tomrscott
Gold Member
What do you recomend for hydraulic thread sealant when you have to use NPTx fittings?
I would rather use some fitting that seals better and more easily than NPTs, but the fact is that a lot of what I am going to run into is going to be NPT and not ORFS or something else more appropriate to HP. So what works the best for you?
The guy behind the counter at the local hydraulic service shop said he prefers Loctite Hydraulic Sealer, but he warned, "Just be sure you've got it put together the right way the first time! Gosh awful hard to get apart if you goof. But I've never seen it leak!"
My dad got me started using Permatex #2, the black pasty stuff, because it seals real well (for general plumbing and gas, but haven't used it for HP Hyd), and with some effort you can get it back apart. It never turns rock hard, but quickly reaches the consistency of cold tar. I believe the container says it is good for hydraulics. I think dad became sold on it back during WWII at Lockheed when they used it on aircraft hydraulics (could be wrong about that, I'll ask him). I have never had any trouble with Permatex #2, ever, even with really ratty threads cut in pipe made of cheap steel. Just don't wipe it on a pair of jeans you ever want your wife to let you wear out to dinner! /forums/images/graemlins/grin.gif
Seems like I've read somewhere here a recomendation against teflon plumbers tape which sounds like it is probably real good advice.
Anything else I should try?
Do you have to be careful not to put too much on so that you don't get any excess squeezing inside that could contaminate a cylinder or valve?
Also, I've noticed on the high pressure fittings I picked up at Columbia Hydraulic Service, that the threads start to get tight almost as soon as you get one or two threads engaged. How much torque is appropriate for 1/4", 3/8", and 1/2" NPT threads?
I am about to thread together a few fittings to hook up a pressure gauge, need one or two more things first, but thought I would see what experiences others here have had.
Thanks! I appreciate the collected wisdom here.
I would rather use some fitting that seals better and more easily than NPTs, but the fact is that a lot of what I am going to run into is going to be NPT and not ORFS or something else more appropriate to HP. So what works the best for you?
The guy behind the counter at the local hydraulic service shop said he prefers Loctite Hydraulic Sealer, but he warned, "Just be sure you've got it put together the right way the first time! Gosh awful hard to get apart if you goof. But I've never seen it leak!"
My dad got me started using Permatex #2, the black pasty stuff, because it seals real well (for general plumbing and gas, but haven't used it for HP Hyd), and with some effort you can get it back apart. It never turns rock hard, but quickly reaches the consistency of cold tar. I believe the container says it is good for hydraulics. I think dad became sold on it back during WWII at Lockheed when they used it on aircraft hydraulics (could be wrong about that, I'll ask him). I have never had any trouble with Permatex #2, ever, even with really ratty threads cut in pipe made of cheap steel. Just don't wipe it on a pair of jeans you ever want your wife to let you wear out to dinner! /forums/images/graemlins/grin.gif
Seems like I've read somewhere here a recomendation against teflon plumbers tape which sounds like it is probably real good advice.
Anything else I should try?
Do you have to be careful not to put too much on so that you don't get any excess squeezing inside that could contaminate a cylinder or valve?
Also, I've noticed on the high pressure fittings I picked up at Columbia Hydraulic Service, that the threads start to get tight almost as soon as you get one or two threads engaged. How much torque is appropriate for 1/4", 3/8", and 1/2" NPT threads?
I am about to thread together a few fittings to hook up a pressure gauge, need one or two more things first, but thought I would see what experiences others here have had.
Thanks! I appreciate the collected wisdom here.