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Sandy Dukeshire
05-01-2012, 04:24 PM
after long (l-o-n-g) last, i am hooking up my oxy propane hand torch and have heard conflicting opinions on the use of thread tape for brass fittings. the welding guy insists no tape needed - "its brass". others have said dont even think of not using tape. in the past i have used teflon tape on most applications. if its "not really" needed, can i use it anyway just to make me feel better without damage?

Pete VanderLaan
05-01-2012, 04:30 PM
It should work either way Sandy. Just soap the fitting when you have finished and check for leaks.

George Tessman
05-01-2012, 04:31 PM
brass or not...the real key is if it is a compression fitting or npt fitting...if you use tape on a compression fitting. it may not seat all the way...

Thomas Chapman
05-01-2012, 05:22 PM
Right--that is the distinction. Tape for NPF, not for compression fittings.

Pete VanderLaan
05-01-2012, 06:03 PM
That's NPT.

Doug Sheridan
05-01-2012, 07:17 PM
I was taught that tape or pipe dope on brass will cause it to crack from turning too far on the threads, beyond what would be needed to prevent it from leaking. Brass is not steel and does crack under pressure, no matter what kind of connection.

Kier Lugo
05-01-2012, 09:11 PM
At the school i work at we also do a lot of fire effects and some off site demos where we use a lot of brass fittings. it is my understanding that if it is a brass on brass threaded connection then in theory you do not need to use the tape because the brass is soft and it is supposed to fit together snugly. if you are threading brass and some other metal together then you would want tape. having said that we often will tape brass on brass threaded connections. as long as you don't over tape and make sure you wrap the tape in the correct direction i don't think it will be a problem. also there is a yellow (thicker) teflon tape that is specifically designed for gas fittings. this would be better to use than the white plumbing tape. just make sure you soap test for leaks. that is the main goal.

Richard Huntrods
05-01-2012, 09:50 PM
The pipe fitter who did my propane setup used the yellow "gas" type of tape on NPT fittings. The inspector who inspected the work made me redo one fitting that I had done because he could not see the tape on the finished joint. Once I re-did it with yellow tape so there was a bit sticking out (about 1mm) he passed the whole system.

The yellow tape is specificallly made to seal gas joints in NPT fitting and is used instead of the pipe dope for convenience. Both are (I was told by the inspector) to code here.

-R

Rick Sherbert
05-02-2012, 08:28 AM
On "B" fittings (welding hose, torch conncetions, etc.) there is a cone in the female end and an identical seat in the male end. The cone sets tight in the seat and seals the system. The gas shouldn't even get to the threads. If it does, no amount of tape is going to stop a leak because the female nut swivels around the fitting so you can thread it on and there is no way to seal that up with tape. Same with flare fittings, same with compression fittings. Tape needed on pipe thread only.

Mike Hanson
05-02-2012, 11:52 AM
NO tape Sandy.

Just check your connections with a soap solution in a spray bottle and look for bubbles .

Sandy Dukeshire
05-02-2012, 03:29 PM
i'm going with the no tape route and yes yes yes..will do duh soap test.
thank you ALL for all the feedback.
time to fire away baby!

Rich Tuttle
05-02-2012, 05:37 PM
Somewhere I learned that soap should NOT be used to test for O2 leaks. Apparently materials you might not expect to be flammable become flammable when in an O2 rich environment. Some soaps have oils in them. Maybe this is overly cautious but thought it was worth mentioning for brighter minds to pick apart.

Pete VanderLaan
05-02-2012, 06:30 PM
WHile I have heard that there are better solutions for leak testing, I have been at this forty years and done it with gas inspectors all that time. Soap works great. This subject is certainly getting beaten to death.

George Tessman
05-02-2012, 08:46 PM
lets beat the dead horse some more...as most know i work for the power company. Not only do they supply the electric but, they also do the natural gas. Since the influx of overseas pipe. They know have a policy to not only use tape, but pipe dope as well. This is due to the inconsistency of the pipes

Pete VanderLaan
05-02-2012, 09:11 PM
well, OK if they were real brass fittings, they wouldn't need pipe dope or tape but they're those fake fittings i am well familiar with. I don't like to buy chinese fittings actually. You can see and feel the difference.

C'mon man shoot the horse would you?

Rick Sherbert
05-03-2012, 08:11 AM
<sound of slide racking> BANG!

Eben Horton
05-03-2012, 08:44 AM
Only use metric tape.

George Tessman
05-03-2012, 01:23 PM
sorry should of added...this is the black gas pipe...i know off topic a little. but, it is out there

Rick Sherbert
05-03-2012, 04:18 PM
Horse still moving.... reloading....

Charles Friedman
05-05-2012, 12:48 AM
Ivory soap is the soap of choice, it does no harm to fittings or hose material.

BANG!