Connecting 1/2" NPTF

[Oldtoad]

Got some hydraulic hoses in the mail with fittings.
Is there goo needed? Just crank 'em down?
Teflon tape can get into the system so care has to be taken with that.

 

[Roadworthy]

NPT is generally tapered to ensure leak prevention. A small amount of thread tape will smooth the tightening of the fittings. Of course you could use "goo" to help by lubricating and sealing the threads.

 

[lpakiz]

I will catch some flack over this, but I never use tape. Too much chance of a bit coming loose and causing problems.
I only use the Teflon "dope" that comes in a tube and is available in most every big-box store.

 

[Farmer495]

I've used tape...but VERY careful with it making sure it is uniform and a thread or two from the end of the fitting is exposed to prevent tape from coming off into the line.

 

[the old grind]

'Dopes/tapes' are lubes to allow tightening tapered threads to an interference fit. They are not meant to be stand-alone sealants.

My choice for NPT hydro lines is Permatex #2 non-hardening. It is fuel-proof & approved for high temps and steam fittings. Anything that leaks/weeps wasn't tightened enough.

 

[Root Cause]

+1 on dope

 

[lpakiz]

To add a bit more to my "no tape" policy, most times, with careful application of tape, the first assembly is just fine.
It is the subsequent disassembly and reassembly that pushes used tape ahead of the male part and into the oil-stream.

 

[WranglerX]

Use this on water, fuel, oils, and anything with tapered threads...

 

[etpm]

Got some hydraulic hoses in the mail with fittings.
Is there goo needed? Just crank 'em down?
Teflon tape can get into the system so care has to be taken with that.

NPTF is made to be used without any type of lube or sealant. It is also known as Dryseal. The thread has sharp crests that bite into the mating fitting which helps with the sealing. So thread goo isn't needed. If you later take it apart you may find that the thread is galled badly.
Eric

 

[LouNY]

And to really kick off the discussion teflon tape is not a sealant it is a thread lubricant.
A good thread lubricant will allow NPT threads to distort and seal with no damage,
so they can be broken apart and reassembled without leaks.