PVC vs Metal DC ducting

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Forum topic by JollyGreen67 posted 01-04-2012 10:31 PM 3634 views 0 times favorited 16 replies Add to Favorites Watch
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1676 posts in 3000 days

01-04-2012 10:31 PM

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.

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected ! RIP 09/08/2018

16 replies so far

View jusfine's profile


2422 posts in 3163 days

#1 posted 01-04-2012 10:37 PM

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!

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View SASmith               's profile


1850 posts in 3224 days

#2 posted 01-04-2012 10:37 PM

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

-- Scott Smith, Southern Illinois

View Manitario's profile


2703 posts in 3120 days

#3 posted 01-04-2012 10:42 PM

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

-- Sometimes the creative process requires foul language. -- Charles Neil

View Viking's profile


880 posts in 3433 days

#4 posted 01-04-2012 10:51 PM


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!

-- Rick Gustafson - Lost Creek Ranch - Colorado County, Texas

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Don W

19045 posts in 2805 days

#5 posted 01-04-2012 10:59 PM

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.

-- - Collecting is an investment in the past, and the future.

View JollyGreen67's profile


1676 posts in 3000 days

#6 posted 01-04-2012 11:08 PM

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?

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected ! RIP 09/08/2018

View rance's profile


4267 posts in 3398 days

#7 posted 01-04-2012 11:24 PM

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.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View Elizabeth's profile


817 posts in 3381 days

#8 posted 01-05-2012 12:05 AM

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.

View casual1carpenter's profile


354 posts in 2713 days

#9 posted 01-05-2012 12:25 AM

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

View brtech's profile


1054 posts in 3160 days

#10 posted 01-05-2012 12:34 AM

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.

View DIYaholic's profile


19741 posts in 2912 days

#11 posted 01-05-2012 12:41 AM

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.

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View Sawkerf's profile


1730 posts in 3306 days

#12 posted 01-05-2012 12:48 AM

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.

-- Adversity doesn't build reveals it.

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5575 posts in 3900 days

#13 posted 01-05-2012 01:04 AM

+1 for Bill Pentz ,,, ... lots of good info there.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View JollyGreen67's profile


1676 posts in 3000 days

#14 posted 01-05-2012 04:19 AM

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.

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected ! RIP 09/08/2018

View IrreverentJack's profile


727 posts in 3080 days

#15 posted 01-05-2012 06:28 AM

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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