Pipe thread tape: Use the right color, the right way

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By Russ and Tiña De Maris

When plumbing water or gas lines, many RVers use thread seal tape, or “Teflon tape” as it’s commonly called. If you want to be technical, it’s actually PTFE tape (for polytetrafluoroethylene). But whatever you call the stuff, when doing these kinds of jobs it’s a pretty handy invention.

Since it comes on a spool, it’s easy to wind around pipe threads, not only to seal them against leakage but also, since the stuff acts like a lubricant, it makes it easier to tighten up the connection. We won’t get into the “Chevy vs. Ford” kind of arguments about pipe dope versus thread tape – that’s a subject for another day.

We would like to talk about the different kinds of thread tape and when to use them, and for some of us who tend to be a bit forgetful or clumsy (heaven forbid, some of us are both), how to properly use the stuff.

Colorful tape

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Yep, down at the hardware store you’ll find different colors of thread tape, and probably different widths. The colors exist for a reason to help both the installer, and in professional applications, to help the building inspector know what the installer used.

White is probably the most common for do-it-yourselfers. It’s a single density product, thin by nature. Use it for putting together water pipe threads, up to 3/8″. Yes, we probably hear a chorus of “Huh?” right about now. When you’re plumbing fittings are bigger than 3/8″ you need to take your product up a step to the pink stuff.

Pink is a triple density product, designed for those bigger-around water pipes. Use pink stuff when your fittings are 1/2″ up to 2″ in diameter.

Yellow tape is specifically designed for LP and other gas applications. Don’t use white tape for any gas line plumbing.

And just for reference, there’s also green thread tape. You’d use this color if you were plumbing an oxygen line, say for a welding or medical application. It’s an oil-free tape, which is critical for these applications. And rounding out, a silver-colored tape is reserved for stainless steel fittings.

Putting it together
First, thread seal tape is designed only for pipes with tapered threads. If you’re using a flare or compression fitting, let the fittings do their job on their own, don’t try to add thread tape or pipe dope. If (in those rare instances) where you have a straight, non-threaded pipe connection, a gasket is the only appropriate seal mechanism.

Using pipe thread tape is a fairly easily developed skill. Of course, one only applies thread tape to the male fitting. The secret is to apply the tape in the direction running the way the pipe turns to tighten. For most work, as we look into the receiving (female) fitting, the pipe will turn clockwise. That being the case, then:

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Hold the pipe in your left hand, with the threads at your right. Pull a length of tape free from the spool (but leave it attached). For a 1/2″ pipe, 3″ of tape is about what you’ll need. Press the free end of the tape onto the threads at the left side, and hold it there with your thumb. Now pull the tape and wrap it so that the tape goes away from you at the start. You should pull the tape hard enough that you can see the shape of the threads through the tape. Overlap the previous turn by a one-half or two-thirds and continue on down to the end of the threads. From here, continue to wrap the pipe, making a return route to the left end of the threads. You should do two to three complete wraps, but no more than that.

Be sure that as you wrap the thread tape you don’t encroach on the “opening” of the pipe. If the tape were to get in the water or gas stream, it’s possible it could break loose and move downstream – creating real clog problems.

Happy plumbing!

##RVT934

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Jesse Crouse
6 months ago

Gas valve manufacturers used to deny warranty claims if
teflon tape was used. They said it shredded and fouled the inside of the valve causing the failure.The yellow color denoted tape made for gas applications and was mandated by inspectors. Take your pick of these for why yellow tape is now allowed in some jurisdictions.

Sally
7 months ago

Rector Seal No 5. does it all . Nuff Said.

The bear 57
7 months ago

I worked as a pipe fitter for years .We used lot of Stainless fittings, which gulls very easily if over tighened. So we would use Teflon tape and then coat with liquid Teflon paste, it sealed great and acted as a lubricant too. Plus it was easy to undo if needed.

