Cut & cap off galvanized waterpipe

[Milomisha]

Hello,

Can anyone offer advice on how to cap off a 1/2" galvanized waterpipe? The pipe will be cut and not have any threads. When the water is turned back on, there will be full water pressure (60lbs/sq inch) in the pipe. I know the best way would be to replace the pipe, but its in a wall of a 100 year old apartment building and the owner doesn't want to inconvenience the tenants by performing major renovations.

Thank-you for any advice
Milomisha

 

[Herk]

So you cut it off with a saw and thread it and screw a cap on it.

And if the landlord doesn't want to renovate a 100-year-old building, the inconvenience could be a lot worse when this thing goes to pieces.

 

[Sponsor]

 

[Jadnashua]

I'd feel uneasy trying to get a compression fitting to seal. Leave enough sticking out where you can put some threads on it. Then thread the cap with some pipe dope. Haven't priced a die...maybe you could rent one.

 

[hj]

fitting

Cut and thread it is the proper way. The only other way I would be comfortable with, does not come smaller than 1".

 

[Milomisha]

Thank-you for the responses,

Cutting a new thread is an excellent idea. However, the pipe is 5/8" from a stud and 2" from a wall, so I don't know if this is possible. I could cut out a section of the stud and wall to get some room to do this. This way the demolition is contained to one apartment unit. There are already threads where I want to cap it off, but this is where the leak is, (at a 90 degree elbow) and I'm reluctant to unscrew this elbow and use a cap on the existing rusty threads, fearing it will leak again. I take it there is no magic compression fitting that is trustworthy.

Thank-you again for your responses,

Milomisha

 

[Krow]

The only suggestion that I could offer is, to unscrew the peice going in to the wall (hopefully it will come out of the fitting without breaking it off). Once that is done, buy a threaded nipple and cap(the proper length nipple) , thread dope or teflone the threads and screw it into the fitting buy feel.
If it breaks inside the wall, you will need to open the wall, and remove the fitting, and cap it inside the wall.

 

[adb]

There are already threads where I want to cap it off, but this is where the leak is, (at a 90 degree elbow) and I'm reluctant to unscrew this elbow and use a cap on the existing rusty threads, fearing it will leak again. I take it there is no magic compression fitting that is trustworthy.

If getting a die around the pipe to re-thread it is not an option, I would feel vastly more comfortable applying some heat, removing the existing 90 (make sure to use another pipe wrench on the other side so you do not loosen something else upstream!), and cleaning up the threads with a wire brush than trying to jury-rig anything else. With some rectorseal and a cap I suspect everything will turn out just fine. If you like tape, use two full spiral wraps of the pink waterline stuff.

I would also back-up the existing pipe with a second pipe wrench while tightening the cap to avoid disturbing any upstream joints. Depending on what they were sealed with long ago, unnecessary movement could cause new unpleasantries.

Even if there was a magic compression fitting, it would not be legit inside the wall.

 

[Milomisha]

Thank-you everyone for the help. This is a great forum,
Milomisha