Ive just finished insatlling about 70' of black pipe for an LP application. Put 25 lbs of pressure on it and of course it leaks. Ive been reading the thread on finding leaks, but once you find one how do you fix it without having to take everything apart down the line? I bought my pipe and had it cut a my local home improvement store and I think the guy did not put a taper on the cuts. Can that cause a leak? Any and all advise would be greatly appreciated. Thanks
Find and fix black pipe leaks
- Thread starter medic6940
- Start date
HoosierBuddy
Well-known member
There is no possibility that he "didn't put a taper on the threads". The pipe threading dies have the taper built right in.
What did you use for sealant on the threads? Did you go with a high quality pipe dope or teflon tape?
Be aware that if you didn't use either, every single joint will leak.
You'll need to disassemble everything and redo it properly. Personally, I prefer pipe dope over teflon tape. Leak Lock is a brand I've had a lot of success with.
Phil
rsanter
Well-known member
when it comes to LP lines, you aleays want to use pipe dope, not teflon tape
bob
bob
nate379
Banned
I have better luck with teflon tape on the **** Chinese pipe, which is pretty much all you can get these days. Use the stuff for fuel/LP, etc (it's yellow)
Any reason you are pressurizing it that much? 3-5psi should be all you need, maybe 10 psi to overkill it.
Any reason you are pressurizing it that much? 3-5psi should be all you need, maybe 10 psi to overkill it.
Last edited:
rasit
Well-known member
Same goes for pipe dope, look for the stuff that is specifically for gas lines
larry4406
Well-known member
I use Rector Seal brand dope, seals well, never used teflon tape on gas pipe. Be careful as some sealants are not approved for LP. I charged my pipe to 100 psi as I am using it for airlines.
Regarding the cutting in of a union, make sure it is accessible via an access panel if the pipe is concealed and being inspected.
I have had some of the fittings with porosity in the castings have thru-wall leaks.
Regarding the cutting in of a union, make sure it is accessible via an access panel if the pipe is concealed and being inspected.
I have had some of the fittings with porosity in the castings have thru-wall leaks.
ripsnortMN
Well-known member
I just did this a few months ago. I got all my black pipe from one of the big box stores (menards). With the pipe dope alone I could not get it to seal up. I assembled it three times and still had leaks.
Finally I went and got some of the yellow pipe tape that is specifically for ng and propane. I used the tape with the sealant that failed before and it worked.
I hear that most of the black pipe you buy from the big box stores have poor fittings and poor fit up. Thats why I had trouble with it sealing I think.
Finally I went and got some of the yellow pipe tape that is specifically for ng and propane. I used the tape with the sealant that failed before and it worked.
I hear that most of the black pipe you buy from the big box stores have poor fittings and poor fit up. Thats why I had trouble with it sealing I think.
D.J.
Well-known member
In the industry we use Tape first then dope! (Rector Seal w Teflon in the Dope can't remember the number but deems like its Number 2) Useing yhis method we rarely have a leak, one time we finished and we had a BIG leak, couldn't even get it to hold pressure, and as it turns out it was a sand void in the casting process. We found it and had to drive back round trip about twenty miles for the 3/4" cap on the drip leg, at least it was easy to get too. Reminds me of a joke. You know why oilfield workers love their jobs, Cuase the joints are 30' long and the dope comes in 5 gal buckets!
________
********* Cam
________
********* Cam
Last edited:
Torque1st
MEMBER EMERITUS
I just used Rectorseal #5 (yellow) by itself on about 8 threaded joints with Asian fittings from HD and had no leaks with NG.
Rectorseal applications chart:
http://www.rectorseal.com/chrt.htm
Rectorseal applications chart:
http://www.rectorseal.com/chrt.htm
I was taught the same by a plumber of 40-odd years when I complained about getting leaks when using tape alone. "Gas tape, then gas dope" he said. I've never had a leaky joint since.
FWIW I had all kinds of trouble threading Chinese black pipe. Even after dressing the die set and changing cutting oils the threads were still tearing. I ended up single-point threading all the pipe for my house on the lathe. MUCH better results!
Torque1st
MEMBER EMERITUS
-Dirty steel, not unusual.
All I use is Rectorseal no 5, mostly for gasoline or diesel, and air. Rarely had an issue. I see guys use tape and gasola and wonder why. I don't buy fittings at HD or Lowes only from Plumbing supply houses
nate379
Banned
Is that stuff black?
Some of the gas piping to my boiler had that stuff when I took it out to reroute. Was a royal ***** to get loose.
Some of the gas piping to my boiler had that stuff when I took it out to reroute. Was a royal ***** to get loose.
Torque1st
MEMBER EMERITUS
Rectorseal no 5 is yellow and the tube is yellow.
Shocker
Well-known member
I used yellow pipe dope with the yellow pipe tape in combo. Tape first, dope second. I haven't tested it yet, but I am feeling good about it.
The electricians, I am told, use straight threads. So the big box person could have used the wrong die.
chevelle67
Well-known member
If the Chasers in the die are not set right you can get a running thread which will never seal properly.
