I read somewhere that npt seal by the tapered cone shape. The thread crush together to make the seal. I ordered some npt fittings and just wondering do I need to get some Teflon tape too or no?
Does npt threads need Teflon tape?
- Thread starter ImpactX
- Start date
Yes, keep the Teflon 2 threads from end as to avoid pushing any “tape” into “plumbing” system. Teflon acts as a “lubricant” for the most part.
Upvote 0
Also I recommend using the yellow Teflon tape over standard white. I have had much better experience with with it. Its thicker than standard white and seals better under heavy pressure.
Upvote 0
Depends,, do you want it to seal high pressure air? get the tape! some will tell ya to get the yellow for natural gas or the expensive black,, there is a right direction and there is a wrong direction to wrap the tape, also 2 full wraps, not less, not more, the guy in this vid over does it with too many wraps
https://www.youtube.com/watch?v=j5jYLvNsK94
https://www.google.com/search?q=yellow+tape+for+gas&oq=yellow+tape+for+gas&aqs=chrome..69i57.8960j0j4&sourceid=chrome&ie=UTF-8
Edit: sorry Raden, I was typing and linking as you posted faster than I ,, I agree, the yellow is better,, my comment was not to put you down
https://www.youtube.com/watch?v=j5jYLvNsK94
https://www.google.com/search?q=yellow+tape+for+gas&oq=yellow+tape+for+gas&aqs=chrome..69i57.8960j0j4&sourceid=chrome&ie=UTF-8
Edit: sorry Raden, I was typing and linking as you posted faster than I ,, I agree, the yellow is better,, my comment was not to put you down
Upvote 0
the threads 'do' crush together and thats what makes the seal, true, but as said above the tape is a lubricant to allow it to be twisted tighter .. ive had a rough time getting an absolute seal using tape, in other words a seal that will hold air without losing any with pressure left on as in an external reg application etc .. what works is loctite 545 and no tape, but it needs to be applied liberally and allowed to cure for a week 10 days to hold hpa .. but tape is fine on a fill setup where alittle seepage is inconsequential ..
Upvote 0
Word of warning- if these NPT fittings aren’t PARKER or a quality fitting like PARKER fittings, but ones made overseas, you can easily split them by over tightening. I say over tightening but it wouldn’t have been over tightening with a Parker fitting. Talking from experience. I barely had two full turns in and I put a hairline split that was undetected till I went to use it and had a leak.
Upvote 0
Never in aluminum. The taper along with the reduced friction from the tape will split the aluminum if over tightened.
Tighten NPT threads just enough to seal.
Tighten NPT threads just enough to seal.
Upvote 0
Coming from a plumbing background (LU230, San Diego, CA), if you're connecting pipe/fittings for a low-pressure air system (or water), then yes, use the yellow Teflon tape that is made for natural gas piping. Natural gas piping is normally malleable fittings with steel pipe using the NPT threads, which are tapered as mentioned. They don't really crush together, they simply form a seal via the taper. This might be for .5" > sizes.
If you're using pipe/fittings for high-pressure air, there could be an issue using the yellow Teflon, which maybe sufficient. The reasoning is that MOST Teflon tapes are manufactured with an oil based product So to be on the safe side, I use a product called Formula 8 (a paste), which is made specifically for Medical Oxygen piping in hospitals and is safe to use for any threads due to being inert. There is also a specific Medical Gas Teflon tape that I use that is not an oil base product, so is as safe as the paste. I only use these on high pressure connections.
My 2¢ anyway.
mike
If you're using pipe/fittings for high-pressure air, there could be an issue using the yellow Teflon, which maybe sufficient. The reasoning is that MOST Teflon tapes are manufactured with an oil based product So to be on the safe side, I use a product called Formula 8 (a paste), which is made specifically for Medical Oxygen piping in hospitals and is safe to use for any threads due to being inert. There is also a specific Medical Gas Teflon tape that I use that is not an oil base product, so is as safe as the paste. I only use these on high pressure connections.
