We use teflon tape on high pressure oxygen (up to 10,000) and nitrogen (14,000)systems at work. The trick is to stay a couple of threads up from the bottom to keep from getting it in the system. Contamination in oxygen systems can be disasterous/fatal.
Teflon or thread seal on hydraulic hoses?
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Dead Horse
Platinum Member
Qua, thats is an interesting story.
I did a fair amount of boiler pipe fitting this past fall. A pipefitter friend of mine gave me some tips, one of which was he uses the tape AND pipe dope. A wrap and a half of tape and then the dope, making sure to not cover the first two threads.
Then he reefs down on the fitting to get it to the point of "tight" and THEN continues to turn it if necessary to fit the configuration required.
This is for pressurized domestic boiler systems, so I am sure there are differences in technique for hyd systems. I followed his counsel for all the fittings and have not had a single leak.
On the other hand, in working on my tractors, I have never seen any tape or pipe dope on the hyd fittings. The only time I have seen them leak is at the QD couplings and inevitibly an o ring is toast.........
I did a fair amount of boiler pipe fitting this past fall. A pipefitter friend of mine gave me some tips, one of which was he uses the tape AND pipe dope. A wrap and a half of tape and then the dope, making sure to not cover the first two threads.
Then he reefs down on the fitting to get it to the point of "tight" and THEN continues to turn it if necessary to fit the configuration required.
This is for pressurized domestic boiler systems, so I am sure there are differences in technique for hyd systems. I followed his counsel for all the fittings and have not had a single leak.
On the other hand, in working on my tractors, I have never seen any tape or pipe dope on the hyd fittings. The only time I have seen them leak is at the QD couplings and inevitibly an o ring is toast.........
Soundguy
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So...Just bought a 1/4" QD for gauge to test hyd pressure. I've always used tape, but I read this thread and took your advice. Made the joint with PTFE paste, connected it and...IT LEAKED!
Not a little either, it leaked a lot. Tightened it some more, then tightened it a lot. Still leaked. I didn't over do the sealer, but there was enough that a bead had to be wiped off when tightened.
Took it apart, cleaned, and remade with 2 wraps of teflon tape. Not nearly as tight as with paste. No leak.
Anybody need a slightly used can of paste?
Since pipe threads seal by thread deformation.. I'd say one or both of your taper threads were not correct if the paste didn't seal but the tape did.
IE.. cheap connectors probably made in 'riceland'
soundguy
