Leaky black iron joints

Johnybcold

Well I installed a new gas boiler it was a completely new install when I fired it up I had a bunch of leaks on my black iron joints I had used a white joint compound, so I took them apart and someone told me to use a product by rectorseal called trublue, so I redid everything and really tighted it, it was fine for 4 weeks but today I found a drip and a few other joints have alittle water. Any advice would be great is there any reason to use threaded pipe vs cooper, I am sick of playing with this and I am thinking I should just do it in copper

JUGHNE

What part of the world did the nipples and fittings come from?

Johnybcold

Probaly China seeing I got them at HD, my system is hot water to baseboards I am thinking I am going to redo most if it in copper

Eric_32

What size pipe are we talking about and what size pipe wrench are you using?

Johnybcold

The pipe is 1" & 1.5" I can double check the wrenchs when I get home they are probably 16"_18" long, anything I ever did in copper has never leaked can I just redo it in copper?

lchmb

you could use tape and dope to redo the fittings but by the sounds of it I would be doing copper...

Tinman

Teflon tape with Teflon dope and proper tightening should do the trick on a hot water boiler with 2" pipe and under every time.

ChrisJ

3 wraps of blue monster tape + a thin coating of Megaloc dope. For a 1 1/2" pipe Id be using two 24" wrenches my self and 18" for 1" pipe but don't go crazy with them.

Tighten until you feel the threads start to bind. Bind means it goes from fairly constant to getting super hard really quick.

This is the method I use and I don't have leaks even at 120 PSI. Working with threaded joints is without a doubt an art and takes a lot of practice. I also never use Chinese fittings unless I have absolutely no choice.

Is this a steam boiler install?

MarkInfo

I've just joined this group in search of an answer for the same problem. I've installed countless boilers in the past 25 years using black iron pipe as my near boiler piping. Teflon tape and TrueBlue for my connections. Thirteen months ago I installed a five zone "moose antler" piping system. Three zones are base board and two zones are under floor oxygen barrier pex tubing. See first two pictures. I received a call the other day from customer that all the fittings seemed to be leaking and rusting away. See last two pictures. I had to tear the entire manifold out... The SLK fitting where made in China and I have come to the conclusion that I received a bad batch of fittings. Anyone have any other explanation??

JUGHNE

I wrap the tape and apply Megaloc as ChrisJ mentioned. I try to use USA fittings but end up with import nipples. My twisted logic is that you can over tighten the cheap nipple into the better fitting without fear of stretching or cracking the fitting hub.

hvacfreak2

I used the opposite , I used Megalock tape and Blue Monster dope. The Blue Monster dope is white , go figure.

ChrisJ

I've heard of a few guys using black RTV on threaded joints with good success as well.

I think Gerry Gill tried it on his own system.

MarkInfo

My piping was leak free for a while. I went back a few times after start up to check temperatures and fine tune mixing valves and no leaks.

jonny88

On the bull of one of your tees the inside looks fine.13 months is not a long time.Would love to know the answer and obviously there is no drips form packing nuts on valves above etc.Thats really bad,bet you were pissed having to go back.How does the inside of nipples look.

MarkInfo

I am pissed! Would love to know why this happened... The inside of the nipples look fine!!! I need to decide fast to reinstall with black or change to copper to get the heat back on.

SWEI

hvacfreak2 said:

The Blue Monster dope is white , go figure.

I called them up and asked about that the other day. There actually is a "blue" Blue Monster dope without Teflon. The one with Teflon in it is white.

Robert_25

A few years ago I struggled with some leaks on black iron fittings in my own house. I was using Gasoila soft set pipe dope, which had never given me trouble before. It was likely a quality issue with the fittings, but I was trying to make it work. The man at the supply house suggested I try a few wraps of teflon tape and GRRIP pipe dope. I took his advice, and everything has been water tight ever since. If you have never used GRRIP, make sure you have some gloves handy.

ChrisJ

Applying dope to the female threads?
I've never done this? Seems like most of it would just be pushed into the fitting. I wipe dope on with a brush into the threads on the male side and then wipe excess off across the threads with my fingers. I'll also use my finger to make sure the threads are fairly full of dope evenly and I try to keep dope out of the threads I know will be exposed. I've found I can seal pipes with very little dope but I make sure I get it into the crevices of the threads on the male, I leave the female side bare.

ChrisJ

Hatterasguy said:

If you do not apply any dope to the female threads, you leave a massive path along the major diameter of the female threads. The only thing that saves you is the tape (since you utilize both). The dope on the major diameter of the male thread is absolutely insufficient to seal this path.

I do get a bit of "push" on some of the dope and it does appear slightly in the interior of the fitting.

The key is to use as little as possible but still get it to the base of the threads.

No tape on any of my gas pipes and they were all tested for weeks at 40 PSI. I've also done quite a few lines at work for air @ 120 PSI and no leaks.

Honestly I bet with good threads on the nipple and fitting you could use motor oil and get a sealed joint if torqued properly.

What do all of the professionals say? When using dope do you apply it to the female fitting too?

ChrisJ

Hatterasguy said:

I think you need to define "good threads".

By definition, the best NPT thread in the world always leaves a small clearance above the major diameter and below the minor diameter.

Something has to fill this space if you want to ensure no leaks.

If you are just doping the male thread, you're quite fortunate that the dope makes it to the gap above the major diameter and seals it.

