# PVC vs Metal DC ducting



## JollyGreen67 (Nov 1, 2010)

I am in the process of working up a plan to duct my DC, and wondered about the druthers of PVC vs Metal. If I use PVC all the joints must be glued. And, the metal will have to sealed with metal duct tape, not that crap cloth stuff that some people think is duct tape, to seal the joints. No matter what I use, it will be attached to the wall in my itty-bitty shop - 2/3 of one bay of a 3 bay garage. All the machines that will be hooked to the DC are down one wall with mobile bases. The only thing that will be on the floor will be the hoses, and then only when the machines are in use, as I plan to drape them from the wall, to keep them off the floor when in not use.


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## jusfine (May 22, 2010)

I just did a search PVC vs Metal ducting in the little search bar, it returned a number of pages of results.

You may find some wisdom there…

I installed metal in my shop and have no issues. I used the gray goop sealant instead of tape to seal the joints, and it works very well.

All the Best!


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## SASmith (Mar 22, 2010)

I used 4" sewer and drain PVC. Mine are not glued.


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## Manitario (Jul 4, 2010)

I agree with Randy; this topic has been debated on LJ's many times; a quick search will find you a diverse # of opinions.


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## Viking (Aug 26, 2009)

Jim;

Nothing wrong with PVC and larger is always better to reduce pressure (actually vacuum) drop in your piping. If you can make your main trunk line 6", even better. You can use 6" to 4" reducers at each tool / blastgate.

Use wyes instead of tee's and as little flex hose as possible. If you have adequate support there is no need to glue joints but, you should seal everything to prevent leaks. Not gluing joints also may give you flexibility in modifying your layout in the future.

Good luck!


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## donwilwol (May 16, 2011)

I've built mine over time and have both, and don't see how its different. I agree with not gluing. I change my layout and tools quit a bit, gluing would be a hassle.

You can read about this until your eyes bleed. My recommendation, just do it.


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## JollyGreen67 (Nov 1, 2010)

I'm new to this LJ thing, didn't really know what the "little" search bar was for - now I know! Plugged in my question there, and was swamped! Thanks for all the info. Question - is that metal stuff at Lowe's and Home Depot the HVAC stuff?


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## rance (Sep 30, 2009)

Yes, its the HVAC stuff. Or you can prob. get it cheaper at an HVAC dealer. With PVC, you might want to consider running a wire parallel to guard against static. With metal, you can get a sealer in a can to paint on. Metail might be easier to reconfigure if the need arises. Lots of questions and answers. Its just a choice. Do it!  No matter what you do, you'll think of "I should have…". Just do your best and adjust later if its too bad.


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## Elizabeth (Oct 17, 2009)

I used metal, and used self tapping screws and metal tape for installation. The tape was dead easy to use and even came off easily a couple of times when I realised I had to make minor alignment adjustments. Would have hated to try to do that with glued joints.


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## casual1carpenter (Aug 16, 2011)

Might want to web search billpentz or bill pentz. He has a lot of info on his site.


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## brtech (May 26, 2010)

Bigger is better only if you have the CFM. The "2HP" models typically don't.

PVC static is not a safety issue. Might annoy you some. There's lots written about it. Bottom line = not an issue.

Price out S&D PVC and "real" metal duct and see what you get. No 90 degree elbows - only 45s with a short straight section. No Ts, just wyes. Blast gates to close off what you don't use.

Most important thing is the filter. You need a .5 micron filter. Even the 1 micron really isn't enough, but its a lot better than a 5 micron.

The Thien baffle is a good investment - google it.

Ditto on the Bill Penz site. It will scare you, but it has A LOT of really good info.


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## DIYaholic (Jan 28, 2011)

I'm using 4" metal for my ducting. The main reason for my choice was that it was FREE!!! One of my favorite words. And when combined with my other favorite word BEER, I'm like a kid in a candy store!!!

IMHO, even though the screws only protrude a short distance in to the ducting, I feel they are a potential obstruction for chips to get caught on. So, I will NOT be using screws for connecting sections together. I plan on achoring the ducting securely to the wall &/or ceiling and use metal tape to secure and seal connections.


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## Sawkerf (Dec 31, 2009)

Since PVC, ABS, and heat duct are all smooth wall, the flow losses are minimal. It really depends on your budget.

I used 6" heating duct for my main trunk (~10') with reducers to 4" drops to the tools - except for the table saw. I cut the table saw cabinet to take a 4" x 14" x 6" diameter vent and tied that to the 6" main. All joints and seams were taped with the aluminum duct tape.

I also recommend using a cap at the end of your trunk. It's a great help if you need to clean the duct.


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## TheDane (May 15, 2008)

+1 for Bill Pentz ,,, http://www.billpentz.com/Woodworking/Cyclone/DCBasics.cfm ... lots of good info there.

-Gerry


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## JollyGreen67 (Nov 1, 2010)

After some thought, I'm going to stop at the Habitat for Humanity Restore place tomorrow and see what they have in the way of duct stuff. Competely forgot about them - get lots of stuff there I can't live without - might not be free - but it's cheeeep! Beer ? - as long as it's cold. Kinda partial to Sierra Nevada IPA.


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## IrreverentJack (Aug 13, 2010)

I read up on the static discharge issue with PVC pipe. The bad news is to ground a PVC pipe the metal ground wire needs to run along the inside of the pipe to a ground. The good news is that *wood chips and wood dust will not generate a static charge* at any speed close to what "our" size blowers will generate. Plastic particles might be another story. -Jack


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## a1Jim (Aug 9, 2008)

I've used 4" pvc for 25 years no problem .no glue just foll tape.


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