Securing and sealing snap-lock ducting

Bela, I built my duct system out of the 26 ga. snap lock and then sealed all of the joints and seams with aluminum duct tape. It does a great job of sealing and is very malleable when going around curves.

I did all of the seams on the 5’ duct runs and on the blast gate connections also. I am very pleased with the system and have no major leaks. I even wrapped the edges of the blast gates.

Randy

-- Randy, Central MN

Thanks Randy, nice installation! – Did you find need to screw or rivet the connections or did the tape make things secure enough?

-- Béla, Memphis TN

I used foil tape, lots of it (!) on the seams and joints and then turned the system on from time to time to feel for leaks, none found. There was one Y fitting that had a leak in the weld, I added silicone there. No screws.

The only place I used sheet metal screws was where i installed blast gates.

-- Randy, Central MN

I used short pop rivets, and taped every joint with aluminum tape. Just don’t use duct tape, it will not last. That is a nice looking setup, you have there.

-- Bob in Montana. Kindness is the Language the blind can see and deaf can hear. - Mark Twain

This is a few years old, but I’d like to hear what people have been doing lately with their installs. Has anyone used sheet metal screws or is the consensus to just use tape on every joint? How about a metal blast gate? Same there or pre-drill, install screws and then seal with caulk? I’ve bought pretty much everything I need for my install and would appreciate some insight on proper connections.

I used self-tapping sheet metal screws to assemble 26 gauge spiral pipe and it works well. I could even drive them right into the aluminum blast gates.

Tape is still needed afterwards to seal air leaks but the screws prevent the pipe from sagging and ripping the tape.

Avoid caulk on joints as it’ll make life difficult if you decide to make changes down the road. Caulk on the seams of the snap-loc may be a good idea or you can just tape that off too.

-- See my work at http://altaredesign.com

I am a retired sheet metal worker and I have installed miles of snap lock duct. Two years ago, I put in a six inch 26 Gauge system in my shop using sheet metal screws at the joints but not along the seams. I sealed all the seams and joints with a brush on sealer. Worked well for me.

-- No PHD just a DD214 Lubbock Texas

I used self-tapping sheet metal screws to assemble 26 gauge spiral pipe and it works well. I could even drive them right into the aluminum blast gates.

Tape is still needed afterwards to seal air leaks but the screws prevent the pipe from sagging and ripping the tape.

Avoid caulk on joints as it ll make life difficult if you decide to make changes down the road. Caulk on the seams of the snap-loc may be a good idea or you can just tape that off too.

- JAAune

That makes a lot of sense. No need for the long run of pipes to sag. I was reading through some of the earlier comments about air restriction with all the screws going in and maybe some scraps possibly catching onto the screws, which is why I’m asking. I see the rivets being a good option, but you can’t separate them very easily if something happens or you decide there might be a more efficient design or maybe you bought a shiny new tool that needs the system modified. I do see that people aren’t particularly fond of using caulk on the blast gates, so how do you seal these? Does the tape work pretty well?

Pop rivets can be drilled out easily. Spiral pipe leaks badly. I have seen this while doing smoke/leak tests. Long seam to seal there. This is why I used snap lock pipe.

-- No PHD just a DD214 Lubbock Texas

I sealed my 26 gauge snap duct and fittings with the grey goop stuff. Initially, used duct tape to seal the seam itself and then grey goop (can not remember the true HVAC name) over everything. Very easy to remove if needed.

-- The Carpenter Bee is derived from the Ancient Greek word wood-cutter "xylokopos/ξυλοκὀπος"