Pipe Dope vs Teflon Tape

[littleponderosa]

Best luck one vs the other? I was putting together a filter/regulator prior to a motor guard filter canister on the plasma arc when I found a small air leak at the pipe inlet to the filter/regulator. After 3 attempts with teflon tape I gave it up and went to pipe dope. Let it sit overnight and success. I've been using tape nearly all the time and now am questioning whether this is wise.
Any thoughts? Answers most appreciated.
Bill

 

[joe_padavano]

Best luck one vs the other? I was putting together a filter/regulator prior to a motor guard filter canister on the plasma arc when I found a small air leak at the pipe inlet to the filter/regulator. After 3 attempts with teflon tape I gave it up and went to pipe dope. Let it sit overnight and success. I've been using tape nearly all the time and now am questioning whether this is wise.
Any thoughts? Answers most appreciated.
Bill

I just had the opposite experience with house plumbing. I always use tape but tried some good quality, thick dope on some 1/2 brass threaded parts. About 2/3 of the joints leaked, and in one case when I tried to tighten the parts, the brass fitting cracked. I took it all apart and reassembled with good, thick tape. No leaks at all. I might use the dope on iron pipes, but not brass.

 

[dowmace]

What tape are you using? I rarely have leaks with quality tape like blue monster

Sent from my SM-N910P using Tapatalk

 

[thegroundpounder99]

I use liquid teflon and haven't had any issues. I just prefer it over the tape cause during a job hands are so greasy just easier and cleaner to use.

 

[littleponderosa]

Something I bought off the shelf somewhere. No clue on brand. Thinking napa/carquest of another parts shop. I've used it before on air supply lines with absolutely no issue.
Bill

 

[bcradio]

I am in the opposite camp too. Only issues I've had were with dope

 

[2mJps]

I work with alot of air and gas fittings. On some jobs were they used cheap junk i have had to use teflon tape and pipedope together to stop leaks.

 

[bonneyman]

I've always leaned toward pipe dope. Mostly residential gas line and furnace work.

I use Rectorseal Plus 2 with teflon. Maybe the best of both worlds?

http://www.rectorseal.com/index.php/rectorseal-t-plus-2/

 

[Dagny]

Rectorseal rocks.

 

[MacMcMacmac]

I prefer Master's pipe dope for anything liquid, teflon tape just disappears in oil. I think the Permatex liquid teflon sealant is best overall for cleanliness and ease of use.

 

[kiatech]

Tape, it has never failed me yet. I tried dope 2 times and it failed both times.

 

[warweapon762]

I typically use tape on exhaust studs for Mopar engine blocks (since they drill the holes straight into the coolant jackets. It holds up much better than dope in my opinion.

I've had some studs on my AMC Hornet I did the same thing to so I could remove the studs later for a head rebuild and was very surprised that it prevented the studs from corroding to the threaded holes in the cylinder head. These were on the engine from 1993 till 2014.

The best tape I have EVER used is the yellow teflon tape that is used for Natural Gas lines/fittings. That stuff is literally out of this world and very resistant to oil. I use it mostly on my air tools and that stuff has never leaked. Pipe dope on the otherhand almost acted like an anti-seize and I was constantly chasing down leaks all over my shop's air lines.

 

[mires]

I'm a plumber. I use Dope only on gas. Tape and dope together on water. The key with tape is to wrap it just 3 times (for the good thick stuff) and 4-5 times for the cheapo thin stuff. After you wrap the threads use the leading edge of the round tape container thingy to push the tape down into the thread voids. Just roll it around and actually push it down into the threads. Hopefully you understand what I'm saying lol. Otherwise when you thread on the fitting, most of the tape just gets pushed back and clumps together doing 3 things. NOT filling the voids which it is designed to do, sometimes preventing the fitting from threading all the way on because it is all bunched up, and making an ugly joint. And nobody likes an ugly joint. If it's gas, I stop there. If it's for water, I then spread just a very thin layer of pipe dope on top of the tape. Don't get too crazy with the stuff. It doesn't take a bottle per joint. I typically use Megaloc tape and dope but rectorseal is great too. Truthfully if used correctly, I have never had any brand of tape or dope actually fail me.

