It's a simple question, but my search came up with no answers. Is there a DOT industry standard pipe joint compound used on the pipe thread part of air line fitings? Is just any old plumbing pipe thread compound acceptable? Teflon tape? I don't want to introduce more leaks by using the wrong brand. Thanks.
Well, this should bring many opinions from those that do their own work. I use Teflon tape. I have successfully used it for many years while I worked in the petroleum industry. The material is approved by numerous fitting vendors as compatible with their products used in gaseous service. For example, the molecules of air are much larger than molecules of hydrogen. The key is to get a correct application of the tape on the threads. Also, Teflon tape will not harden or crack, causing leaks.
Their is a right way and a wrong way of applying Teflon tape to a threaded fitting. First, always start the Teflon tape two threads back from the end of the fittings thread (the part of the fitting that is inserted into the threads). This will prevent tiny strings of the Teflon tape from being extruded in the air/process line (causing havoc plugging small orifices). Second, wrap the tape on the threads such that when the fitting is screwed in, the tape will will "tighten" and not become lose when threaded in. Simply put, grab the fitting in your left hand/fingers, with the threads pointing outward. Wrap the tape, starting from the top of the fitting, wrap away from you and pull under, then wrap min of 4 wraps and 6 in better.
I know this sounds technical in describing what many of us have done hundreds of times. This is the approved process demonstrated by representatives of this product.
Anybody use the Teflon in a can? It has an applicator and is sort of messy, but I have been using it, and of course no worry about direction of the wrap, just apply small amount (I basically fill the void between threads) and it is done. The mess is when I use my finger to smooth the coating out. If you were to use a small acid type brush, it can be a very nice/easy job. Just my $.03 cents worth (inflation!)
And then there are those who swear you need two wraps of teflon under your thread sealant. The answer appears to be whatever you're comfortable with. I've been using Hector's method, but wasn't sure I was doing enough. The Loctite thread sealant is priced about the same per ounce as your wife's best perfume. Jim, where do you buy the CNH stuff?
Your better auto parts stores might have it. I buy at a "farm/construction implement store", such as John Deere, New Holland, Caterpillar, Case. (they use this in house)
The product is good for hydraulic and can be found in such related places.
This product is from my bank of wisdom. Wisdom comes from experience and experience comes from mistakes and failure.
I have tried all the methods expressed and settled on my recommendation.
JIM
Senior Member
Air line joint compound?
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