can I use pipe tape and thread sealant on hydraulic fittings?

[topofthehil]

I am installing fittings on my splitter build.
the manual for the hyd valve does not recommend using pipe tape on the hydraulic fittings. I'm looking at pics of log splitters on this web site and I clearly see pipe tape. what's up with that?
would it be ok to use tape on the final few threads?
also, they recommend not using thread sealant with Teflon.
why is that?
thanks for your help,
topo

 

[timberwolf]

High pressure seals need good metal metal or metal high pressure gasket fits, any soft fillers or tapes will just get pushed out by the high pressure. Adding goop or tape to what should be a metal metal fit will make getting that good tight seal difficult and promote leaks rather than prevent them. Simply they are not designed to work that way.

 

[leon]

hydraulic fittings

Timberwolf is absolutely correct in what he is telling you; I will add

several more reasons why this is not done.



You NEVER use pipe dope or teflon tape on the J.I.C. fittings which are the 37

degree bevel fittings; The J.I.C. fittings are a very close tolerance fit STEEL

machined fittings.



You must NEVER use more than a drop or 2 of the liquid pipe dope

MENT ONLY FOR HIGH PRESSURE SYSTEMS or when

installing fittings into valve bodies as the valve bodies are castings and MUST

only be used in the inlet port of the valve body or the fitting on suction side

of the pump as it is the low pressure side of the system.



Sealing threads of hydraulic systems with the teflon pipe tape is not done

because IT WILL CRACK FITTINGS AND CASTINGS.



When ever the Teflon Tape or TEFON BASED pipe dope is used it is being

used improperly, as it will promote leaks.


Leon

 

[sawkiller]

If you are talking a standard national pipe thread joint then yes a good qaulity teflon tape and a good qaulity thread compound is in order. The reason the manufacturer says not to use it is they do not want it in their pump or valves causing damage. My sugestion is do not tape the first thread and this will eliminate the above problem. Also read the directions on the thread compound that you get and it will tell you what it is good for and how much pressure. Gasoila compound comes to mind and with it no tape required but still keep the first thread clean.

 

[motoman3b]

From experince dont pipe dope wont hold up to high pressure lines, but for feed and returns it seals up good. The only thing I could get to seal mine is the permatex thread sealant they sell it napa.

 

[TreePointer]

Some of what you see may not be teflon tape. Hydraulic thread sealant can dry to look like white tape.

I've been using this from TSC: Permatex® High Temperature Thread Sealant

 

[PLAYINWOOD]

High pressure seals need good metal metal or metal high pressure gasket fits, any soft fillers or tapes will just get pushed out by the high pressure. Adding goop or tape to what should be a metal metal fit will make getting that good tight seal difficult and promote leaks rather than prevent them. Simply they are not designed to work that way.

Good answer Brian, may I add, goop and teflon tapes tend to gather in the vulnerable area called the pump.Not to mention gumming up filters.

Industry standards are NO sealants for hydraulic systems.Metal on metal thread,welded or compression fittings.Parker or swage-lok are the most popular compression fittings

What I have seen are machine threads with rubber O-rings on the male fitting.

 

[sawkiller]

Once again if it is standard pipe thread you need some sort of sealant when assembling and do not do the first thread and this will eliminate your in the pump issue. Of course I only went to school for plumbing for 5 years and hold journeymans cards in three states so I probably wouldn't know.

Below is a direct cut from the gasoila website and notice the pressure ranges with liquids. 10,000 PSI
Soft-setting, non-toxic, PTFE paste.
Provides a positive seal on pipe threads, joints, fittings, hoses, nozzles, LPG cylinders, pump assemblies, oil burners, hydraulics, compressors, engines, motors, housings, plugs, fuel lines, couplings and more.
Use on brass, copper, stainless steel, aluminum, black pipe, tin, galvanized, ABS, CPVC, PVC plastics, nylon, polyethylene, polypropylene, polybutylene and more.
Excellent resistance to gasoline (up to 20% alcohol and petroleum blends), petroleum solvents, kerosene, diesel oil, propane, butane LPG, cutting oils, ammonia, aliphatic solvents, acids, steam, potable water, compressed air and more.
NOT for use on oxygen.
Remains pliable in cold temperatures.
Temperature Range: -100ºF to 600ºF (-74ºC to 318ºC).
Pressure Range: To 10,000 psi sealing liquids; to 3,000 psi sealing gases.
One year shelf life when stored at 40ºF to 80ºF (5ºC to 27ºC).
For alcohol blended gasoline (ethanol),
see E-Seal.
For use on NPT Threads.