 

[Robinson1]

Air fittings I use tape, plumbing and gas fittings I tape the male threads and dope the female threads. I always use yellow pipe dope, have had good luck with the house brand True-Value sells. I think it's Master Plumber # 53.

 

[xela456]

Both, in the construction world time is money, how long does it take to dope and tape? Now how long does it take to take all that apart and redo it?

 

[kunkernator]

What tape are you using? I rarely have leaks with quality tape like blue monster

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Blue monster is the best and only teflon tape I would use.

I mostly use liquid teflon on brass fittings, and pipe dope on steel.

 

[justtools]

I use alot more pipe dope than tape. Rarely have a problem.

 

[justtools]

Blue monster is the best and only teflon tape I would use.

I mostly use liquid teflon on brass fittings, and pipe dope on steel.

Looks like you are getting ready to sit down with some contractors. When they give you the estimate. Ask if thats the best they can do.

 

[ddawg16]

Boy....a lot of misconceptions about the two and when to use them.

The primary purpose of both is to reduce the friction of the threads so you can get more turns. It's the actual compression the threaded joint that creates a mechanical seal, not the tape or dope. The tape or dope just reduces the friction for more turns.

To a great extent, it depends on the type of threads. Tapered threads, tape is fine. Straight threads....dope.

Other times to use dope...steel pipes where your concerned about corrosion.

If you do a search on the internet, you will find the same discussions...along with good and bad info.

 

[larry_g]

It seems that we have tapers and dopers here. There is a place for each and neither will work in every situation. I've seen knotheads that use tape on flair fittings. There are different tapes and dopes for for different applications. Gas fittings require a different sealant than water fittings. There are a few dozen different dopes out there, and some for good reason. If you consider that Teflon is not a sealant but a lubricant for threads that are tapered then you answer may become apparent. Study tapered pipe threads, learn how they do not seal at the root/peak interface and the role that a sealant or lubricant plays.

There is also the issue of what you are fitting together. Some air system in the garage with home depot fittings or some hi-tech equipment with Swagelock fittings where no leakage is permitted, and assembled fittings are gauged to make sure they are assembled to specifications.

This is another one of those subjects where so many inputs from so many from different people of varied backgrounds and skills completely render the answers useless. OP if you get specific about what fittings you are using, what fluid are you sealing against, fitting materials, and any other variables that may apply then you can get an answer. This question is akin to asking whether air or water is more important? I would have to ask, are you drowning or stranded in the desert?

lg

no neat sig line

 

[Packard V8]

plumbing and gas fittings I tape the male threads and dope the female threads.

Both, in the construction world time is money, how long does it take to dope and tape? Now how long does it take to take all that apart and redo it?

Agree. Why not use both? Most good plumbers I know do.

jack vines

 

[Backpack Hunter]

I use dope, mostly work on LPG fittings, obviously never on flair fittings. Never have a problem.

 

[dogdog]

I hope ppl still do the basics which is wrap it clockwise with the threads facing you...... haven't have one failed yet with cheap or expensive tapes.... that is not due to my mistakes.

 

[garfunkle24]

Never had a failure with tape, had a few with dope.

 

[defektes]

Im a maint mechanic at a wastewater plant we do plenty of pipe work, some of us use tape, others use dope.

I prefer tape for smaller fittings up to 1'', anything over I use plenty of dope and just wipe the excess.

On the SCH80 PVC we use, I only use tape, as the dope can cause you to over torque the PVC.

I wrap the fitting 3-4 times and then use my hand to "tighten" the tape as if I were spinning a fitting on it. It will cause the tape to sink in and grab the threads.

I have only really had issues with cheap Chinese iron/brass fittings that are not of the same quality as good US fittings.

