NPT thread sealant ....
NPT thread sealant ....
Most of my connections are SAE (o-ring). From what I read this is a great seal and most of the items I ordered only gave this option as a connection.
However pump and cylinder (being 30 years old) have NPT connections (thinking about it, gauges still seem to all be NPT).
I did my usual web search and found everyone has an opinion.
I found people suggesting: nothing (since the threads are tapered and should lock in place), Teflon tape (just don't get any over the edge of the pipe, Loctite 545 (with or without primer), Permatex 54540, Rectorseal 5, .......
I even saw one person say that NPT threads are only to be used once.
There is only a few NPT connections but I want to make sure they are leak free.
What is the "best" sealant to use on them (cylinder is 3/8 ... pump 1/2 and 3/8 .... filter 3/4)?
Thanks again ..... Mike
PS ... I have a bit of a phobia when it comes to NPT thread. I have had NPT threads leak so I make sure they are "tight", like two 24" pipe wrenches tight. When building our house, the "certified and licensed" installer, finished the gas pipes, pressurized the pipes to 10 PSI, said they passed and then left for the night. He made the mistake of leaving his test gauge on the system. I noticed the next day the gauge had dropped to zero. I pumped the pipes up to 10 psi and started with the snoop .... one leak ... two leaks ... three leaks! I was getting tired of looking. I put 50 psi in the pipes to make it easier to find the leaks. WOW .... 14 leaks !!!!!!!!!!!!
I called the gas company, they said if it passed his test then there was nothing they could do. I called him. He said I should never have put 50 PSI into the pipes as it "blew out" the sealant. What a crock or s**t. He would not fix it.
So I took everything apart, cleaned the connections (many had very rough threads ... I could tell he needed new dies on his threader) and put it all back together. I bought a new gauge ( he had a 0-100 gauge ... could not even see if it lost 1 psi ... I bought a 0-25 gauge) put 20 PSI on the system ...... a week later still holding 20 PSI. I should have just bought a threader and done the job myself. He never did finish the job (and I made the mistake of paying him as he went along so he got the majority of the money). I still don't have return runs in the house. I will get to these one day.