Looking for “Black pipe dope” advice………...

[Sidekick]

I read don't use synthetic oil in your compressor if you use pex. The vapors that make it through the pump can destroy pex over time. I worked with a guy that used pvc for his compressor lines and didn't have a problem until trying to sell his house. Banned by code and all had to be removed.

 

[chim]

Our mechanical division we had an "incident" while testing PVC piping with air pressure - as required by the specs. I don't recall the size, except I think it was larger than 2" and received lots of attention. Fortunately, there were no injuries. The company VP decreed there would never be any air tests on PVC again, regardless of the specs.

 

[weaponoffreedom]

Chinese NPT threads are terrible...I use teflon tape and a paste type dope. Gasiola, Resctorseal, and Blue Monster are all good brands.

The above is correct....I will add:

Teflon tape can act as a "shim" of sorts when threads are not exactly to NPT specs. For air, especially with systems that vibrate a lot, the blue paste type works very well, with or without tape. PTFE and teflon is a lube, the threads is what make the seal.....just an FYI

NC licensed Plumber here.

Rectorseal 31300 Quart Brush Top Tru-Blu Pipe Thread Sealant , Blue: Hardware Sealers: Amazon.com: Industrial & Scientific

 

[PoTreeBoy]

Our mechanical division we had an "incident" while testing PVC piping with air pressure - as required by the specs. I don't recall the size, except I think it was larger than 2" and received lots of attention. Fortunately, there were no injuries. The company VP decreed there would never be any air tests on PVC again, regardless of the specs.

I'm curious what service required pneumatic testing. The only one I can think of would be sewer, which would be under low pressure.

In my years of petrochem, folks got real excited (in a negative way) when pneumatic testing was brought up.

 

[PoTreeBoy]

The subject of this thread is air, but if your natural gas pipe dope has to pass an inspector, it better be yellow in many jurisdictions.

 

[weaponoffreedom]

The subject of this thread is air, but if your natural gas pipe dope has to pass an inspector, it better be yellow in many jurisdictions.

Correct, but also incorrect, by the inspector. There is nothing that prohibits the use of any other color tape.....technically, you are not supposed to use both dope and tape, per manufacture. Yellow tape on other than NG or LP is prohibited.....weird

 

[North Idaho Wolfman]

Correct, but also incorrect, by the inspector. There is nothing that prohibits the use of any other color tape.....technically, you are not supposed to use both dope and tape, per manufacture. Yellow tape on other than NG or LP is prohibited.....weird

I've switched all of my teflon tape use to fastape.

 

[chim]

I'm curious what service required pneumatic testing. The only one I can think of would be sewer, which would be under low pressure.

In my years of petrochem, folks got real excited (in a negative way) when pneumatic testing was brought up.

I believe it may have been chilled water for HVAC (because we normally tried to avoid plumbing jobs). The project was at the State Farm Show Building. I texted a bud to see if he remembers.

With your background you probably recognize something we had a chance to play with:

 

[North Idaho Wolfman]

I'm curious what service required pneumatic testing. The only one I can think of would be sewer, which would be under low pressure.

In my years of petrochem, folks got real excited (in a negative way) when pneumatic testing was brought up.

When I worked in Production facilities they often used schedule 80 PVC for chemicals or cool / chilled water / coolant delivery.
I was on more than one job that has a pop / boom from it failing.

Intel used a stainless pipe inside a clear PVC pipe for boron delivery as it's highly toxic in even the smallest amounts. the second pipe was a containment and counter acting chemical to neutralize the boron.

 

[North Idaho Wolfman]

I believe it may have been chilled water for HVAC (because we normally tried to avoid plumbing jobs). The project was at the State Farm Show Building. I texted a bud to see if he remembers.

With your background you probably recognize something we had a chance to play with:

View attachment 164689

I'm getting the pig...
Name that movie!

 

[North Idaho Wolfman]

When I built my house the sewer lines, the Hydronic heat lines, the Gas lines and the water lines all were under test for an extended period of time, and all the while while the concrete was being poured and finished and then throughout the build till landed at location.
Didn't want even the slightest leak under the 6" to 24" of concrete.

 

[chim]

I'm getting the pig...
Name that movie!

Ding ding - you win Name That Tool

Can't name the movie

 

[North Idaho Wolfman]

Ding ding - you win Name That Tool

Can't name the movie

RED

 

[PoTreeBoy]

I believe it may have been chilled water for HVAC (because we normally tried to avoid plumbing jobs). The project was at the State Farm Show Building. I texted a bud to see if he remembers.

With your background you probably recognize something we had a chance to play with:

View attachment 164689

I had an ugly, amusing now, encounter with one of those things early in my career.

 

[Runs With Scissors]

Thanks for all the replies guys!

It appears that “Rectumseal" has the market pretty well cornered on sealing solutions.

I decided to try the “Tru-Blu" …….However when I went to Menards, I did’t have my glasses with me and I accidentally picked up some "Blue +"

They must have been either next to each other and I grabbed the wrong one, or it was in the wrong spot.

Either way, when I got home, I noticed it and did not feel like going back, and when I looked it up, it appears that “Blue +” is the same thing as “Tru-Blu” but with some sort of “synthetic fibers” in it.

So instead of going back I tried it.

I “re-did” my original set up and tested it…………….. So far, so good

Thanks again.