 

[PLAYINWOOD]

Once again if it is standard pipe thread you need some sort of sealant when assembling and do not do the first thread and this will eliminate your in the pump issue. Of course I only went to school for plumbing for 5 years and hold journeymans cards in three states so I probably wouldn't know.

Below is a direct cut from the gasoila website and notice the pressure ranges with liquids. 10,000 PSI
Soft-setting, non-toxic, PTFE paste.
Provides a positive seal on pipe threads, joints, fittings, hoses, nozzles, LPG cylinders, pump assemblies, oil burners, hydraulics, compressors, engines, motors, housings, plugs, fuel lines, couplings and more.
Use on brass, copper, stainless steel, aluminum, black pipe, tin, galvanized, ABS, CPVC, PVC plastics, nylon, polyethylene, polypropylene, polybutylene and more.
Excellent resistance to gasoline (up to 20% alcohol and petroleum blends), petroleum solvents, kerosene, diesel oil, propane, butane LPG, cutting oils, ammonia, aliphatic solvents, acids, steam, potable water, compressed air and more.
NOT for use on oxygen.
Remains pliable in cold temperatures.
Temperature Range: -100ºF to 600ºF (-74ºC to 318ºC).
Pressure Range: To 10,000 psi sealing liquids; to 3,000 psi sealing gases.
One year shelf life when stored at 40ºF to 80ºF (5ºC to 27ºC).
For alcohol blended gasoline (ethanol),
see E-Seal.
For use on NPT Threads.

**** runs downhill and payday is on Friday...I'm a plumber..

I work with a few steamfitters and worked construction as a millwright for 15 years.
Do you have a brand name of this hydraulic goop. My planner could do some research for us.I knew the first thread tape trick we use that in potable water.Plumbers dope for most everything else.
We have tried something by Loc-tite but it wasn't well received.

Hydraulic systems have always been a no no for us.

 

[sawkiller]

**** runs downhill and payday is on Friday...I'm a plumber..

I work with a few steamfitters and worked construction as a millwright for 15 years.
Do you have a brand name of this hydraulic goop. My planner could do some research for us.I knew the first thread tape trick we use that in potable water.Plumbers dope for most everything else.
We have tried something by Loc-tite but it wasn't well received.

Hydraulic systems have always been a no no for us.

You forgot the whole jingle in the last part the boss and everybody else is a SOB! LOL

"Gasoila" it is great and works extremely well. I have used it for hydraulics, gasoline, high pressure grease, air, and last but not least I could not imagine putting natural gas together without it. It is funny I have put quite a bit of steel pipe in and I have found that thread qaulity and tight but not broken is usually the trick.

 

[grandpatractor]

Should only use dope on pipe thread. JIC or o-ring don't need it.

 

[olyman]

Once again if it is standard pipe thread you need some sort of sealant when assembling and do not do the first thread and this will eliminate your in the pump issue. Of course I only went to school for plumbing for 5 years and hold journeymans cards in three states so I probably wouldn't know.

Below is a direct cut from the gasoila website and notice the pressure ranges with liquids. 10,000 PSI
Soft-setting, non-toxic, PTFE paste.
Provides a positive seal on pipe threads, joints, fittings, hoses, nozzles, LPG cylinders, pump assemblies, oil burners, hydraulics, compressors, engines, motors, housings, plugs, fuel lines, couplings and more.
Use on brass, copper, stainless steel, aluminum, black pipe, tin, galvanized, ABS, CPVC, PVC plastics, nylon, polyethylene, polypropylene, polybutylene and more.
Excellent resistance to gasoline (up to 20% alcohol and petroleum blends), petroleum solvents, kerosene, diesel oil, propane, butane LPG, cutting oils, ammonia, aliphatic solvents, acids, steam, potable water, compressed air and more.
NOT for use on oxygen.
Remains pliable in cold temperatures.
Temperature Range: -100ºF to 600ºF (-74ºC to 318ºC).
Pressure Range: To 10,000 psi sealing liquids; to 3,000 psi sealing gases.
One year shelf life when stored at 40ºF to 80ºF (5ºC to 27ºC).
For alcohol blended gasoline (ethanol),
see E-Seal.
For use on NPT Threads.

agree. i dont have your--"papers" but used pipe thread sealant, the stick stuff,many years ago when i built my splitter, near 40 yrs. no leaks yet

 

[Buckethead]

+1 for the sealant on NPT.

The tapered threads of NPT is considered a "crude seal" and certainly benefit from some sort of sealant. I've personally had better success with the sealant in a tube (teflon, Permatex, etc.) than teflon tape.

