Pipe dope for brass gas line connections?

[Super51]

Have to agree with 504 on GASOIL thread sealant,it is gas resistant,have used it on Super-C where shut off valve and bowl screw into bottom of tank,never has leaked a drop!Even use it on compression fitting nuts as a backup just in case!
 

[Eric Dahlstrom]

Generally speaking, the condition of the thread or the mating surfaces is most important... If it's a flanged connection, using some PTFE dope on the threads, only provides some lubrication, so that the connection can be properly torqued. If it's a pipe thread connection, the threads are the mating surfaces, and their good condition, and cleanliness is essential... A good PTFE, like Gasoila, will do the job well... Again, it's primary purpose is lubrication, allowing for a proper torque to be applied to seal the threads.
 

[showcrop]

[Greenfrog]

I'll add to my own question and to the discussion here....
An old time plumber always told me that pipe dope was used to no only seal, but to allow it to come loose more easily in the event that one should have to take it apart...especially in galvanized pipe.
I also have read that some plumbers use both--tape and dope.
Anyway, good discussion here....good common interest....thx for all the input
 

[WGM]

He sure is. Tape is nothing but crap made for use by pretend plumbers/fitters. There has been plenty of good products mentioned here by others. Use one of them. Tape is not one of them.
 

[Eric Dahlstrom]

Your question must be rhetorical... The answer is... No, plumbers don't use torque wrenches, their work is done mostly by feel, though, there is a rule of thumb, hand tighten plus two full turns.

There are a couple of types of fittings that we could be dealing with; Flared fittings, used in both hydraulic fittings and fuel systems. And, tapered NPT fittings...

I think for the most part, we'd see flared fittings in the fuel systems. In either case, using tape is discouraged, because there is a chance for pieces of tape to to migrate into systems and cause problems. But, in a flared connection, the condition of the flared mated surfaces is most important. Having a lubricant on the threads will ensure that it can be tightened properly. Torque, is an acceptable term to use... As it's a rotation force.

Tapered NPT fittings are a interference fit, where if they are machined perfectly, and lubricated, and tightened, it is theoretically possible for them them to form a hydraulic seal. But, since manufacturing techniques are knocking out thousands of parts in a run, tolerances can't be kept close enough to achieve that kind of result.

I personally like a paste, because it has the ability flow better, and seal imperfections in materials. But, again make sure everything is very clean.
 

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[Eric Dahlstrom]

I'll agree to your point, on the interference fit... I'm certain that I misapplied the term.

I agree, too, on the point of lubricating the flared fittings.

So, overall, I think we're in agreement.
 

[pat sublett]

If you use Teflon tape on gas or oil, make sure it is yellow, that said I personally don't use Teflon tape. I have problems with it leaking 2 or 3 years down the road. I use rector seal on everything that needs sealer which is tapered pipe treads only.
 

[jtwat]

I read somewhere long ago that Teflon Tape is not a sealant but adds lubrication to threads so they can be tightened. I only use a liquid sealant on threads. Been using Blue Monster from Lowes. Works well.
 

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[1948CaseVAI]

http://www.gasoila.com/