My belief is that too many rely on this fortunate event and are sometimes disappointed.

Also depends on who you ask.
I never got a clear answer from anyone, or any website or book on what pipe dope actually does. Many say it only lubricates allowing you to deform the threads to make a seal. Others say it fills in the void you speak of.

MarkInfo

25 years using teflon and dope on the male threads only, never had a problem until now. Is it safe to say I received a bad batch of fittings?

Tinman

Here's another couple thing I always do -
I always use cast iron fittings on boilers if I'm using screwed pipe. They expand and contract a lot less than black iron fittings do.
I've never had the need to dope female threads. I'm guessing I never will.
Doing it this way even allows me to "back up" a fitting with no worries of a leak.
With your long history of wrenching, I think you must've got some bad fittings.

hot_rod

NPT threads are designed to seal on the flanks of the thread, but there is still a sprial path for a potential leak, they need some sort of sealant to seal properly.

There is a NPTF "National Pipe Taper Fuel" aka DrySeal threads. It is used in the hydraulic industry where they do not allow any "dope" inside the system. The crest and root are designed to be an interference, they flatten down, somewhat like a flare fitting, to eliminate the spiral leak path in a standard NPT.

Caleffi still runs some NPTF threads, but you need both male and female NPTF to get the benefit.

jonny88

If you are real concerned wick and dope.I see on these pics the outside is rusted real bad could it be a humidity factor or something on those lines.He has been 25 yrs doing it so knows how to screw pipe together.Whats attacking the pipe.

ChrisJ

jonny88 said:

If you are real concerned wick and dope.I see on these pics the outside is rusted real bad could it be a humidity factor or something on those lines.He has been 25 yrs doing it so knows how to screw pipe together.Whats attacking the pipe.

Doesn't PTFE tape work just as good as wick, but never rotts?

hot_rod

But not too much tape or that can prevent the fitting from making up properly. I like the new, thicker 3 wrap tapes. They stay on the threads better and two to three wraps is all you need.

Start the tape two threads back so you don't end up with shards of tape inside the system.

Here is some really good thread info from a recent Viega Voice magazine.

http://www.viega.us/6440.htm

jonny88

Good article pity Viega goes out of their way not to thread.

ChrisJ

jonny88 said:

Good article pity Viega goes out of their way not to thread.

Made this meme after using my 65R-TC a few times.

MarkInfo

I have no choice but to replace the manifold using copper. I'm afraid to redo it with black pipe. The basement is very humid!?!? Two crawl spaces with dirt and no moisture barrier. Rain water leaks down the front wall. Not sure if that caused all the fittings to rust. All the nipples are fine. There's a lot of black gas piping in the basement, some fittings and nipples have rust and some don't? I'm baffled!

Sal Santamaura

Is there any manufacturer still making threaded black pipe in the US today? If so, how can one ensure that a contractor will quote to use it when bidding on new construction (and actually do so when performing the installation)?

Tinman

Anvil maybe? Ward?

hot_rod

There are some plants still manufacturing steel pipe in the US. I'm not sure it is so common on the suppliers shelves, however.

There are some businesses and churches that insist on Made in the USA products, I've worked with wholesalers that inventoried both domestic and import PVF .

Some of the big name fitting and valve manufacturers offer domestic and import product lines. Although the Buy America act allows a certain % to be imported product.

ChrisJ

Stephen Minnich said:

Anvil maybe? Ward?

I think he was specifically talking about pipe, not fittings.
I don't think Anvil or Ward make pipe but I could be completely wrong.

I know I was able to buy a length of US made 1 1/4" from General Plumbing Supply a while back. Our small local supply near my house only has Chinese junk and we all know what the big box stores have.

Tinman

@ChrisJ - Gotcha
I know that when I order black iron pipe at my main supply house, I have to specify that I want domestic. And they do stock it. There's a price difference but I just pass that along. It's worth it for everyone involved.
Porter Pipe and Supply - the best supply house I've had the pleasure of doing business with in my career.
From soup to nuts, they've got it.

hot_rod

I like this Wheatland brand. I used their lighter schedule sprinkler pipe on my solar thermal array. A bit larger ID, nicer outer coating, and it threads fine, limited sized, however.

Maybe their schedule 40 is US made also?

jonny88

What do you guys think about humidity and rain water.He said gas pipe is rusted also

Fred

Markinfo's first set of pictures certainly suggest leaks at the joint/threads. His second set, which I assume are at different locations are clearly not joint leaks but most likely a very light coat of surface oxidation, likely from a bit of humidity but not anything I'd consider abnormal.

Abracadabra

pretty sure wheatland manufactures iron pipe in wheatland, pennsylvania

Dave0176

Abracadabra said:

pretty sure wheatland manufactures iron pipe in wheatland, pennsylvania

Exactly. I use Ward or Anvil cast iron fittings, malleable on gas, I'll go for Anvil nipples (expensive) or the Chinese nipples as their not that bad. For piping it's all Wheatland USA. IMO Anvil makes the best unions, their beefy.

MarkInfo

The second set of pictures were from the same manifold. I was going to keep that part of the manifold and replace the BAD fittings only..Then I decided I'd better not take a chance and have the other fittings fail in time

unclejohn

Markinfo; On one picture I see at least 5 threads. I use tape and then dope and tighten too two threads showing and I have no leaks.