Stubborn drip

[imaddicted2u]

Help, I have this 2" pipe plug into a 90 elbow that I can't seem to stop dripping. It dripped 1/4 cup in a day.
I've recently removed an old coal boiler. There were four 2" pipes that I cut off, those all sealed fine. All but one of the pipe stubs came out without too much effort. One was very difficult though. It took lots of heat and 5 feet of pipe on my 2 foot pipe wrench to get it apart. The pipe itself twisted under the strain but it finally came out. The threads in the elbow look good. I cleaned both sides of the threads with a wire wheel and sprayed with brake cleaner to de-grease them.
First time I used a pipe joint compound called Leak Lock from Highside Chemicals Inc. but drip, drip, drip.
Next I tried 4 turns of white teflon tape but drip, drip, drip.
Then I found a roll of a thicker pink teflon tape, four turns...drip, drip, drip.
Lastly I tried 4 wraps of white teflon tape topped with a coating of the Leak Lock...drip, drip, drip. (I let it sit a few days before filling the system)
My only guess is that the elbow went oval when the pipe stub twisted.
Does anyone have a sure fire tip to keep the fitting from dripping? I'm not really concerned about ever taking it apart. It won't ever see more than 30 PSI of water pressure.

 

[SimonG]

4 wraps of ptfe will do sweet fa to something like that. Get some wraps on it and plenty of paste.

 

[cjg]

more ptfe tape,+smear the tape and the internal threads with plumbers gold clear and screw it all back up

 

[ShaunCorbs]

Try 10 wraps plus a bit of dope

 

[exedon2]

Loctite 55 wrapped on till thread almost disappears!

 

[RayW]

https://www.NoLinkingToThis/p/ferno...s7hUbCopcAr6IalyrJhoCMZcQAvD_BwE&gclsrc=aw.ds

 

[moonlight]

Hemp and jointing compound if its on heating pipework but not if on potable water.

 

[Last Plumber]

Is it appearing from the thread or is the elbow split?
Take the elbow off and put a cap on rather than keep trying it.

Whilst we are looking at that photo, not to cause alarm, just curiosity, did you remove lagging from the pipework?
It looks a bit like residue of asbestos lagging (aka pig muck) on the blurred part of the picture above the elbow. It will be the right age to have had that on it but as I say, it could be a deposit from something far less sinister.

 

[imaddicted2u]

Is it appearing from the thread or is the elbow split?
Take the elbow off and put a cap on rather than keep trying it.

Whilst we are looking at that photo, not to cause alarm, just curiosity, did you remove lagging from the pipework?
It looks a bit like residue of asbestos lagging (aka pig muck) on the blurred part of the picture above the elbow. It will be the right age to have had that on it but as I say, it could be a deposit from something far less sinister.

No, I don't think the elbow is split. I can see the water is weeping out of the threads at the 2-3 o'clock position and running down. My first consideration was to remove the elbow and get rid of it but given the troubles I had getting the pipe stub out of the elbow, I'm afraid I may run into the same problem getting the elbow off, so I'm leaving that as the last resort.
I think the elbow has an issue though. The fitting doesn't feel right when threading it in. It's tight and binds every 1/4 to 1/2 turn on the way in. I didn't think of it before but when I took the plug out when I tried teflon tape alone, the threads were clean. It seems the teflon tape is being pushed out of the threads and back. Here's a pic, does it look normal? Same thing happened when I applied tape and pipe dope but I didn't take a pic. I'll post a pic when I get around to taking it apart again. The other three 2" fittings I did with just Leak Lock pipe dope alone are not leaking at all.

I think what I'm going to do is, put a 2" to 1 1/2" bushing, with tape and dope, in the elbow. Then I can reach in and force sealant around the end of the bushing and threads inside the elbow. Then put a 1 1/2" plug in that and hopefully call it done. I thought I would like to use one of the products suggested above to seal the end but haven't been able to find the Plumbers gold or LS-X products here in Canada. Not sure if there is an equivalent here.

No, there was nothing, asbestos or otherwise, removed from the pipe.

 

[Last Plumber]

If it binds and pushes the PTFE off the thread, then there isn't a lot you can do apart from replace it. The thread on the plug is tapered and the tightening into the fitting makes the joint with the aid of compound, paste or tape etc. If it isn't round there will always be a gap somewhere between plug thread and female thread. Filling those kind of gaps with anything means you are relying on whatever is filling the gap i.e. not a true joint. This will more than likely lead to leaks now or later.
I would heat the elbow only, so it expands and undo the fitting whilst holding back on the vertical pipe. Fit a cap on the end of the pipe.
I know you'd rather avoid that but I can't see a way round it.

 

[Ben-gee]

Could try heating up the elbow, then screwing in the plug in the hope of distorting the elbow back to round when you bind on the tight spots.

 

[imaddicted2u]

If it binds and pushes the PTFE off the thread, then there isn't a lot you can do apart from replace it. The thread on the plug is tapered and the tightening into the fitting makes the joint with the aid of compound, paste or tape etc. If it isn't round there will always be a gap somewhere between plug thread and female thread. Filling those kind of gaps with anything means you are relying on whatever is filling the gap i.e. not a true joint. This will more than likely lead to leaks now or later.
I would heat the elbow only, so it expands and undo the fitting whilst holding back on the vertical pipe. Fit a cap on the end of the pipe.
I know you'd rather avoid that but I can't see a way round it.

When the oil fired boiler was installed in parallel with the coal boiler, this is how they stabbed in the fittings on the 2 supply and 2 return headers. After twisting the pipe stub in the elbow into a pretzel getting it out, I think I'd weld in the plug or bushing before messing with the elbow. I originally had a bushing and drain valve where the plug is now and would go back to that.
A friend of mine is going to borrow a 2" NPT tap from his work, maybe that will help clean up the threads and make the elbow round again. I'll heat it before running the tap in as Ben-gee suggested.
I don't need heat now and I'm retired so I have nothing but time...lol.

 

[Last Plumber]

I did think whether a tap would do any good yesterday but I am not sure it will. The fitting is malleable so if it is out of shape the tap will cut where the narrowest part is and probably make things worse by slackening the thread off too much. I may be wrong on that, it might be worth the gamble but I still think losing the elbow is the route I'd take.

If you want to try again at sealing it, I would recommend boss white and hemp. The oil in the boss white will help lubricate things and the hemp will bite in well. Smells good enough to eat too.

 

[SimonG]

The tape was wrapped onto fitting in the correct direction?

 

[imaddicted2u]

The tape was wrapped onto fitting in the correct direction?

LOL, yes, and if you look at the first pic...it's leaking with tape and dope.