lejones1445
Member
Anyone know of a source for a 3/8" npsm cap? I have my pressure pot all set to go but I can't find a cap to seal off my Harbor Freight pot.
Can't find npsm cap for pressure pot
- Thread starter lejones1445
- Start date
Signed-In Members Don't See This Ad
Signed-In Members Don't See This Ad
BSea
Member
Here's 1 maybe: Anderson Metals 56108 Brass Pipe Fitting, Cap, 3/8" NPT Female Pipe: Industrial Pipe Fittings: Amazon.com: Industrial & Scientific
I don't know the difference between npsm and npt, or if they are compatible.
I don't know the difference between npsm and npt, or if they are compatible.
Monty
Group Buy Coordinator
Don't know what a npsm cap is.
The Penguin
Member
NPT?
Any hardware store (Ace, HD, Lowes) should have a decent selection of brass fittings in their plumbing department.
Any hardware store (Ace, HD, Lowes) should have a decent selection of brass fittings in their plumbing department.
Fay Prozora
Member
Try the section in the HF store that has fitting for air compressors and or other pipe fittings. I did get some from HF but were not the right ones so went to Swains here in town and got one. I had to put a lot of thread tape on mine and screw it on good and tight. I still have a small leak some where but can't find it. Good luck.. Fay
NPT = National Pipe Tapered
NPS = National Pipe Straight
The threads are identical but there is a slight taper to NPT fittings. For best sealing, NPT-NPT and NPS-NPS is recommended. In general, NPS female on NPT male threads works fairly well but NPT female on NPS male threads is not as good.
However, if you use enough teflon tape, you can probably get by with an NPT female cap on an NPS male pipe. If you have leaks at that fitting though, you may need more tape or other sealant or look for an NPS cap.
FWIW, NPSM = National Pipe Straight Mechanical -- no difference from NPS, the M is simply used to avoid confusion with the abbreviation of NPS for "nominal pipe size"
NPS = National Pipe Straight
The threads are identical but there is a slight taper to NPT fittings. For best sealing, NPT-NPT and NPS-NPS is recommended. In general, NPS female on NPT male threads works fairly well but NPT female on NPS male threads is not as good.
However, if you use enough teflon tape, you can probably get by with an NPT female cap on an NPS male pipe. If you have leaks at that fitting though, you may need more tape or other sealant or look for an NPS cap.
FWIW, NPSM = National Pipe Straight Mechanical -- no difference from NPS, the M is simply used to avoid confusion with the abbreviation of NPS for "nominal pipe size"
lejones1445
Member
NPSM Cap
Thanks to everyone but I gave up and found another solution. Used a rubber stopper on the pipe inside the tank, first epoxy on the stopper, then covered the stopper and pipe end with more epoxy to seal. Finally filled the entire tube with more epoxy from the outside. After everything cured (gave it 24 hours) the seal worked perfectly! A lot easier than trying to track down that odd ball pipe thread fitting.
Thanks to everyone but I gave up and found another solution. Used a rubber stopper on the pipe inside the tank, first epoxy on the stopper, then covered the stopper and pipe end with more epoxy to seal. Finally filled the entire tube with more epoxy from the outside. After everything cured (gave it 24 hours) the seal worked perfectly! A lot easier than trying to track down that odd ball pipe thread fitting.
Dr Robert
Member
I have experienced the same problem with air leakage. I recently purchased a pressure pot from CA Technologies....Seemed superior to the HF brand. I cannot for the life of get a seal with the female cap off the male fitting. Anybody know what kind of thread is on the male... NPS or NPT... And what is the exact size of the fitting???