Threads on pipe are the same for a plumber , pipe fitter or Electrician. Couplings that Electricians would use are running threads and not tapered
Torque1st
MEMBER EMERITUS
Hard spots and cheese right next to it! Damn stuff just cracks, rips, tears, and smears...It sure had hard spots!
Not according to the Ridgid Parts Book
Huh, Electricians use a tapered thread, its code. I use the same die for conduit as I do for air line.
344.28, where conduit is threaded in the field, a standard cutting die with a 1in 16 taper
shall be used.
FPN: see ansi/ASME b.1.20.1-1983, standard for pipe threads, general purpose(inch)
Last edited:
OccupantRJ
Well-known member
I have found that a power wirebrushing around the threads of pipe whether new, or after threading, cleans up the fuzzies left by the threading die, and fits up and seals much better in general.
soj
Well-known member
I agree, clean threads can make a big difference.
I just finished up plumbing my shop for 5 infrared heaters. I used a mixture of used, made in USA pipe (removed from a house that converted from LP to total elec.) , new, made in Mexico pipe and new and used fittings. All the new fittings were from China. I cut my threads with Harbor Freight (made in China) die sets. I wire brushed EVERY thread, old or new. The male threads on a bench grinder, the female with a tapered brush on a drill. I used yellow Teflon tape only. It was labeled for use with LP and natural gas. I closed the shut-off valves at each heater location, put 10 PSI on it and went to bed. The next morning it was at 0 PSI. I suspected the ball valves. I used the valves that have the male flare made on, so I put on 5 flare caps and retested, and it held. Now I understand why the code requires a shut-off valve to be caped when not connected to an appliance.
I am convinced that cleaning all the threads really helped. All the old threads had slight rust and old, dried pipe dope in them. All the new threads had cutting fluid on them, which I cleaned with spray carb. cleaner before wire brushing. I don't know that the oil would have caused a leak, I just figured that if all I had in the joint was the tape, then the tape could do it's job.
BTW, I am not a plumber, and I do NOT play one on TV.
Also, I had some tearing of threads on the 3/4" pipe, none on the 1/2". I thought it was my cheap Harbor Freight dies, maybe it was the pipe. I don't remember if it was on the USA or Mexico pipe, could have been on both. If it was on both, I think it would be the dies. They were new, first job I have used them on, and they seemed sharp.
jp
Last edited:
Shocker
Well-known member
Agreed. I also hit all my connections inside and out with a wire brush before joining them.
I just filled my 120 gallon tank and did a leak test. Good to go to the cap inside.
I just filled my 120 gallon tank and did a leak test. Good to go to the cap inside.
72Tunaboat
Well-known member
Just go to your local hardware store and get an test gauge setup. It will thread into one of your pipe fittings. It will look something like this. It will have a Schrader valve that you can fill with air.
Thanks, that is sort of what I figured but I was not sure. I knew I could rig one up if need be but since it is more or less a required part of the job I figured there had to be a proper tool for doing this.
Shocker
Well-known member
Proper tools!?! We doan need no stinkin' proper tools!!
Kevin54
MEMBER EMERITUS
I always use pipe dope and not tape on the threads. Also when you make your runs, add a union in every so often. It really keeps from the extra work if you want to add a line or make a repair.
Regarding poor quality pipe: For you who haven't yet started -- most of the pros I know rarely buy from the big box stores. Find out where they get their stuff and you'll probably get better quality. I have never been refused at any commercial supplier if I show up knowing what I want and with cash in hand. And expect to pay a little more for it, too, but it's worth it.
Be aware tht if you are using the teflon tape or any other type tape you do not want to cover the lead thread. To demonstrate why, with tape, put a joint together and then disassemble it and you will see "threads" of the cut tape. The problem comes in when one of these "threads" enters the flow of the pipe and works its way into the gas valve, causing malfunction. It's rare, but it can happen. Leave the first thread uncovered. When using tape I hold the tape behind the thread with my left thumb. With the tape in my right hand pull the tape tight and just do a couple turns. That is all you need. You can then back it up with your choice of pipe dope.
If the guy cutting the threads is running the dies on to far, it can screw things up for you. Compare the threads to a pipe ****** for consistency. Folks like to think the joint is made "by" the pipe dope, when in fact its primary purpose is to lubricate the threads so you can more easily get more turns to make the joint.
If the guy cutting the threads is running the dies on to far, it can screw things up for you. Compare the threads to a pipe ****** for consistency. Folks like to think the joint is made "by" the pipe dope, when in fact its primary purpose is to lubricate the threads so you can more easily get more turns to make the joint.
cowboyjosh
Well-known member
- Joined
- Mar 11, 2010
- Messages
- 1,066
I still like black iron pipe more then CSST. I could give a rats *** where black iron is made and that CSST is a USA made product, i have personally witnessed lightning damaged CSST, never seen that damage with black iron, no matter its ountry of orgin.
Tracking down leaks in black iron though is a real *****.
Tracking down leaks in black iron though is a real *****.
