Sealing Black Pipe??

billygoat22

Sometimes cranking down too hard can "strech" the fitting and it will leak. I think too, some brands have poor tolerance on them and don't fit together like they should, Sometimes with a problem joint I use dope, them a wrap of teflon, then some more dope and that will hold.

RonHa

Black pipe leaking

Hello Everyone,

I'm in the middle of replacing some haphazardly installed undersized primary piping on my boiler. I have FHW baseboard throughout the house on 4 zones. The existing 4 circulators are installed on various pieces of 1/2" nipples and crooked unproffessional looking returns. I decided to install new 1 1/4 black pipe manifolds and nice straight returns. I decided it would be wise to pressure test all the new piping before "cutting it in". I sealed all joints with teflon tape and no matter how tight or not so tight I make the joints, I still have several T's and elbows that show leaks when I soap up the connections. I capped the ends and pumped 30psi of air into the assembly. No matter how much I crank down on 24" pipe wrenches I still have leakers. I have done plenty of gas piping using blue blocker to seal the threads and never had any leaks. Any advice that you guys can give me would be greatly appreciated. I've never had this much trouble before. Thanks for your help.

Ron

Jeremy

Thread Sealant

I use "Rectorseal #5 SPECIAL" or "Keytite" thread sealant and have great results. Hope you get them fixed.
Jeremy

RonHa

Hello Jeremy,

Do you think it's the teflon tape that's not working?? I have taken apart some of the leakers and I'd swear they were cranked so tight that the nipples practically bottomed in the T's. Reassembled with more tape after cleaning and inspecting the threads and it still bubbles slightly when soaped. This has never happened to me before. How tight or how much "cranking" do you use when assembling your piping?? Thanks for your help

Ron

Unknown

We use both Teflon and Rectorseal

Just 2 wraps on the nipples with some Teflon , paint some Rectorseal on it , and coat the inner threads of the 1 1/4 with the sealant , and the joints would hold if they were hand tight - well at least I think they would . Just using Teflon alone on the bigger sizes can give you some leaks . The only reason we like to use Teflon is because its a breeze to take apart the fitting in the future - if needs be . Good luck .

Tom_12

I use teflon and Megaloc pipe seal for water. Just Megaloc as an oil dope it works great. Never had any problems, it stays soft and comes apart if you have to re do any thing.

Dana Zaichkin_3

Dope-tape-dope

This has worked pretty well for me on H2O piping too. I've had good results with Rectorseal #5 alone on gas - sometimes I like to rub a little with my finger inside the fitting just so some lubrication gets pushed ahead of the nipple. I try to keep in mind that dope is primarialy a lubricant that allows the metal threads to seal tightly - vs being a sealant.

Tom M.

Megalok

I also use teflon with Megalok but I've had some problems on oil. It works great on oil lines, pumps and piping but I've had a few tanks that seep at the 2" connection on top of the tank when it is filled. This has happened on 2 or 3 jobs including my own house. All 3-4 years old. I'm trying rectorseal Tru-Blu but it's too soon to tell if it's helped.

steve_6

we've used

Rectorseal, Kling, Rectorseal and works well, especially on larger pipe diameters. Kling or roller gauze is a bandaging material available at your drug store. Wrap it like your applying teflon

steve_6

thorn in my side

what do you guys do with leaking unions? I've tightened , retightened, removed, examined mating surfaces, (smooth and in good shape) doped retightened , and still leaking. I think these are Ward fittings, "new".Are their better fittings or would flanges work better?

paul lessard_3

combine the two?

In the same store walk up and say"Yea howbout Rectokling"
no really,sounds good...o.k. It's sat A.M get a jump on mon or study for future?

paul lessard_3

combine the two?

In the same store walk up and say"Yea howbout Rectokling"
no really,sounds good...o.k. It's sat A.M get a jump on mon or study for future?

Earthfire

threads

Just did a 1 1/2" gas line in black iron .Ward mallable fittings, Wheatland pipe, Rectorseal 5. About 50 threaded connections with tee's,el's,valves,unions,dripp legs, etc. Mostly hand threaded and no leaks at 2hr 60psi test. had a boiler job a couple of weeks ago, supply house snuck in some CHINA fittings and every one sprinklered. beware generic fittings

Big Ed

Unions Seat

Steve, dab a little plumber grease on the union's seat..It will fill up the imperfections....If it's a old union you need to clean it first . This will help

Ray M_2

leak

I like to use teflon and dope,but have had leaks due to bad fittings.The product that can save you is Leak Lock made by high side chemicals.
LOL Ray M

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Tony Conner

There Are All Kinds...

...of junk fittings, pipe & nipples out there. All grades and makes, and its VERY frustrating. I think the manufacturers have been beaten up on price so badly, for so long, that everything just gets cheaper and nastier all the time. If you make a better fitting, but nobody will buy it because it costs more, you can either start making what will sell, or get out of that business. If we haven't actually hit bottom on the pipe and fitting quality slide, I think we can see it from here.

Tony Conner

I've Even Tried...

