How do I seal NPT threads for Oil Sandwich?
#1
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How do I seal NPT threads for Oil Sandwich?
Hi everyone,
I just got an oil cooler sandwich adapter with 3/8 NPT inlet/outlet. I got 3/8 NPT to -AN 8 fittings. What is the best way to seal up the thread on the NPT? I heard Oil will eat away at Teflon tape.
Thanks for the help.
I just got an oil cooler sandwich adapter with 3/8 NPT inlet/outlet. I got 3/8 NPT to -AN 8 fittings. What is the best way to seal up the thread on the NPT? I heard Oil will eat away at Teflon tape.
Thanks for the help.
#2
Here's the jist of it. NPT is tapered pipe threads. They have slightly different tapers as to cause them to seal when they meet. The teflon serves as a lubricant to allow the fittings to get much tighter than they would without it. As you tighten the **** out of it, the two tappers meet each other and the metals deform, crush-sealing against one another. Once they crush 360* around the threads, you now have 100% metal to metal seal that won't ever leak. No seals to blow, no gaskets to leak or blow, no sealant to leak. It's metal to metal sealing.
#8
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tapered threads get the sealant, compression fittings dont need it.
and teflon should be ok with oil... UNLESS you get it in the oil path and clog your ****. that's the big problem. if you do use teflon tape, keep it away from the openings.
you can also get that goop you put on and let dry first. mcmaster probably has it.
and teflon should be ok with oil... UNLESS you get it in the oil path and clog your ****. that's the big problem. if you do use teflon tape, keep it away from the openings.
you can also get that goop you put on and let dry first. mcmaster probably has it.
#10
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This stuff works awesome.
THREAD SEALANT, TEFLON, HIGH TEMP - 034 MOTORSPORT
The rest of the chemicals they sell are also the best I have ever used.
THREAD SEALANT, TEFLON, HIGH TEMP - 034 MOTORSPORT
The rest of the chemicals they sell are also the best I have ever used.
#11
Regular NPT fittings actually won't fully seal if you don't use some sort of tape or sealent, there is a gap between the crast and root of the threads that creates a spiral leak path. An NPTF fitting on the other hand will fully seal.
National pipe thread - Wikipedia, the free encyclopedia
Swagelok SWAK works very well, and there isn't the same danger of a chunk of tape coming free from the inside of the seal and going through your system.
MS-PTS-6 - SWAK® Anaerobic Thread Sealant, 6 cm3 Tube
National pipe thread - Wikipedia, the free encyclopedia
Swagelok SWAK works very well, and there isn't the same danger of a chunk of tape coming free from the inside of the seal and going through your system.
MS-PTS-6 - SWAK® Anaerobic Thread Sealant, 6 cm3 Tube
#12
Regular NPT fittings actually won't fully seal if you don't use some sort of tape or sealent, there is a gap between the crast and root of the threads that creates a spiral leak path. An NPTF fitting on the other hand will fully seal.
National pipe thread - Wikipedia, the free encyclopedia
Swagelok SWAK works very well, and there isn't the same danger of a chunk of tape coming free from the inside of the seal and going through your system.
MS-PTS-6 - SWAK® Anaerobic Thread Sealant, 6 cm3 Tube
National pipe thread - Wikipedia, the free encyclopedia
Swagelok SWAK works very well, and there isn't the same danger of a chunk of tape coming free from the inside of the seal and going through your system.
MS-PTS-6 - SWAK® Anaerobic Thread Sealant, 6 cm3 Tube
#14
The Vast majority or "NPT" parts sold now are actually NPTF, and if any of the fittings are copper or brass or anything soft you can generally get a seal on either one, but if you are dealing with an actual NPT port and the port and fittings are steel you won't get a perfect seal. It's probably not really an issue in most automotive applications; my experience with it comes from high pressure (5000psi+) natural gas work. I'm just saying an NPT fitting was never designed to fully seal without some soft of sealant. If you are sticking an NPT fitting into the side of your engine, why not give it the best chance of sealing and stick some sealant on it. If it does nothing else, it will reduce the friction and galling letting you get the fitting in tighter for a given torque on it.
#15
I agree with you, the problem is most people don't know how to use the "sealants" properly. especialy teflon tape. which I reserve only for steel threads. I think most people would be better served getting a good seal in automotive applications by using new fittings and actualy running them in far enough to make a good seal rather than gooping on "sealant" or wrapping them with twenty turns of tape in the wrong direction.
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