Any lubricant for undoing galvanized pipe?

[newbury]

I've a 50 year old bathroom I'm working on.

I need to move the water shut off valve over about 4" so it does not hit the divider in the new vanity. The vanity has about 3" of "clearance" from the wall.

The valve is connected to a short (about 4") piece of galvanized SCREW IN connecting through the wall and screwing in to what looks like a galvanized or brass tee.

My "plan" is to come out with a shorter piece of galvanized, do a 90 degree, run it for a about 4" and put in a new shutoff valve.

I'm pretty sure it's been setting about 50 years. I anticipate it's stuck. Besides using good pipe wrenches is there anything like PB blaster or Kroil for plumbing I could spray on to "loosen" it up?

I don't want to use a torch too heat it up because of all the tinder dry 50 year old framing. And I don't want to wet the framing down for fear of mold when I close up the holes I'm making.

 

[davesl708]

Well with 50 year old pipes in my experience if they don't come loose they break off. I would keep an extractor handy and tap to clean up the threads.

 

[ultrarunner]

Any way to neatly notch around it?

Unless I can support the elbow or T my experience is 50/50 as to damage when taking apart.

Sometime the nipple actually crushes.

 

[Raspy]

You won't be able to get any lube in those threads because they have pipe dope on them. You'll probably smash the pipe a bit before it comes out with the force of the wrenches because steel pipe is malleable. Just use the biggest wrenches you can get on the pipe and the fitting it's screwed into and use opposing force. Cheater pipes on the wrenches often help. It will come out unless weakened by rust. Go back together with brass fittings.

 

[2458n]

M y house was built during World War II. No copper pipes in the house either. Hard water had choked the pipes down to a pencil sized hole. I would change the inside of the cabinet if possible.

 

[ozley]

Think positive go slow and it will come right out.

 

[Threepoint]

Well with 50 year old pipes in my experience if they don't come loose they break off. I would keep an extractor handy and tap to clean up the threads.

Agree with this!

 

[TomSeller]

I did quite a bit of rework on my 66 year old galvanized piped house. The original installer used massive amounts of pipe dope so they always turned off. Replaced sections of the house with copper as I went, however. Eventually did the whole house. As was mentioned in a prior post, lines this old were pretty choked down.

 

[Raspy]

There are a lot of kinds of pipe dope. Some kinds harden like a rock and others stay like grease. Some of it is more like glue and almost eliminates the possibility of taking it apart decades later.

It's always good to go to copper when replacing old iron pipes. Simply screw in a brass nipple as a transition piece to go from steel to copper and all the galvanic problems of copper to steel go away. A dielectric union accomplishes this too, but is not as good.

 

[ultrarunner]

I've replaced a lot of galvanized when the opportunity presented itself.

Most of it dates from 1922 and if it was not for remodeling... it would all still be there.

Inside is clean as a whistle... going on 95 years!