Capping a live water line

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drembedded

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I need to cap an old 3/4" black pipe water supply line but there is no way to shut off the line. Why there isn't a shutoff valve is a whole other story!

This supply line was the original water source to our house and we've since switched to a different source. The old line is already capped off but I need to remove 30 feet of this old line. The line was burried and is somewhat rusted.

I thought about cutting back just before a union then unthreading the remaining stub from the union and putting in a valve or a plug/cap. My concern is that the pipe may be so rusty that this may not work and I'll be left with a free flowing line.

As a backup, can I pinch the line? Is there a special pinching tool? I'm open to just about any ideas!

Thanks.
 

hj

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WHY would you even consider leaving a "black steel water line" in an active state? The ONLY proper way to do it would be to disconnect it at the source, because it will ALWAYS continue to rust out and leak as long as there is water in the pipe.
 

drembedded

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Was looking for help and not criticism :-( Agreed that there is the "proper way" but there is also the "I gotta get something done now way".

But since your post asks "WHY", I'll let you know a bit more about our water situation. We're on a private water system which was put in by the original ranchers back in '49. For the mains in our system, they used surplus water line from WWII that was meant to be used to transfer fluids from a beachhead inland. Needless to say that wasn't the "proper way" to develop a water system. For the laterals they used black pipe and buried it without any protection like wrapping it. To make matters worse they really didn't keep good records about what was where and on whose land it was, nor where shutoff valves (is they even used any) were located. Sometimes I wish I lived an a newer housing development...

So with that said, I'd entertain any ideas on how to resolve this issue with a short term solution :)

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Smooky

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You can combine a compression fitting such as a dresser coupling with a valve. Then cut the water pipe off. Slide one end of the compression coupling onto the pipe, with the cut-off valve open. Tighten the compression coupling onto the pipe and then close the valve.
 

Cacher_Chick

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Some plumbers have a device that will freeze the water in a section of pipe to prevent flow while the piping is being repaired.
 

Smooky

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I have also seen ford pack joint couplings used for this type of repair. (Google it.) They can be combined with a shutoff valve easily. These couplings are often used to connect water meters to the city supply.
 

drembedded

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Smooky, the Ford Pack Joint Couplings looks like the easiest solution. My only concern would be whether the compression fitting would be able to seat well against the corroded pipe.

Jimbo, that Jormer Valve looks sweet but it looks like it has expensive!

cacher_chick: freezing the line would make putting in the compression fitting much easier. Wonder if Home Depot rents those ;-)
 
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Gary Swart

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I sure hope you realize that whatever you do now is just a stop-gap fix. Sooner or later, add more likely sooner, you will have to get rid of that black iron and get your system up to par.
 

hj

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The realistic problem with what you want to do, is that ANY black steel pipe will be heavily corroded on its exterior. The rust will make it BIGGER than a standard pipe, and when the rust is chipped off it will be both smaller and pitted, making ANY compression connection IFFY as far as not leaking, and also making it impossible to rethread the cut off portion. There might be a way to accomplish the task, but we would have to see the pipe's condition first.
 

Jimbo

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Smooky, the Ford Pack Joint Couplings looks like the easiest solution. My only concern would be whether the compression fitting would be able to seat well against the corroded pipe.

Jimbo, that Jormer Valve looks sweet but it looks like it has expensive!

cacher_chick: freezing the line would make putting in the compression fitting much easier. Wonder if Home Depot rents those ;-)
The JOMAR will set you back a c-note and a half, and even that may have difficulty on a heavily pitted pipe.

This may a case where you have been given the best possible advice right from the get-go, but you will persist in trying to find a "work around" no matter what the cost or consequences.
 

Ballvalve

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I hate to tell you guys, but if its from 1946 and mostly holding water, its DUCTILE IRON. Which outlasts any galvanized.
 

hj

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"3/4 inch" Ductile iron? In '46 we WERE using "regular" steel pipe, black AND galvanized. Black ductile iron will outlast some galvanized but it is NOT an "eternal" metal. Acually there is NO WAY to tell what can be done with it until it is exposed to see its condition.
 

Ballvalve

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If its black pipe you can shut it off with a block of iron and a sledgehammer and fold it over. Have a nice shower. Ductile is unusual in 3/4" but you never know what went on with army surplus after the war. Ductile would likely break with a hammer.
 

hj

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"Ductile" means it is "malleable" and would NOT break. Most "army construction" jobs, especially housing, were designed to last 10 years, or until the war was over, so they did NOT worry about using materials with any kind of longevity. It was all "quick and dirty".
 

Ballvalve

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Actually, ductile iron is closer to cast iron in relation to black pipe and retains some brittle qualities. I know, I have cracked larger sizes.

http://en.wikipedia.org/wiki/Ductile_iron_pipe

Some of that quick and dirty work during the war had standards far above the debri hitting our shores now.

Malleable iron is pretty much reserved for castings that are to be machined. It indeed can take hammer blows.
 
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Jadnashua

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Bottom line...iron rusts and will not last forever when used as this situation has it installed. Anything you do with it is suspect with the age and current condition of it. You'd be far better off trying to decommission it or cap it off way back at a source that can be monitored more easily. Anything you do with it somewhere in the middle is risky. It's one of those pay me now or pay me later situations...
 
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