pipe thread?

[moored4]

If you use too much tape you can break/crack the fitting.

Always err on the side of liquid pipe dope as long as the fitting is a low pressure fitting only.

If your breaking fittings cause of 'too much tape' then I would suspect the fitting is not a Hydraulic fitting but just regular pipe! Make sure the system is all rated for the pressure it will see under load! :thumbsup:

 

[troutsqueezer]

I don't use anything, works for me. I just clean the threads. There is usually some hydraulic fluid you can dip your finger into and wipe it on the threads which helps lubricate the fitting.

 

[Deere Dude]

Loctite makes a sealant for use with NPT threads in hydraulic systems. We use it in plant maintenane w/o leaks.

X2
If I put a pipe fitting fitting together and I want it to leak, I'll use tape.
If I want to be able to take it apart again to fix a slow leak, I'll use paste.
If I don't want it to leak, I'll use Locktite.
But, anything is better than nothing.

 

[5030]

I would recommend using a sealant/lubricant on all NPT pipe fittings.

Not me.

A person needs to ascertain what type of thread it is prior to assembly.

If it's NPT dryseal, no additional sealant is needed or warranted.

Never use teflon tape on HP hydraulic fittings where there is a chance the tape could get in the flow to the pump prior to the filter. Teflon tape and HP pumps don't mix well.

Ues a proprietary sealant like Permatex or a made for hydraulic fitting sealant. Many are available at the hardware store.

NPT threads are designed to lock together to form not only a mechanically superior joint, but for the most part a fluid tight one as well. That's why they are tapered.

 

[J_J]

I am amazed at some of the post about sealing NPT threads.

No sealant at all, not good, you need more than metal to metal contact.

There have been standards for a good many years for sealing pipe threads, and some of those have been mentioned above.

 

[5030]

No sealant at all, not good, you need more than metal to metal contact
Absolutely false, depending on the type of thread (as I stated above) and the location of the fitting as it pertains the not only the fluid type but post-pre- filtering capabilities.

By the way, I have a high pressure operators license, do you? Go look up the ASTM specifications as they pertain to pipe joints when physically joined by corresponding threaded components, compatible sealants (if necessary) and their impact on various fluids.

I will say the most over the counter fittings are not dryseal but to make a blanket statement that sealant is required is false.

 

[High Compression]

When installing hydraulic fittings with one end pipe thread should i use tee tape there or just use the fitting bare?

I depends on the fitting. If it is a flare fitting, then you should leave it bare. Tighten to snug, then turn one flat spot more. (1/6 of a turn) If you over tighten flare fittings they will crack.

If it is a pipe thread fitting, no flare, npt, metric, British, or imperial, then I recommend pipe dope rated for petroleum. I have used tape, and it tends to start leaking after a while.

 

[955Lincoln]

Not me.

A person needs to ascertain what type of thread it is prior to assembly.

If it's NPT dryseal, no additional sealant is needed or warranted.

Never use teflon tape on HP hydraulic fittings where there is a chance the tape could get in the flow to the pump prior to the filter. Teflon tape and HP pumps don't mix well.

Ues a proprietary sealant like Permatex or a made for hydraulic fitting sealant. Many are available at the hardware store.

NPT threads are designed to lock together to form not only a mechanically superior joint, but for the most part a fluid tight one as well. That's why they are tapered.

Some of your information is good and some not so good. The OP asked a simple question about sealing so why mention a fitting (NPTF Dryseal) that there is a 99.99% chance he doesn't have? Or mention it for his knowledge and move on to what he probably has and include your thoughts on sealing.

NPT threads are not expected to seal dry and need a sealant.

 

[Mace Canute]

NPT threads are not expected to seal dry and need a sealant.

X 2! I don't know how many times the distinction between NPT and NPTF has been made in previous threads but apparently it hasn't been enough!

 

[LD1]

Another vote for the PTFE paste. (the white thick stuff).

EVEN on the NPTF I use it. IT doesnt hurt anything. And those seal by thread deformation. So If you have to remove and reassemble, sealant will probabally be the only thing that will keep it from leaking.

The only pipe thread that doesnt get sealant on what I work on, is NPSM fittings. These are where there is a cone (kinda reversed of a JIC flare) inside the swivel and it seals against the inside of the pipe, NOT the threads. Very similar to how a flare seals.