Sealing PVC DC Ducting

[Ken Krawford]

I've had my cyclone DC for a number of years and never sealed the PVC duct connections. My initial thought was "let's see if this works ok" before doing anything more permanent. I'd really like to avoid PVC cement if possible so when I move, I can reuse the ducts with a minimum of effort.
I know that plain old duct tape is a very poor choice.
It appears aluminum tape is a much better choice but I know from experience it is nearly impossible to remove from a pipe once it is applied.
I'm curious what people have used to seal their PVC ducts.

[Robert Delhommer Sr]

Nothing, mine is still unsealed. I feel the leakage is negligible.

[Bob Falk]

I used a flexible, but removable, caulking used for weather sealing windows. Bought it at a big box store. Was dust proof, but peeled right off when I wanted to change a fitting.

[Larry Frank]

you can use a white duct tape or better yet use nothing. When I have taken monetary the joints are sealed with fine dust...self sealing.

[Michael Stein]

Just out of curiosity, but why is Duct Tape a poor choice? Thats what I used to seal mine (albeit, I have a very small DC setup) and it has worked fine so far, I used the black variety, as thats what I had on hand.

Mine is also a relatively new setup, so if it is a bad choice, then it would be in my best interest to change now.

Thanks.

[glenn bradley]

I've used nothing at the main joints. I found some leakage where the 7" steps to the first 6" ASTM-2729. I used some silicon tape there. All other seams show no leakage with just the slip-fit except the blast gates. I did silicone the blast-gate connections as they were less than perfect. This is easily removable from PVC.

[Brian Tymchak]

I used Xtreme tape (http://www.rockler.com/x-treme-tape-for-dust-joints) for some joints when I reset a duct for a new MS bench. Seems to work pretty well but I haven't used the MS much since I built the bench. It is a bit pricey and will lose it's effectiveness to grip to itself if applied/reapplied several times.

[Jesse Busenitz]

The PVC I used was gasketed so I'm guessing it's not leaking much if at all. A few of the fittings were glue joints but I just made sure they were a tight fit and if not, put a little silicone on.

[Larry Browning]

I've used silicone caulk with great success. It goes on easy and will peel off when needed.

[roger wiegand]

Duct tape is both good and easy to use. You need to go to the plumbing section of the store and find the ASTM-rated tape (ASTM D5486 I think) that is actually made for sealing ducts. It costs 5-10x more than the common stuff, but is quite strong and lasts a long time. I moved my system after 10 years of use and the duct tape I took off was pretty much indistinguishable from new, so it's lifetime is easily a couple decades. Much less of a mess than silicone caulk, which I also tried.

[Keith Outten]

PVC pipe fittings are self sealing generally speaking as long as the joint is tight. I drill and install three small screws in each joint to make sure the joint remains tight. The screws are easily removed and the pipe and fittings can be removed or reconfigured at any time.

[Robert Engel]

I agree re: leakage not a big deal.
I used duct tape.

[Steve Peterson]

Just out of curiosity, but why is Duct Tape a poor choice? Thats what I used to seal mine (albeit, I have a very small DC setup) and it has worked fine so far, I used the black variety, as thats what I had on hand.

Mine is also a relatively new setup, so if it is a bad choice, then it would be in my best interest to change now.

Thanks.

The cheap rolls of gray duct tape will disintegrate within a year or two if used in a hot attic. It also fails if exposed to UV light. However, it may last nearly forever in a basement environment. I wouldn't bother changing anything unless you see it starting to peel back.

There are other brands of tape designed to seal ducts. Foil tape is probably the best option. It sells for around $10 per roll. Gorilla tape or other high end brands might also do quite nicely. They have some really strong adhesive.

My system has no sealing. I started putting screws, but then never even bothered with them unless the pipe was hanging. Most sections are naturally held together and there is no way for them to fall apart.

Steve

[Chris Padilla]

As others have said, I use a small length screw or two to keep the joint together and then smear some silicone around the outside and call it good. They come apart relatively easily.

[Bruce Wrenn]

Nothing but friction for joints. For blast gates, I swedge them on. No screws or clamps. They aren't going anywhere. At least they haven't since 2003.

[Chris Padilla]

I have a feeling 2016 could be the year, Bruce! LOL! ;)

[Garth Almgren]

I used foil tape from Harbor Freight. $6.99 a roll, or less if you get it on sale or with a coupon.

[Alan Schaffter]

You really don't need to seal the joints, but if you want to be sure, just use a very small bead of silicone caulk (NOT Latex) on the OUTSIDE of the joint after assembly. Remember the duct is under negative pressure so the seal is tighter when the DC is running. Silicone rubs off PVC easily with a finger (Latex caulk does NOT). Cheap duct tape falls apart in a few years and leaves a residue of hardened adhesive that is hard to remove.

[Chris Damm]

I just started to remove my DC piping as we are ready to move south. It has been in place for about10 years and is made of mostly 6" PVC sewer pipe. I sealed the joints with foil tape from Ace Hardware. It comes off quite easily with a little tearing. It is a little harder to remove from the metal ductwork but that's why they make razor knives.

[Ken Krawford]

Thank everyone for the replies. I must have gotten some cheap duct tape because I used it as a test on one joint and just as Alan noted, it disintegrated and left an adhesive residue on the pipe. I considered foil tape but every time I've used it, I had a lot of trouble removing it. Maybe on PCV it's different. I may give Silicone a try.