PVC or Metal Duct for Dust Collection

[Travis]

Now that I have a dust collector it is time to pipe it to the machines. I would like to use PVC for ease of installation but hear it is dangerous unless grounded inside and out.

Any feedback on success or failures on the two systems would be welcomed.

Thanks

 

[Bernhard]

Travis,

PVC dust collection is perfectly safe, much cheaper and much easier to install than metal.
The velocities and volumes generated from your average hobby or small shop dust collector is not nearly enough to cause a static discharge that could result in a deflagration of a dust cloud. It's basically a myth.
FWW had an article about that a couple of years(?) ago.
Uless you are running truly industrial equipment (mutli-thousends CFM, very high velocities, long runs) there is absolutely nothing to worry about.

Bernhard

 

[toolferone]

I second that! schedule 20 S&D thin wall PVC is the only way to go.
I got my fittings here.
http://www.mcmaster-carr.com

 

[Alan in Little Washington]

Travis, use thin wall PVC NOT sched 40. While the price of the pipe is not much different, sched 40 fittings are almost twice as much. There are different types of thin wall pvc, the most common is S&D (sewer & drain) which is also called "solid perf". You will also see the thin wall pipe in white, green, and gray. As far as I know all the thin wall stuff has the same O.D. (which is different than the O.D. of sched 40), so the various thin wall fittings are interchangeable. You will see various designations for the fittings- ASTM 2729, ASTM 3034, ASTM 3035, etc. but these all have the same I.D.

It's been over a year since I bought all my DC pipe and fittings, but McMaster Carr prices seem really high. I paid about $13 for a 6" wye. If I was looking in the right place McMaster Carr wants over $20. (FYI, a 6" sched 40 wye is near $25!). You can get both 4" and 6" S&D fittings at many Lowes. Some Lowes even carry the 6" S&D pipe, though mine did not- I got it a local hardware store.

Don't glue the pvc together- friction fit is fine. If you think it needs to be sealed better, put a tiny bead of silcone sealer on the pipe AFTER the pipe is seated in the fitting. That way it can be pulled apart and reconfigured. You can easily rub off the cured silicone with your finger. Don't use any T's- only wyes and 45's. I don't know what DC you have, but recommend using 6" all the way to all your machines.

The PVC spark problem is a myth. Rod Cole, an MIT scientist did the research and is published- here is the link to his article in FWW http://www.taunton.com/finewoodworking/Workshop/WorkshopPDF.aspx?id=2756

and here is Rod's web page: http://www.taunton.com/finewoodworking/Workshop/WorkshopPDF.aspx?id=2756

 

[toolferone]

Alan, When I bought my 6" stuff the big boxes did not have it and the supply houses where Very high. I saved alot of money using McMaster-Carr at the time. ASTM D2729 is the thin wall pipe I used

Use this part#9102K186 on their site and see if this works. It is $10.29

 

[frigator]

My last duct system was all 6in PVC and it worked fine. My only complaint was it shocked me everytime I touched the planer blast gate. For some reason, that ductwork on that tool had quite a shock to it. It got so bad I wouldnt touch the gate, using a skinny board to open and shut it. I could have probably grounded it but never got around to it.

I just ordered a new cyclone yesterday and this one is bigger so I plan on using metal this time. I got bigger machines, a bigger cyclone with more CFM and dont want to get shocked anymore.

 

[Alan in Little Washington]

Alan, When I bought my 6" stuff the big boxes did not have it and the supply houses where Very high. I saved alot of money using McMaster-Carr at the time. ASTM D2729 is the thin wall pipe I used

Use this part#9102K186 on their site and see if this works. It is $10.29

I must have looked in the wrong place. Found it. Interesting difference in price between a wye and sanitary T. And look at the prices for the clear PVC (all sizes) (higher up on the same page). Yikes!

 

[Travis]

Intersting, sounds like thin wall PVC is the way to go now that I do not have to worry about blowing the house apart with a 2 hp cyclone. (I had visions of a grain elevator explosion in my basement.) I really appreciate the advice. Friction fitting with silicon seal was an excellent suggestion. I would have glued it all up. :eusa_doh: