To avoid these ads, REGISTER NOW!

Pipe Dope

whejdak

Well-known member
Joined
Jul 20, 2011
Messages
176
Here is a stupid question, but I don't know the answer to.

Can I use the pipe dope that I use for sealing water connections on npt air connections.

Is it the same or different . Not talking about plumber puddy.
 
To avoid these ads, REGISTER NOW!

dogdog

Well-known member
Joined
Nov 15, 2011
Messages
12,711
I used it white pipe dope, in conjunction with the blue or white or yellow teflon tapes... which ever one I get my hands on if the thread is questionable. Only place you shouldn't do it is Oxygen Lines....
 
OP
W

whejdak

Well-known member
Joined
Jul 20, 2011
Messages
176
Mine just says "Oatey" Great White Pipe Joint Compound.
I'm sure it is the right stuff after reading the label over a couple of time...s
 

Spareparts

Well-known member
Joined
Mar 12, 2010
Messages
2,042
Location
Lansing Ks.
I don't use tape of any kind on air or hydraulic lines, someone will over apply tape and small pieces
always get into valves, especially pilot controlled valves.
 

ycgoat

Well-known member
Joined
Mar 28, 2020
Messages
971
Location
S.E. Va
I use pipe dope air line fittings, depending on the thread type it may not even be needed. None of my stuff is rated over 300 psi
 

msharley

Well-known member
Joined
Sep 20, 2021
Messages
13,930
Location
Central Pennsylvania
Here is a stupid question, but I don't know the answer to.

Can I use the pipe dope that I use for sealing water connections on npt air connections.

Is it the same or different . Not talking about plumber puddy.
Yes.

For screw pipe connections it will be fine.

Pipe Dope is a lubricant...allowing the tapered threads to "mate".
 

T444e

Well-known member
Joined
Feb 25, 2016
Messages
448
The same dope can be used, but I prefer Loctite 545 as well.
 

dogdog

Well-known member
Joined
Nov 15, 2011
Messages
12,711
I don't use tape of any kind on air or hydraulic lines, someone will over apply tape and small pieces
always get into valves, especially pilot controlled valves.
The correct way for those tape is don’t wrap it on the first thread
 
To avoid these ads, REGISTER NOW!

Monza Harry

Well-known member
Joined
Dec 29, 2018
Messages
1,433
Location
Windsor ON
I do not like the tape and dope approach at all. The proper dope is the answer. The 545, 567, and 590 are all pretty good but for stubborn leaks I use Loctite 577. I took a quick look at the "Henkel" site and without opening the MSDS's I didn't see the upper temp rating for any of these, and with compressor discharge temperatures of 300°+ possible that should be checked before making your final choice.
At 1 shop I worked at we were to use "RTV silicone" on pipe fittings as re-tapping the hardened parts at that time was problematic at best [deformed slightly due to heat treat] now that is considered pretty hack for sure but it did work], however changing your mind about sealant was equally problematic! RTV is also pushing the temperature limits as well. Edit: 650° should be enough. Harry
 

ALinCarolina

Well-known member
Joined
Dec 29, 2014
Messages
757
Location
NC Piedmont
Few years ago I called Rectorseal and asked whether #5 or Teflon would be indicated for compressed air and the CSR said either would be fine.
 

Doozer75

Well-known member
Joined
Oct 24, 2009
Messages
260
Location
Buffalo NY
The only reliable method I have found for sealing
3/8" NPT 10,000 psi hydraulic fittings,
is to apply Loctite 567 or 577 to the male fitting
and wrap over the Loctite with thick teflon tape
at least 4 turns. Yes your fingers will get full of
the sealant, but prepared correctly, this will seal
10,000 psi oil, and will not extrude from the threads.
I believe Loctite PST is the same stuff.

-Doozer
 
OP
W

whejdak

Well-known member
Joined
Jul 20, 2011
Messages
176
It looks like Loctite is the winner. Tape the loser.
I hadn't thought about the fact that the area I'm using it for is going to get pretty hot.
I'll look closer at the white stuff i was going to use.
 

housewolf

Well-known member
Joined
Feb 3, 2021
Messages
1,144
Location
East Texas
Rectorseal #5 has been my go to for a lot of years. If you have a leaking threaded joint, it isn’t likely because you used the wrong pipe dope. If you have a problematic joint that will not hold, like annealed copper threads, Expando will do the trick.

There is dope available for O2 piping
 

metalmagpie

Well-known member
Joined
Nov 1, 2011
Messages
796
Location
Seattle
If you mix red lead powder (litharge) and glycerine in the correct ratio and apply it to threads, the compound will dry hard as stone. This is old school and cannot be unthreaded without heat, but it will never leak.
 
To avoid these ads, REGISTER NOW!
Top Bottom