Compressed Air Thread Sealant

MFan

Member
After a couple unsuccessful attempts to seal the air lines I'm installing in my workshop with Oatey and Harvey's thread sealant, I'm looking for advice on a better thread sealant to use. The main run that I'm working on is 1 in. black pipe.

With the research I've done, I'm leaning towards using Rectorseal #5 with a couple wrappings of teflon tape to help lube the joint. Can someone talk me out of that and convince me that Loctite 565 or 567 PST would be better? Or something similar from Permatex?

Bottom line is that I want this installation to be the last.
 
It shouldn't be real tough to get a black pipe compressed air system sealed up!

Are the threads "good" on the pipe?

Fittings from "The Land of Almost Right", perhaps?

A couple of those got mixed in on a propane piping project a while back. They leaked, even with thread paste "for gas", and I had to take part of the job apart and toss 'em. NOT swell!
 
I wouldn't have thought that it would be that difficult, either. The fittings are not from around here, but it's pretty hard to find otherwise. Most of the leaks were only noticeable with soapy water, but I hate to have a system like that from the start.
 
I have done air lines in four shops over the years the same way you are with one inch black pipe.
Hundreds of feet and countless fittings.
All I have ever used is the thick yellow teflon tape.
Years of use and never a leak in any of them.
The important thing is to tighten it up like you mean it.
Then give it another half turn.
 
i use teflon tape and harveys tfe paste. seems to work good. the new import pipe thread leaves a little to be desired.
 
You need longer pipe wrenches. I wouldn't use anything smaller than an 18 inch pipe wrench on 1 inch pipe. Probly one 18" and one 24" pipe wrench. I buy Teflon tape by the case and I wrap over lap at a third the width of the tape. I have to take pipes apart and put them back together every time I change mold inserts which can be several times a week. I use both 1/2" and 3/4" wide tape.
Black or galvanized pipe for air I tighten until it does not leak. The threads are tapered and the farther they screw in the better the seal. Pipe paste would work just as well for air lines as tape.
 
As a pipefitter, I was taught exactly 3 wraps of teflon tape starting 1 thread back from the end, and some Rectorseal or other good pipe dope. I've had very few leaks over the years using this method, and I've put together thousands and thousands of joints, all pressure tested after installation.
 
one thing NOT TO USE Anti Seize. gave my helper the can of pipe dope in his hand and said use this while I worked on another job in the shop he gets done tun on the air to that line all I hear is air leaks ask him if he used the pipe dope he hands me the can of anti seize! spent the second shift fixing it.
 
I was a fan of Rectorseal 5 until I accidentialy recieved Rectorseal T+2 in an order. Much better product. I can't recall the last time I had to redo a joint because of non seal.
 
Second Rectorseal - all I use for pressure and vacuum. I usually do a quick dry fit of a joint before I dope it. Given the loose tolerance of store bought fittings, it is a good idea. If something does not quite go together the way it should - try a different fitting, chase the existing one or add tape to make up for a loose fit. You can try tightening more but watch out for galling - you'll ruin the joint and it still may leak.
 
LA-CO Pipetite Stik, LA-CO Industries, p/n 11175

Grainger carries it. If its cool it works better if you heat it for a second in a propane torch flame. Rub it on the threads and assemble.

Charles
 
(quoted from post at 11:49:38 04/04/14) I have done air lines in four shops over the years the same way you are with one inch black pipe.
Hundreds of feet and countless fittings.
All I have ever used is the thick yellow teflon tape.
Years of use and never a leak in any of them.
The important thing is to tighten it up like you mean it.
Then give it another half turn.



ahhh, im not so sure about that advice. i was helping my neighbor replace a bad repair job on the gas line to his house and i told him to make sure he snugged it up real good. it was 3/4' blk pipe and he tightened it so much that he broke it, twice. the guy didn't know his own strength.
 
Nothing wrong with rector seal #5. It's just messy and hard to clean up. I prefer rector seal t2 or mega loc both these have Teflon. I use a couple wraps of heavy Teflon tape and mega loc. It's redundant but was the way I was taught 30 years ago. Only leaks I've ever had was due to bad fittings to threads.
 

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