# Thread prep



## plumberdad70 (Sep 29, 2012)

Ok, I'm going to start some s**t here!! When turning screw pipe on a hot water boiler how do you prep your threads?? Dope, tape, dope then tape, or tape then dope, or what???


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## rocksteady (Oct 8, 2008)

Water pipe gets tape then dope, gas gets dope only.










Paul


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## Titan Plumbing (Oct 8, 2009)

Already been done...

But, for the heck of it...tape then teflon dope.

Half union on the gas regulator, tape only.


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## plumberdad70 (Sep 29, 2012)

I'm talking just the water!!


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## johnlewismcleod (Apr 6, 2012)

Tape, then dope or plumbers grease :yes:

True Blue dope makes tape nearly as slippery as grease so the tape always gets into the threads well and seals without exception, but it's nasty stuff.


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## rjbphd (Feb 5, 2010)

Any threads over 2 ".. or bad threads.. expANDO !!


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## johnlewismcleod (Apr 6, 2012)

rjbphd said:


> Any threads over 2 ".. or bad threads.. expANDO !!


What's expando, RJ ? (or did I just fall for a punchline? :whistling2


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## plbgbiz (Aug 27, 2010)

johnlewismcleod said:


> What's expando, RJ ? (or did I just fall for a punchline? :whistling2


http://www.xpando.com/pjccert.html


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## johnlewismcleod (Apr 6, 2012)

rjbphd said:


> Any threads over 2 ".. or bad threads.. expANDO !!





plbgbiz said:


> http://www.xpando.com/pjccert.html


Whoa! Now that looks like something I'd like to try out (it also looks like something the dummies that put dope on the female threads could really f-up some piping with :yes::laughing


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## user4 (Jun 12, 2008)

johnlewismcleod said:


> What's expando, RJ ? (or did I just fall for a punchline? :whistling2


20 years later the guy trying to take it apart needs a torch and a set of chain tongs to get the pipe apart.


All threads on IPS pipe over three inches get Expando on top of the strip of bed sheet we use for tape, because threaded cast iron pipe just plain sucks to put together.


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## rjbphd (Feb 5, 2010)

EXPANDO is damn good stuff.. to take it apart 20 years later, a couple of whack with both hammer will loosen it up.
You MUST follow the instructions when using it. Its comes in powder form and mixed with water only enough to do the job within time frame. I used it all the times for large bushings into boiler and with bad pipe/fittings threads.. newer can doesn't say so ( due to masa data) its recommanded for putting together on ship boilers and fittings/piping.
By the way.. aren't we all over 50 years old and worry about someone else taking it apart 20 years later????


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## Widdershins (Feb 5, 2011)

Blue Monster PTFE on potable and hydronic systems or Laco SlicTite. Generic yellow PTFE or Laco SlicTite on gas piping.

You folks who feel the need to double up with PTFE and Dope lack confidence in your abilities.


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## Titan Plumbing (Oct 8, 2009)

Widdershins said:


> Blue Monster PTFE on potable and hydronic systems or Laco SlicTite. Generic yellow PTFE or Laco SlicTite on gas piping.
> 
> You folks who feel the need to double up with PTFE and Dope lack confidence in your abilities.


You know Widder, I'm not sure where all this started with us "doubling up". For years RectumSeal was good enough by itself, then came some of the new super dopes and then all of the sudden we found the need to "double up".


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## Widdershins (Feb 5, 2011)

Titan Plumbing said:


> You know Widder, I'm not sure where all this started with us "doubling up". For years RectumSeal was good enough by itself, then came some of the new super dopes and then all of the sudden we found the need to "double up".


I'll double up on 2" or bigger black iron to humor my guys who have bought into the doubling up superstitious nonsense, but that's where I draw the line.

I try to make sure we're code compliant insofar as not mixing up yellow, blue or white PTFE tapes and their applications, but I refuse to double up unless I'm just weary of hearing my guys kvetch about their old wives tales.

We did a glass blowing factory earlier in the Spring -- All of the Medium Pressure lines I ran with just Laco SlicTite held their test just fine -- All of the Low Pressure lines my guys ran after the regulators that were doubled up had to be backed out and redone.


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## rjbphd (Feb 5, 2010)

Never double doses on good pipes


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## plbgbiz (Aug 27, 2010)

If a threaded steel joint leaks when using pipe dope alone, the pipe dope was not the problem.