...using 3000# forged steel unions in a lot of installations. They leak too, especially the 2" ones. So on a recent job installing a 1" steam PRV, we used 150# screwed flanges. The actual gaskets don't leak, but the nipple screwed into the flange (on the low pressure side, no less) leaks. We can't use teflon tape, or anything "teflon" at all in this plant. That eliminates a LOT of pipe dopes. We've recently tried the Megaloc stuff that's supposed to be good to 400*F, but it sure "looks cooked" after a day or so exposed to 350*F steam. It goes from blue to beige in short order. It's Megaloc on a sch 80 A106B factory nipple that's screwed into the back side of this flange that's leaking. And I cranked it together in the tristand before it went up. It's just maddening.

Mad Dog

Hey bro!@!!!! there ain't a leak in the world I ain't been able

with lampwick and black permatex. Mad Dog

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Tony Conner

I Used To...

...think that pipe dope was primarily a lubricant, and that the actual sealing was done by the threads themselves, but not necessarily. I found a neat little book on hydraulic systems, and since they often deal with liquid pressures that can run several thousand PSI, this is what they say:

"Due to the clearance between the root of the internal thread, and the crest of the mating external thread, (as shown in illustration #80) there will be a spiral clearance along the length of the thread; therefore a sealant must be used on NPT threads. The sealant should be applied to the external threads only, avoiding the first one or two threads, to reduce the possibility of system contamination. The sealant will also act as a lubricant, and reduce the chance of galling."

The illustration #80 shows two mated threads - sawtooth pattern - with the tips not coming QUITE to a point, but flat.

"A variation of the NPT thread that is used for hydraulic purposes is the Dryseal ANSI Standard Taper Pipe Thread (NPTF). This thread has the same form and dimensions as the NPT thread, except that the truncation of the crests and roots is changed to ensure that the spiral clearance around the thread is eliminated. (This thread is also referred to as the National Pipe Tapered Thread For Fuels.) The interference at the crest and root of the mating parts of this thread eliminates the need for a sealant to seal any clearances. Be aware that assembling any thread system without lubrication can lead to galling, especially with materials such as stainless steel or other nickel alloys. A thread sealant should be used with this thread for anti-galling purposes. Note that special taps and dies are required for making this type of thread. Unless specially marked, NPTF threads are not easily distinguishable from NPT threads."

This is from "IPT's Industrial Hydraulics Handbook", by James A. Archer.

RonHa

Thanks to all

Hello Everyone,

The rectorseal seems to have cured my leaks. Disassembled,cleaned and reassembled with rectorseal, no air bubbles and holds pressure while testing. In a few weeks I'll reassemble everything in the boiler room and hope it holds water:) Never had these problems working with the smaller 3/4 and 1/2 pipe, tape seemed to work fine on those. NOW if I could get these Stinkin Unions to seal I'd be a happy camper:( Thanks again to everyone for your help.

Ron

John Abbott

Unions...

someone advised you to lubricate the mating surfaces with heatproof grease and they were right coat both the mating surfaces and union threads and other than damaged surfaces you should have no leaks.

John

David Sutton

I have found that..

on the small fittings i use just teflon tape and dope i put a small bead on the first thread and let the fitting push the dope up the thread.
on the bigger threads 2"- 6" i use wicking, this is a good cotton strand kite string. i find this works good and i never put a pipe wrench on the pipe it self cause you can worp it or oval it as you spin it in this will always cause a leak good luck hope this helps ...David Sutton

Big Ed

I agree with Mad Dog \"If you don't want it to leak use the wick

But I use Magaloc and lampwick(quickwick)... I agree Permatex would be better (but the mess ! ). I went full circle and almost back to old way .I remember using Permatex at my begining .... What is great about using the wick besides lack of leaks is the fact of a more rigid pipework ...When your building a manifold with teflon the work is moving all over the place by the weight alone..Also , wick is a must on brass and adapters.Ahh the ringing in my ear by the Deadmen ,,,in one ear ,"If you don't want it to leak use lamp wick" And in my other ear "if it slips clean your teeth".....your stilson's teeth that is......

Dana Zaichkin_4

Hum...

Makes me want to experiment with a little waxed mint dental floss - or maybe the gore-tex stuff.

DZ

Mike T., Swampeast MO

Hercules \"real-tuff\" teflon paste

Maybe I'm just lucky (or my supplier only carries good fittings) but I get so few leaks using it--both new and re-made black iron joints--that it can be considered almost perfect.

It lubricates VERY well (you need less torque to begin with) and forms a NON-HARDENING seal.

When transitioning from iron to copper I've found this seems to work best: real-tuff on the FEMALE threads and liberal teflon tape on the male. I prefer female iron to copper male.

Brian_19

Loctite pst

I use Loctite PST thread sealant. I have never had a leak
using this product. I have had leaks using mega lock. Threads would not leak on initial installation, but would leak several months later. PST stays soft does not get hard
over time and heat.

Andy Morgan_2

Real tuff

This stuff is great. I use it on everything up to 2".Very, very few leaks, even on cheap fittings. Used to use Herc. blue Block, but was very messy.

Andy Morgan

Tony Conner

As Long As The Temps Are...

...under 300*F, Locktite stuff is great. Once you get into higher pressure/temperature steam, it runs out of gas. The same thing happens to lampwick, hemp, etc. It's fine on water, or compressed air, maybe low pressure steam - but high temperature service just cooks it to death. I've found the same thing with rubber gasket material. The literature SAYS it's OK for temps to 250*F. Maybe on water, or compressed air, but I've found steam at any pressure (even a few PSI) will just dry it right out to the point that it cracks and leaks.