My 2¢ anyway.
mike
Upvote 0
Ok thanks guys. I thought npt thread didn't need Teflon tape cause they are tapered. thought only bsp and m10x1 needs it. Will get some Teflon tape too.
Upvote 0
M10 and BSP fittings don’t get Teflon tape. They are usually sealed by a plastic tiny square cut doughnut ring seal like what came inside your lightning parts bag, or metal rubber seals called Dowty seals
@ Union brother Revoman- great advice to post up on an open forum. I’m out of LU 104 Bay Area/Sacramento. Be good, buddy
Upvote 0
Unless the fitting has a plastic washer or a Dowty seal under it you will need teflon tape, the paste mentioned or locktight to seal it.
I have often used the blue locktight and have never needed heat to make it release.
I have often used the blue locktight and have never needed heat to make it release.
Upvote 0
NO...NPT threads do NOT NEED Teflon tape !
I normally use oil (engine oil !) on ALL of my NPT threads. Be them brass, aluminum, steel or stainless steel. I've NEVER used Teflon tape on ANY of my NPT threaded joints. I've worked on cars, motorcycles, boats since I was around 14 or 15. I'm 71 right now !
Funny thing, even most plumbers don't even use that crap. They use Teflon paste. Unless you are perfect at applying it, it gets into everything. I can't tell you how many people that I've helped with their engine oiling problems and their fuel system problems...only to find...Teflon tape where it should NOT be.
If you feel that you can't make this connection correctly with out help, use Teflon..."PASTE". MUCH better at lubricating, MUCH better at sealing.
Your toys, your money, Use whatever you see fit, if you'd like to stop by my house for a demonstration, I can show you why the tape is crap.
Mike
I normally use oil (engine oil !) on ALL of my NPT threads. Be them brass, aluminum, steel or stainless steel. I've NEVER used Teflon tape on ANY of my NPT threaded joints. I've worked on cars, motorcycles, boats since I was around 14 or 15. I'm 71 right now !
Funny thing, even most plumbers don't even use that crap. They use Teflon paste. Unless you are perfect at applying it, it gets into everything. I can't tell you how many people that I've helped with their engine oiling problems and their fuel system problems...only to find...Teflon tape where it should NOT be.
If you feel that you can't make this connection correctly with out help, use Teflon..."PASTE". MUCH better at lubricating, MUCH better at sealing.
Your toys, your money, Use whatever you see fit, if you'd like to stop by my house for a demonstration, I can show you why the tape is crap.
Mike
Upvote 0
Odd to see NPT fittings, In the Airgun world we've become accustomed to BSPP (British standard parallel pipe).
Upvote 0
"NO…NPT threads do NOT NEED Teflon tape !"
While this may be a good idea for oil, it's not for gasoline, or clean systems that cannot have any oil. Teflon tape is a very valid means of creating a solid, leak-proof connection. As I also stated, I use paste for high-pressure air lines where oil is bad juju, but will also use the RIGHT Teflon tape when needed.
It is completely dependent upon the material being conveyed. A blanket statement is not justified. To each their own.
Bigragu....I KNEW that you would appreciate the affiliation!
mike
While this may be a good idea for oil, it's not for gasoline, or clean systems that cannot have any oil. Teflon tape is a very valid means of creating a solid, leak-proof connection. As I also stated, I use paste for high-pressure air lines where oil is bad juju, but will also use the RIGHT Teflon tape when needed.
It is completely dependent upon the material being conveyed. A blanket statement is not justified. To each their own.
Bigragu....I KNEW that you would appreciate the affiliation!
mike
Upvote 0
Those are kind of expensive to buy ready made. $37.50
Yep that is exactly what I'm making. There are 3 parts, each cost about $8-10 each. So total is about $30. All stainless steel so I'm pretty sure it will handle 4500 psi fill to my tank/guns.
Upvote 0