Cactus John
7 months ago

Yikes! The diagram shows the tape being applied counterclockwise, which is incorrect and will cause the tape to bunch up when the fittings are screwed together. The tape should be applied clockwise (as you look at the end of the pipe requiring tape). There are several YouTube videos that will show the proper way to apply pipe thread.

denver druesedow
7 months ago

when you purchase a new RV check to make sure yellow tape was used on the gas piping. I know this for a fact that some rv companies don’t know what is the difference

Tom
7 months ago

I was always taught to wrap the tape the same way the threads go. Start at the open end and overlay so as not to have tape unravel as to screw pipes together. Guess I better go fix all those jobs.

John Hartmangruber
7 months ago

Please explain why white tape should never be used on gas lines. I’ve used it for many years and have yet to blow myself up.

Vern
7 months ago

There is also another one that is blue, called Blue Monster. It is a good general purpose tape. https://cleanfit.com/blue_monster_ptfe_thread_seal_tape_70885.shtml

Tom
6 months ago
Reply to  Vern

I agree. Blue monster (available from Amazon) is much easier to work with.

Bob Harnish
7 months ago

How about the Mega Gray Tape?

Eddie
7 months ago

One of the propane connections went bad on my rv and started to leak. I wanted the part now so I went to camping world and bought the part and asked them to put the yellow tape on it for me as I was out of it. They came back with white on it and I said no it had to be yellow. They assured me that white was all they used so I tried it. Within a few weeks I smelled a leak again and I noticed the white tape was melting out of the connection and leaking. I took it off and cleaned it good and put the yellow tape on and no problem since. Oh, by the way, that camping world store has now gone out of business and completely closed down.

Billy Bob Thorton
7 months ago
Reply to  Eddie

Just a heads up, if your Teflon tape is melting, and your pipe is carrying propane, you have a whole lot more going on than just the color tape to be using!

Billy Bob Thorton
7 months ago

Marketing ploy. Teflon tape allows the threads to slide on themselves, allowing the connection to thread tighter, than had you used none. It also fills the micro spaces, which in turn, does not allow the escape of the medium the pipe is transporting. Nothing more, nothing less.

Wayne Caldwell
7 months ago

I know white is for water and yellow is for gas, but I didn’t know about pink. Thanks for the info.

Primo Rudy's Roadhouse
7 months ago

different colors? didn’t know that, now I do!

Bob Fuller
7 months ago

Good article, didn’t know about different colors for different jobs Bob

Robert
7 months ago

If white is thinner, can you just put more of it on instead of using Pink. Often all that’s available is white.

Wolfe
7 months ago
Reply to  Robert

A) Yes, you can — but remember the “2-3 wraps” directive. With larger pipes, it becomes harder to get a good seal.
B) Yes, you still can — you can use more than 3 wraps, but with too many wraps the tape starts bunching up and again sealing worse.
C) If you know you need pink, try to use that. If you don’t have it in an emergency, use white carefully. Generally, once I get out of “white tape range” I’m using dope on larger/sloppier fit pipes.

D) The dope debate: I really only use tape on stationary fittings because vibration can cause the threads to chew the tape over time. This being an RV maillist, I have a rubbery dope that never fully sets, which works well for the RV LP gas line. “Real” experts probably have an even better product/method, but I’ve had tapes fail where dope always works.

E) “tape goes away from you at the start” is the point of the whole article, but lacks the important words “upward in front and over-away.” I could go away and under, backwards from the intent. As diagrammed, the “loose end” of the tape needs to drag behind the rotation (stretching and tightening) rather than crumpling up.

Billy Bob Thorton
7 months ago
Reply to  Robert

In addition, slather it with pipe dope, you will never have a leak then.

Frank Billington
7 months ago

Thanks! I learned a few things there!

Bill Haas
7 months ago

I bought a gauge for my grill the other day and when I went to put it on it had yellow tape on the fitting. I have never seen colored tape on fittings. This article not only tells me about yellow but a few more also. Thank you!