpler because you can attach a ground at any point, considering metal is a conductor.

Ultimately, I might end up with a hybrid solution with PVC integrated into my tool stands and the trunk of metal pipe.

Lots of good thoughts here. Keep them coming, please!

 

[MarkD]

Now, I'm actually loving the idea of spiral pipe. One silly question...how do you cut it? (maybe that is some of the metal that is flying through my bandsaw?) And do you use metal tape to seal the connections?

I cut the spiral pipe with a sawzall and a fine metal blade. I used a little silicone on the inside of the joints then wrapped them with metal tape.