# Smoke Test Results: PVC-PVC Fittings Don't Need To Be Sealed (so it seems?)



## keith204 (Nov 24, 2009)

Dare I be so bold as to assert something such contrary to common belief? It appears that aluminum tape is only for security, peace-of-mind and bling. (all of which are important)

But as far as air leakage is concerned, I feel my tests exceed practical reasoning. *Tests include:*

Negative pressure test: Localized smoke placed near each unsealed joint (tested around 30).
Positive pressure test: Lines primed, sealed off, and additional smoke pushed in (low pressure)
Positive pressure test: Lines primed, sealed off, then pressurized with an air compressor

The amount of pressure buildup was limited due to an issue with one of my blast gates, but it was enough to expose an issue with a tiny PVC-BlastGate connection leak on the other side of the garage. I feel that a pressure test is a bit ridiculous anyway, as it may actually push joints apart. 

A more powerful dust collector may reveal different results. Mine is a 2HP Grizzly w/ a pleated filter. 

*VERDICT*: I *will* seal my joints with aluminum tape for security and peace of mind (and bling). It's cheap, easy, and I'm tired of bumping things apart each time I modify something.

For reference, here's the full video including my story as it led me to these tests, then the tests (at least some), my concerns/caveats with the tests, and a smoker build. 






I would be a fool to think that my tests covered all the bases and decided this one-and-for-all. If you found that PVC-PVC _does_ need to be sealed, I'm interested to hear more about your setup.


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## sunnybob (Sep 3, 2016)

I've used PVC and metal, the only air leaks I have ever found are on the blast gate slides.
I have used ali tape on 4" metal joints, but more to stop the joint coming apart from vibration rather then to stop an air leak.


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## GeorgeC (Jul 30, 2008)

Any air leak that you get is going to so be minor as to be meaningless. Unless you have very ill fitting joints.



George


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## Catpower (Jan 11, 2016)

Wipe the joint with PVC cleaner or lacquer thinner before assembly and insert while it is still wet. It will stick until you disassemble it but you will probably need a hammer and some persuasion to take it apart


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