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.
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:
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.