Pipe Joint Sealants

Richard Rogers · Jun 1, 2007

I've, of course, used teflon tape for years on air or water fittings. I've used it on hydraulic stuff, and I understand that can be frowned upon, because it could end up clogging something, etc, in the hydraulic system, so I don't do it much. I've used the "pipe dope" stuff, and by using that term, I'm lotting many brands of "stuff from a tube or brush-on can" that you put onto pipe threads to seal them.

I was very pleased last year with a product from LocTite that I stopped a leaking fitting in an Allison forklift transmission by using. Only problem was it was not cheap, but still worth the expense for this hard-to-reach fitting.

What do you find works in what instances? What brands and products do well for you? What has let you down? What has pleasantly surprised you? What stuff has a good or poor shelf-life?

As a "by the way" thing--How many times can NPTF fittings be removed/retightened and retain their "better than just NPT" qualities?

I guess I'm just on the subject of leaks and preventing them because my Pop was fixing air leaks all over the shop today, and leaks are a problem I'm sure has nagged us all.

Richard

mark costello · Jun 1, 2007

Bought a new water heater, almost all installed, no amount of teflon tape or any other kind of pipe sealer would work to stop leaks on oversize threads in water tank. Last tank in store at that time. Finally tried good old Permatex #2, success

Richard Rogers · Jun 1, 2007

I've used Permatex no 2 as a gasket sealer for ages, but never used it on threads! Neat to know!

Richard

matt_isserstedt · Jun 1, 2007

I have had good luck with Loctite PST for air, water, and hydraulic fittings.

Best, though, was probably red loctite 272. I drilled and tapped my brother's aluminum oil filter adapter housing for a pressure transducer for a dash-gage. The aluminum casting was thin and the transducer pretty heavy. That was about 4 years and 80,000 miles ago, and left a very good impression on me

Davis In SC · Jun 1, 2007

All I will use anymore, is the Loctite sealant. I am not sure of the # , 562? It comes in the squeeze tube, a little goes a long way. In addition to working as a dope/lube, I think it uses some of the same anerobic properties of the other Loctite products, in that it sets up, in the absence of air. Just one leak saved, more than pays for a full tube..

Richard Rogers · Jun 1, 2007

Straying from the original thrust of the thread (no pun intended) here but this could also be a useful thing to mention. Story below.

I had a 200 gallon diesel tank. It seemed sound in all ways to me. I took it and put more than 150 gallons of off-road fuel in it. Before completely full, I noticed something.

Uh oh. It had a leak. A little crack that was dripping about like tears rolling down a face. NOTHING would stop it. The diesel would not let anything I tried stick to the crack. Then, I called a truckdriver friend of mine, who's a wizard at "getting the thing back on the road" if you know what I mean!

He told me to take a bar of soap, and scrape it along the crack like grating cheese or something. It would smear into the crack and hold it a while. Worked!

Not permanent, but it lasts a while, even weeks, between applications. I think he said it can work for gasoline too. I'll fix the tank after I've burned this fuel!

Richard

Mike Folks · Jun 1, 2007

The Loctite PST is good for metal pipe fittings but is not something to be used in a plastic/metal enviroment because the joint will fail/disolve due to the chemical in the joint compound(listed on the back of the tube).

Bill's Machine Shop · Jun 1, 2007

Locktite expands in the threads when it cures. Therefore do not use it on plastic threaded parts. If used on nylon, the outside part will shatter.
In joints using copper tube with the compression brass ring, clean the copper tube and the inside of the brass ring. Place a small amount of soldering paste on the clean tube and the inside of the ring. Install the joint and lightly compress the brass to keep it in place. Disassemble the joint and solder the brass ring to the tube. Then install the joint using a couple wraps of teflon tape. Never leak again. Always use flare nut wrenches. WWQ

Richard Rogers · Jun 1, 2007

What's good on metal-to-plastic connections or plastic connections in general? What sealant works best in fuel connections?

Richard

DobermanDave · Jun 1, 2007

old Permatex #2, works great on pipe fittings.

Jon Frary · Jun 2, 2007

Best stuff I have used was Leak Lock from High Side Chemicals, pricy but never a leak. Something similar is MegaLock from Hercules.

Richard Rogers · Jun 2, 2007

I found some Leak Lock on eBay. I ordered a couple tubes, and will see what it's all about! Thanks!

Richard

acme thread · Jun 2, 2007

My 86 yr.old rancher buddy in Wyo. was looking at his leaky radiator in his pickup;when I walked up.Tring to be helpful,I mentioned a friend told me if you break up a couple of cigarettes and put them in the radiator,it will temporaraly stop a pretty good leak. Old Earl says " YEA! But cigarettes cost money,A horse turd will work just as good" I had no answer.

Michael Moore · Jun 2, 2007

Loctite 567/PST works for me.

cheers,
Michael

jabezkin · Jun 2, 2007

loctite 545!!

R.P.C.MAN · Jun 2, 2007

I use teflon tape on air systems,and have used most of the high tech stuff,dont know if im just old,but i agree permatex #2,its got me out of leaking fitings,water,oil,and gas.I even use a small amount on gaskets

jabezkin · Jun 2, 2007

Loctite 545 for hyd & pneu, no time wait and 4500psi no problem
Loctite 290 for sealing weld cracks and all ready assembled fastening, clean a little and let it wick in.

jim rozen · Jun 2, 2007

SWAK. It's an anerobic teflon-based pipe joint
compound. Works great.

OTher than that, teflon tape. Don't tape over
the first thread on the male fitting. Then the
stuff can't get into the system to jam anything.

If you're doing a house job where it has to be
tight or else, tape, then the blue block pipe
dope on top of the tape.

Jim

2Slow · Jun 2, 2007

Loctite 567 is wonderful stuff. Once I switched to it, I have never had a fitting leak.

I use it for air lines and gas lines. I don't think it is rated by NSF so I do not use it on drinking water lines.

-Joe

Andreas · Jun 2, 2007

My God, for tight pipe joints there is nothing like linen or flax I think, that with linseed oil, whoow.
I had a fitting in my office that at plumber had mounted, hot water an all. I called him up said it was leaking. He answered is it much, Na few drops a minute, I told him. Then don't worry. After a few hours it was tight and stayed tight.
In my houses I have every joint with flax and oil, and there are many joints thanks to thermal pump heating and such. Nowhere one drop has ever elaked in ten years. In the summer house I tried with teflon tape, totally useless. It always creeps enough so you can see corrosion building up. Nowhere has that happened where I used flax.
All plumbers around here use flax, that nowadays comes in convenient packages just to put a few turns around the threads, a few drops of oil then it's tight for a hundred years. AND it's dirt cheap. One pal of mine tightened his steering knuckle on a terrano with flax, instead of buying spareparts for hundreds of $. Just one washer to keep the flax in place. Flax is great for compressed air as well as low pressure steam.

Flax is future.

Andreas Wahlberg

Andreas Wahlberg

Pipe Joint Sealants

Titanium

Stainless

Titanium

Diamond

Diamond

Titanium

Cast Iron

Hot Rolled

Titanium

Cast Iron

Cast Iron

Titanium

Stainless

Titanium

Stainless

Cast Iron

Stainless

Diamond

Hot Rolled

Aluminum

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