59 wagon man
Well-known member
old school way was spoolwick and dope ran thousands of feet of gasline from 1/2" to 4" and never had a leak if we used spoolwick and dope
Milton Shaw
Well-known member
- Joined
- Feb 11, 2011
- Messages
- 4,837
The last air line I ran the only leak was in the factory cut thread on the end of the pipe,, not a leak inn any of the threads I cut. When I ran pipe for lp i cut all the factory threads off and rethreaded the pipe. No leaks held 100 lbs for 8 days.
Cast Iron Nuts
Well-known member
Wasn't sure if this has been mentioned but always using a good quality cutting oil doesn't hurt. If need be add a little bit of kerosene to it to thin it out so it flows better. Also pay attention to how long you run the threads too long of thread and the pipe starts to oval.
Frank The Plumber
Well-known member
Correct method for pipe threading:
Each diameter of pipe that is threaded has a standard length of pipe thread, run out, a 1/2" pipe would have a run out or thread overall length of roughly 5/8".
When apply a fitting to the thread, run out may be checked by doing a fitment test. Catch the thread of the fitting and the pipe, the rotation upon the complete axis should be no more or less than 2 1/2 turns ideal.
Over threading and applying more run out will flatten the thread, thus causing bottoming out into the fitting and no seal.
Improper fittings and or using non malleable fittings will affect the seal of each pipe to the thread. Only use malleable fittings.
Installation of fittings to a pipe that is still hot from cutting may cause thermal shrinkage. The hot pipe goes into the fitting expanded from the heat, is seated at high temps and tightened, the pipe cools and shrinks away from the seat.
There is a specialty Teflon tape for gas applications, the white tape degrades and leaks.
In the event that you do have a leak, you must disassemble all components up to the leak, clean and reinstall per proper methods.
It is important to clean all cutting fluids from the threads before using pipe dope.
Our favorite pipe dope is Rectorseal # 5.
Be certain not to get pipe dope into the internal surfaces of the pipe, this may cause gumming of controls within the appliance that pipe is serving, you may need a new control module if this is not followed.
You may wish to research the NPT pipe standards.
We have in several cases come across an odd type of threading that we can not get our NPT standard to apply to, we fear these may be a universal ******* thread that fits poorly between the metric thread standard and the NPT thread standard. Very cheap fittings tend to exhibit this.
Note that very few home center store guys who use the pipe threading machine have any clue as to what the run out should be. For a quick reference for those of you not in the know, a simple reference to the precut pipe ******* that are cut automated will show you how close or far your threads are to standards.
We test all gas line installations with a simple mixture of dish soap and 2 PSI air, more will damage controls or metering devices.
If you have any concerns that you may not have the skills needed to do your own gas piping please call a licensed bonded and insured professional. A gas leak is one of the most dangerous things you can have.
Hope this has been helpful.
Each diameter of pipe that is threaded has a standard length of pipe thread, run out, a 1/2" pipe would have a run out or thread overall length of roughly 5/8".
When apply a fitting to the thread, run out may be checked by doing a fitment test. Catch the thread of the fitting and the pipe, the rotation upon the complete axis should be no more or less than 2 1/2 turns ideal.
Over threading and applying more run out will flatten the thread, thus causing bottoming out into the fitting and no seal.
Improper fittings and or using non malleable fittings will affect the seal of each pipe to the thread. Only use malleable fittings.
Installation of fittings to a pipe that is still hot from cutting may cause thermal shrinkage. The hot pipe goes into the fitting expanded from the heat, is seated at high temps and tightened, the pipe cools and shrinks away from the seat.
There is a specialty Teflon tape for gas applications, the white tape degrades and leaks.
In the event that you do have a leak, you must disassemble all components up to the leak, clean and reinstall per proper methods.
It is important to clean all cutting fluids from the threads before using pipe dope.
Our favorite pipe dope is Rectorseal # 5.
Be certain not to get pipe dope into the internal surfaces of the pipe, this may cause gumming of controls within the appliance that pipe is serving, you may need a new control module if this is not followed.
You may wish to research the NPT pipe standards.
We have in several cases come across an odd type of threading that we can not get our NPT standard to apply to, we fear these may be a universal ******* thread that fits poorly between the metric thread standard and the NPT thread standard. Very cheap fittings tend to exhibit this.
Note that very few home center store guys who use the pipe threading machine have any clue as to what the run out should be. For a quick reference for those of you not in the know, a simple reference to the precut pipe ******* that are cut automated will show you how close or far your threads are to standards.
We test all gas line installations with a simple mixture of dish soap and 2 PSI air, more will damage controls or metering devices.
If you have any concerns that you may not have the skills needed to do your own gas piping please call a licensed bonded and insured professional. A gas leak is one of the most dangerous things you can have.
Hope this has been helpful.
Thank you Frank. Every one who cuts/threads/runs pipe should post this on the wall for quick reference. Part way throught your post, I thought, this guy actually knows of what he writes. I like the blue stuff for gas. For sprinkler lines, I like Permabond, not cheap but it does not wash out, and we can backout a fitting a bit for alignment.