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## johnlewismcleod (Apr 6, 2012)

Widdershins said:


> Blue Monster PTFE on potable and hydronic systems or Laco SlicTite. Generic yellow PTFE or Laco SlicTite on gas piping.
> 
> You folks who feel the need to double up with PTFE and Dope lack confidence in your abilities.


The "double up" is to lubricate the tape so it gets deep into the threads. Tape without grease or dope is susceptible to getting hung on entry and balling up outside of the fitting.

This wasn't as much of a problem when we still had and used domestic pipe. Domestic pipe threads clean and smooth because it has uniform temper, but the import pipe we are all forced to use nowadays has hard spots throughout and makes ragged, rough threads no matter how much oil you use or how new your dies are.


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## U666A (Dec 11, 2010)

rjbphd said:


> EXPANDO is damn good stuff.. to take it apart 20 years later, a couple of whack with both hammer will loosen it up.
> You MUST follow the instructions when using it. Its comes in powder form and mixed with water only enough to do the job within time frame. I used it all the times for large bushings into boiler and with bad pipe/fittings threads.. newer can doesn't say so ( due to masa data) its recommanded for putting together on ship boilers and fittings/piping.
> By the way.. aren't we all over 50 years old and worry about someone else taking it apart 20 years later????


I dunno why it works, but the double hammer trick is effective... :thumbup:


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## U666A (Dec 11, 2010)

To the op...

If the boiler in question is for heating water, dope, then hemp, then dope. Everything else gets Master's Pro Dope, and only Master's Pro Dope.


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## Airgap (Dec 18, 2008)

I've said it before, and I'll say it again....Teflon tape, pipe dope, etc., is a lubricant for the threads. The threads make the seal....

Now, there are some thread "sealants" that work in some situations, but normal screw pipe running for me is just whatever dope I've managed to not forget or lose....

Used to do the tape then dope, but now it is very rare that I use both. Of course not tape on gas....


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## Mississippiplum (Sep 30, 2011)

Blue monster and Teflon dope- usually great white or herculees. I usually combine em- 2 wraps of tape and a dab of dope on the fitting. but in some situations like bad threads were the tape might add to much bulk not letting the fitting thread right then it's just dope.

sent from the jobsite porta-potty


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## UN1TED-WE-PLUMB (Oct 3, 2012)

Tape then dope on water. Just dope on gas

I was always a fan of the old yellow rector seal but I'm digging the blue monster dope right now. I also have been using the blue monster tape for a while and it's the sheeeet ...


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## U666A (Dec 11, 2010)

Mississippiplum said:


> Blue monster and Teflon dope- usually great white or herculees. I usually combine em- 2 wraps of tape and a dab of dope on the fitting. but in some situations like bad threads were the tape might add to much bulk not letting the fitting thread right then it's just dope.
> 
> sent from the jobsite porta-potty


On the fitting? It actually says in my codebook that no sealants nor lubricants shall be applied to female threads.


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## Gettinit (May 9, 2012)

U666A said:


> To the op...
> 
> If the boiler in question is for heating water, dope, then hemp, then dope. Everything else gets Master's Pro Dope, and only Master's Pro Dope.


Works great with SS pipes.


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## Fullmetal Frank (Jul 11, 2012)

I just dope or tape, never both.


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## U666A (Dec 11, 2010)

Gettinit said:


> Works great with SS pipes.


...

Sorry, thought I was quoting a different quote


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## BROOKLYN\PLUMB (May 21, 2010)

Water or steam I lamp wick and dope, on gas dope only on a plastic thread I Teflon.


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## Mississippiplum (Sep 30, 2011)

U666A said:


> On the fitting? It actually says in my codebook that no sealants nor lubricants shall be applied to female threads.


should have said that differently- dope and tape is only applied to male threads.

sent from the jobsite porta-potty


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## plumberdad70 (Sep 29, 2012)

i never double up but i was on a job with a guy yesterday and he wanted dope then tape, it would make more sense to me to tape then dope so you lube the tape but it was his job and i was just giving him a hand!!!!!:whistling2::whistling2:


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## deerslayer (Mar 29, 2012)

I dope then tape then dope again, then prepare the female threads with copious amounts of dope and throw a little tape in for good measure!:laughing::laughing:


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## plumberdad70 (Sep 29, 2012)

:thumbup::thumbup::laughing::laughing::jester::jester::no::no:


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## Widdershins (Feb 5, 2011)

deerslayer said:


> I dope then tape then dope again, then prepare the female threads with copious amounts of dope and throw a little tape in for good measure!:laughing::laughing:


I just sign the checks.


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