 

[PLAYINWOOD]

You forgot the whole jingle in the last part the boss and everybody else is a SOB! LOL

"Gasoila" it is great and works extremely well. I have used it for hydraulics, gasoline, high pressure grease, air, and last but not least I could not imagine putting natural gas together without it. It is funny I have put quite a bit of steel pipe in and I have found that thread qaulity and tight but not broken is usually the trick.

I'll do some research on it thanks,

If the thread dies were perfect we wouldn't need a sealant. The tapers of NPT thread pitch were meant to form a natural seal.

 

[mtfallsmikey]

Glad to see more of us plumbers around here....most pipe dopes are trash now, sice lead was banned from them years ago...

I use Rectorseal #5 on most everything.

 

[sawkiller]

That rectorseal or rectumseal as it is nicknamed works well to but I am not sure what the manufacturer pressure rating is for it?

And yes if the threads were perfect maybe less sealant needed. But let us not forget that the sealant is also a high pressure lubricant that allows it to slide together farther without damage to the pipe or fitting.

 

[topofthehil]

Ok, thanks for all of your advice.
Looks like I need some more schooling.
This is what I did so far.
I did not put any thread sealant on any of the high pressure fittings going into or from the pump, cylinder or the valve.
I hope to get these fitting tested some time this weekend with a live run.
I did put pipe dope on all of the pipe fittings that are on the hydraulic tank… except the first couple of threads.
This would be the supply from the tank and the return from the valve.
I then pressurized the tank and put soap water on the connections.
The 2” suction filter had a pinhole leak where it threads into the tank coupler.
So I removed the suction filter and put some thread tape and pipe dope on it, then tightened it up again. I retested it and it still has a pinhole leak.
The filter is made of aluminum, so I don’t want to over tighten it.
What can I do to stop the leak…RTV over the pinhole?
I did not use any of the “special” tube past sealants, I.E. Permatex, Gasoila... etc., just the standard plumber “brush on” non Teflon type.
Doesn’t PTFE paste have Teflon in it?
What does PTEF stand for?
Thanks, topo

 

[mtfallsmikey]

Ok, thanks for all of your advice.
Looks like I need some more schooling.
This is what I did so far.
I did not put any thread sealant on any of the high pressure fittings going into or from the pump, cylinder or the valve.
I hope to get these fitting tested some time this weekend with a live run.
I did put pipe dope on all of the pipe fittings that are on the hydraulic tank… except the first couple of threads.
This would be the supply from the tank and the return from the valve.
I then pressurized the tank and put soap water on the connections.
The 2” suction filter had a pinhole leak where it threads into the tank coupler.
So I removed the suction filter and put some thread tape and pipe dope on it, then tightened it up again. I retested it and it still has a pinhole leak.
The filter is made of aluminum, so I don’t want to over tighten it.
What can I do to stop the leak…RTV over the pinhole?
I did not use any of the “special” tube past sealants, I.E. Permatex, Gasoila... etc., just the standard plumber “brush on” non Teflon type.
Doesn’t PTFE paste have Teflon in it?
What does PTEF stand for?
Thanks, topo

PTEF is pure Teflon.

 

[kevin j]

PTFE is poly tetra fluorethylene (or soemthing close) the chemical name for teflon.


NPT threads MUST have a sealant of some sort. Functions for two reasons:
1. The threads do mate metal to metal but even with NPTF threads there still a small spiral leakage path between the top of the male thread and the root of the female threads. A sealant fills that small gap.

2. Lubricates the threads, reducse friction, allows tighter assembly with the same torque. Down side: allows tighter assembly with the same torque and can very easily distort valve bodies or split out casting ports from the higher wedging forces.


I prefer teflon tape, one or two threads back, and wound clockwise. Porbelry applied it is good and easy to do. But it must be done properly or tiny shreds end up in the system. For the more ham fisted people, Loctite PST or other liquid anaerobic curing pastes work well and less problems in the system.


NPT is a general PITA for fluid power. Many years ago the 37 degree flare (JIC, now SAE) became the most commonly used tube and hose connection.

Now, almost everything I design I use flat face oring seal (ORFS) connections. Combine that with an SAE o-ring boss port on the component (almost ALL hydraulic components outside of the cheap consumer stuff are oring boss ports of SAE or metric) and you will be almost leak free.

The only advatnage of NPT is the availability at Northern or places like that. Otherwise, NPT threads have no place in medium or high pressure systems.

kcj

 

[Iska3]

Glad to see more of us plumbers around here....most pipe dopes are trash now, sice lead was banned from them years ago...

I use Rectorseal #5 on most everything.

:agree2: