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Teflon tape can take the place of a good thread sealant, but there are plenty of other alternatives. Occasionally you even hear stories about people confusing thread sealants with thread lubricants or, worse, thread lockers.

Worse still, you may someday be told not to use super glue on threads, and the admonishment could end with, “Ask me how I know.” Duct tape isn’t the only substance that holds the universe together.

I’ve always preferred Teflon tape, because that’s what my dad used. Do you choose Teflon tape over the alternatives? Why, or why not?

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31 Responses to Hot or Not? Teflon Tape

  1. Nordmann says:

    I don’t understand. What could you have against Teflon tape? If you don’t use it on brass or copper connection you’re going to have a leak.

    Thread lockers are made to keep the parts together, Teflon tape is made to keep the connection water / air tight.

    I think someone works on more small block Chevys than kitchen sinks.

  2. elmegil says:

    I don’t use it on gas lines, but anything with water in it, Teflon Tape is the thing. Much less messy than the alternatives, easier for most spaces too (ever try to fit a tiny little brush 360 degrees around some fitting, and be sure you got enough on the back side you can’t see?)

  3. Jim Nutt says:

    It works fine on gas lines as well. I used to work for a flow meter calibration service that calibrated using a wide variety of nasty liquids and gases. We basically taped every joint. I did learn the correct way of putting it on (wrap with the threads) and to make sure it didn’t get in the flow path (was a real pain to get out of a turbine flow meter).

  4. Ray says:

    I was always thought that Teflon tape *was* thread lube and not a sealant. Are you suggesting otherwise?

  5. Fong says:

    As I understand it, Teflon tape is designed to prevent gauling, which occurs when 2 tapered threads of the same material are screwed together…that’s why it’s made of Teflon, one of the highest lubricity polymers Dupont has to offer.

    Side Note: I have no idea how much “Teflon” tape is out there as opposed to the generic PolyTetraFluoroEthylene (PTFE). PTFE tape doesn’t quite roll off the tongue but I digress.

    The tapered pipe threads we all wrap them around are “supposed” to seal. That’s why they’re tapered.

    In practice, we all know this is crap. Pipe threads never seal and without wrapping 3-4 layers of teflon, it leaks. Whenever possible, I’ll swap out NPTs for compression fittings. They may cost more but if it’s something hard to get to, it’s totally worth it.

    I prefer tape over “pipe goop” for a couple reasons.
    1. It doesn’t need to dry.
    2. It’s easy to remove.
    3. Messy factor.

    I have found pipe goop does a better job of sealing so for those problem threads, I keep a tube around just in case.

    Remember to read the MSDS and safety precautions on all liquid sealants. Unlike the more universal tape, goop has more specific application requirements.

  6. tooldork says:

    Do not use white teflon tape on gas lines…..use only the yellow tape for gas.

  7. jack says:

    HOT!

    hot or not even seems like a silly question when it comes to this. whenever i’m in the plumbing aisle buying pretty well anything to do with water and connections, i will pick up a roll.

    it costs $0.59 per roll, there’s no reason not to keep buying it just to make sure you have one handy. Advice for DIY newbie amateur plumbers: get in the habit of always always using it, never question if you should or shouldn’t use it, just do it.

  8. Teflon tape is such a trusty old friend I’d just as soon have a “Hot or Not? Hammers”

    Use it on everything threaded that you want to seal against fluids and might want to get off some day. EVERYTHING. You will regret it. When I was working with a lot of hot low viscosity waxes running through lines that had to come off about once a week, it was the only thing standing between third degree burns, insanity, and me.

  9. Brad says:

    “tooldork Says:
    May 7th, 2008 at 12:08 pm

    Do not use white teflon tape on gas lines…..use only the yellow tape for gas.”

    He beat me too it, so ditto. http://www.coasttape.com/html/yellow_gas_line_ptfe_thread_se.html

  10. fred says:

    I’ve been in the trade for over 40 years. Have seen sealants come in and out of favor. In my locality – threaded red-brass (copper – as opposed to yellow brass which was subject to de-zinc-ification) was once mandated. When I started there was still a lot of lead water services (street to house in use – with wiped joints) – and all waste and vent lines were caulked bell and spigot cast iron.
    NPT is a tapered thread form. If the threads are cut correctly (we still use our old Oster machines) and made up correctly – water lines will not leak. We always dope black iron gas lines and take pains never to back off on fittings once the threads are stretched. Understanding this bit of practical geometry helps prevent leaks.

  11. Terry says:

    I’ve used it for any plumbing or air compressor connections and think it works great. I’d say I love it, but I find it to be a ubiquitous tool. Would we say we love pencils?
    On the few occasions I’ve put on a new showerhead and not had tape around I’ve packed the threads with soap by rubbing a bar across the threads. This works well but I’ve suspected it may not be a great solution.

  12. BC says:

    The only time I use goop over tape is when driving a shallow well point. You run the risk of the tape losing its seal when you drive the point down into the ground. Otherwise, teflon tape works just fine – I’ve used it on piping for everything from solvents, to paint, to water. And since it’s dirt cheap, I have a roll everywhere – even on my desk right in front of me.

  13. SlowJoeCrow says:

    Personally I prefer Loctite PST anaerobic sealant to Teflon tape, especially cheap Teflon tape. The Loctite stuff is made for hydraulic lines and works on everything including gas grills.

  14. Bryan says:

    Can someone explain what happens when white tape is used on gas?

    I see that there is special tape for gas, but what is the difference?

  15. Old Donn says:

    Aside to Bryan

    Natural gas will break down regular white teflon tape. I’m sure someone else in this post who’s better versed on natural gases properties can tell you exactly why, all I know is it does break down.

  16. Brice says:

    Ok, they whole colored teflon tape thing is mostly a marketing gimmick to make you buy the more expensive stuff. You know that mil-spec number? (T-27730A). That’s the real thing. That number also OK’s you for use in oxygen service. Wanna have some fun? Smear a set of threads that will see oxygen service with oil. Then run. If you go to a pipe store (I’m a pipe fitter so I do it alot), and you ask for teflon tape, you usually get something white back, and it almost always has that number on it. I couldn’t care less what color it is, as long as it’s good tape, it’s going to get that number and you’re golden. I’ve never seen that number on the tape at Harbor Freight.

    That said, for air compressor fittings, teflon tape is all I use. It lubes the thread, keeps my pipes from being fouled with liquid dope, and does a great job of sealing the joint if applied properly and the joint is properly torqued.

    For low pressure gas service (15 in wc or less) under one inch, I use straight tape. For larger pipe, I add megaloc. It’s great stuff, that cleans up with just a rag. Very nice.

    For steam service I use teflon tape with some dark gray stuff, I can’t remember the name, but it’s a real pain to clean up. Most white pipe dope just boils out of the joint when you exceed 90lb so it doesn’t work very well. If you’ve got the big wrenches out, you’re almost always better off with just teflon tape for steam, it keeps the threads lubed enough so you can get the joint tight enough and it doesn’t boil when heated.

    For the record, compression fittings won’t hold 90lb steam (at least not the brass ones). A brass NPT joint will. Compression fittings are significantly weaker, flare fittings are much harder to make, but much more durable. Hardly anybody uses it anymore.

  17. fred says:

    Re Brice Says:

    In my area (union shops) steamfitters do most of the commercial steam work. For the really HP work it all welded construction – with some flanged work on old construction. Out in the burbs – where we do remodel work – we deal with some old steam heat systems – with threaded pipe. Breaking free old work is always a challenge – but our old Ridgid Compound Leverage wrenches help. Nothing like that chain to help hold the pipe in the offset jaws.

    For compressed air work – I need to let the steam fitters and the operating engineers sort out who does what.

    I second the use of Hercules megaloc – and in general we seem to use more Hercules compounds (including their teflon tape) than other brands (e.g. Rectorseal). We generally take what our supplier hands us across the counter – unless we have had some experience to say no.

  18. Michael says:

    I go through miles of this stuff at work (pool business). Every drain plug gets some, and would leak without it. And since they all need to be taken out at the end of the year, it’s nice to have something that’s easily removed, and not messy. The same goes with the plugs that go in the pool over the winter. Teflon tape and jack’s lube are a must.

  19. Frank Townend says:

    It makes great dental floss too.

  20. Dave says:

    I can honestly say I’ve bought dozens of rolls of Teflon Tape. I’ve never finished any of them, because as soon as I use it, I lose it and have to go buy more. I probably have a few miles of the stuff somewhere in my house. I think the problem is that the white tape exactly matches the white container, so my wife picks it up, sees nothing and throws the seemingly empty roll away. Since the tape weighs almost nothing it even feels like an empty roll. Maybe I should get the yellow stuff and use it for everything…

  21. monkeyboy says:

    Brice, I seem to remember there being a MIL-T-27730A & a MIL-T-277301 standard. One for Gas & one for everything else. I’m pretty sure regular tape is around 3 mils, while gas tape is +5 mils. Keeps little bits from tearing off & gumming up the gas valve. Otherwise, I think they’re the same. The gas tape might have originally been more resistant to petro-chem, but I think they’re both the same these days.

    Yep, I use teflon tape for just about everything. For galvanized water pipe though I like “real-tuff” teflon impregnated pipe dope from the same company that makes Megaloc. Great stuff!

    Raised by plumbers. It’s kinda like being raised by wolves, ‘cept I’m handy around the house…

  22. ToolFreak says:

    This stuff is a lifesaver, plus it always impresses everyone when they have a leak, you throw some on the threads, and it doesn’t leak anymore. I still usually put it on backwards the first time and have to redo it, though.

  23. J.R. Bluett says:

    Anybody have any stories about poor confused souls who used the wrong stuff? I’ve only got the one horror story about someone using super glue. I was guessing there might be some fun stories out there.

  24. Manny says:

    Anytime you mate mpt to fpt for the purpose of water, gas, glycol etc…, “teffy” is your answer. its the stuff to use. There should not be a “hot or not” discussion about it. If you have time and patience, applying a little pipe dope on top of your tef tape application wouldn’t hurt either. Maybe a little redundant to some, but sometimes it could just be that little extra touch that stops the leak that teflon tape couldn’t do alone.

  25. ambush27 says:

    Teflon tape is great, especially when it comes to air fittings.

  26. J.R. Bluett says:

    Sorry to post an obviously hot item under “Hot or Not” but I don’t have a category for “Which one is Better?” Thanks to all, by the way, for the “yellow tape” comments. I’ve never done any gas fittings or used the yellow tape.

  27. Alex says:

    I have had problems with Teflon tape ‘slivers’ getting into hydraulic directional valves and keeping them from sealing. For any installation that involves small air or fluid passages that could get plugged up, I recommend paste instead of tape. In any case, when tape is used it is important that it be started away from the very end of the pipe so it will not be cut off, which could create stringy, almost unbreakable debris.

  28. someonesdad says:

    Some comments:

    1. Teflon and PTFE are the same thing. The only difference between yellow and white Teflon tape is the thickness and color.

    2. Natural gas is mostly methane. It is not reactive with Teflon at all.

    3. Tapered pipe threads need to be sealed with Teflon tape or a pipe dope because there will always be a leak path — the threads can’t be machined perfectly so that they’ll interfere perfectly.

    4. Theoretically, the Teflon tape would also help avoid galling, but since pipe threads are cut with lubricants, this is almost never a problem. (But watch out if you’re using degreased stainless steel! :^)

    5. I use Teflon tape for the majority of pipe threads I connect, both on PVC and galvanized pipe. But when I really want a good seal that can’t leak, I use Titeseal #3.

  29. chris says:

    ever since i was little if something broke and it had to go back together my dad needed 2 things duct tape and teflon tape
    ok so thats a lie but you wouldnt know that with how many little blue rolls my dad leaves around the house
    this stuff is amazing i use it for paintballing to ensure a tight fit, that doesnt lock up and protects the threads because when youre putting a 150 dollar tank filled with 4500 psi of compressed air on the back of a 500 dollar gun you want those threads to last as long as possible and having to lube it up every time is not fun

  30. Squidwelder says:

    I can attest that this stuff goes faster than air when plumbing leaks comes up onboard. Take the joint apart and discover that the guy who put it together didn’t use any? Wire brush the inevitable green corrosion off and apply liberally for a leak-free win.

  31. kalwale lakhan says:

    sir, I want to know about alternative for teflon tape in injection mould..If any suggest and which will benefecial, as per cost is concern.

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