 

[Piper27]

I'm a plumber. I use Dope only on gas. Tape and dope together on water. The key with tape is to wrap it just 3 times (for the good thick stuff) and 4-5 times for the cheapo thin stuff. After you wrap the threads use the leading edge of the round tape container thingy to push the tape down into the thread voids. Just roll it around and actually push it down into the threads. Hopefully you understand what I'm saying lol. Otherwise when you thread on the fitting, most of the tape just gets pushed back and clumps together doing 3 things. NOT filling the voids which it is designed to do, sometimes preventing the fitting from threading all the way on because it is all bunched up, and making an ugly joint. And nobody likes an ugly joint. If it's gas, I stop there. If it's for water, I then spread just a very thin layer of pipe dope on top of the tape. Don't get too crazy with the stuff. It doesn't take a bottle per joint. I typically use Megaloc tape and dope but rectorseal is great too. Truthfully if used correctly, I have never had any brand of tape or dope actually fail me.

Exactly right on the money

 

[walrus]

Rectorseal #5 been using it for almost 40 years. Rarely use tape. Its easy, cheap and works great or I still wouldn't be using it. I see folks wrapping with Teflon and then using dope. Not sure what that does but it takes valuable time

 

[2mJps]

I see folks wrapping with Teflon and then using dope. Not sure what that does but it takes valuable time

I dont totaly under stand it but for me it has sealed a leak several times. Something else i do and it has worked is on the fuelline on my 67 GMC is use tape on the threads to stop it from seeping gas. This is a flared fitting.

 

[wkndwarrior29]

I've not had any air leaks since I started using both - 3 wraps of tape then a good coating of dope.

 

[Heavy Metal Doctor]

Funny...some are saying the material is put on only to lubricate the threads, but I don't recall seeing any MFR refer to this stuff as anything other than "sealant". But, I am in no way any expert, I just work with high pressure water and hydraulic systems. We try very hard to never use tape as there is a chance of a chunk tearing off and getting jammed in some critical tiny orifice within the system. I will opt for tape on low pressure / non-critical / poorly MFR'd fittings.

 

[engineer2]

Uncle Jim who spent many years at the NICOR gas company ("head ditch digger" he would say with a laugh) said to always put dope on the male AND the female threads. Been following his advice for years and no problems.

 

[MJD1]

The best stuff I have used is permatex hydraulic and pneumatic sealant. Kind of like loctite, except easier breakaway. Works really good for metal threads into plastic valves where getting the fitting turned correctly would lead to over tightening.

 

[plinker]

At work we had problems with NPT hydraulic fitting's leaking so they ditched teflon dope and got us Loctite 545 and the problems went away for the most part. Cheap fittings were likely the culprit more then anything.

 

[slip knot]

I had this same conversation with my plumbing contractor a couple of years ago. His response was tape and dope is cheaper than his hourly rate. He used both on just about everything. He said years ago they used grease as a lube and could make up joints tight enough to not leak with no sealant. Somewhere in the 70s foriegn components started arriving here and he started getting the leaks. Now, he said even the dope and tape dont garantee no leaks.

He did drop me a box of Blue monster tape and dope a while back and told me to use them and see what I thought. They seem to be pretty good.

 

[Ainsley]

I use orange Teflon tape (6 mil) and pipe dope on top. Would always use one or the other before but since I switched to using both I have had way less leaks.
Oh, and always use anti-seize on unions and valve stems.

 

[FullRaceMerc]

For water I have used dope alone for years. After one job with issues during testing which needed several locations pulled apart I use the dope tape dope routine.

For gas I use dope.

Inline to an ice maker I use only tape. Taste from dope is hard to clear from an ice maker.

 

[NorCalWrenchin]

Neither. RTV of any color for air line fittings in the shop...

 

[Jlarson]

For shop air stuff 3 wraps of blue monster (wrapped correctly) and don't get tape on the end of the fitting.

 

[southpier]

i've been cautioned to not use tape on PVC threads lest it crack a fitting

 

[McFarmer]

I am of the opinion to use both.