Galvanized Pipe Disassembly question

[JoeTheStack]

The plumbing in our house is from 1944, it is galvanized steel or iron pipe, both the supply and the drains. It is in pretty good shape for its age. However, I am rebuilding the shower and I need to get the shower drain pipe out of the way. I will probably replace the supply as well.

Can I disassemble this type of plumbing with pipe wrenches? It is pretty old, kind of rusty, and the joints don't look like they are going to turn. Or do I have to put a metal blade on a saws-all and cut the sections to be removed?

As to the supply pipes, I am going to replace the shutoff valve before I do anything else.

 

[DFBonnett]

I had some 1 1/2" galvanized that needed replacing and some wouldn't budge. Using a torch on those fittings helped a lot.

 

[speedbump]

If you can hammer the couplings or union nuts first, all the way around they should come apart. Don't be afraid to smack them hard.

The Sawsall might be faster though.

 

[phishfood]

I am with speedbump on this one. Repeatedly wacking the outside of a joint with a decent sized hammer is a good method of breaking a fitting loose.

That does chance breaking rust inside of the piping loose, potentially causing leaks or blockages, which a torch wouldn't do, but a torch brings with it a danger of fire. And, considering it is 70 year old pipe that rusts, I would replace every piece of it you can get to.

 

[JoeTheStack]

I am with speedbump on this one. Repeatedly wacking the outside of a joint with a decent sized hammer is a good method of breaking a fitting loose.

That does chance breaking rust inside of the piping loose, potentially causing leaks or blockages, which a torch wouldn't do, but a torch brings with it a danger of fire. And, considering it is 70 year old pipe that rusts, I would replace every piece of it you can get to.

That is another question on my mind. From your replies, using a torch or using a hammer are but two methods that have been applied to removal of the old piping. And a saws-all is a third method. The objective in all three cases is to remove the old piping, right? The objective is not to remove the old piping, then reassemble it, right? It is assumed that the old piping will be replaced by new piping, right? So how much of the old piping should I replace? All of it that is accessible at this time? I think that is the answer, but I am asking.

The other reason I was asking was because if I remove a portion of the old piping, and replace it with new piping, then there will be places where I must join new piping to old, and I am already aware of the fittings available for that purpose, but obviously some places would be easier to connect to than others. It seems like it would be a good idea to bear that in mind when disconnecting things. I know you agree but I am eager to hear your comments.

 

[speedbump]

With galvanized piping, you are going to have either male or female threads to reconnect to. Every type of pipe has adaptors that will convert to other types of pipe.

 

[kreemoweet]

I personally have seen many, many tens of thousands of dollars wasted by folks who thought they could get just a little more use out of old
galvanized supply and drain piping, but ended up instead destroying and redoing much work, and water damage expense on top of that. Any 70-year old
steel pipe is LONG past due for replacement - all of it. If circumstances compel a stopping point, then always give yourself a fallback. Never assume you
can unscrew a pipe/fitting and reuse the threads. With drain piping that old, be on the lookout for leaded joints, which are next to impossible to deal
with using modern plumbing devices. Do not automatically write off cutting steel pipe by hand, using a wheeled pipe cutter if there's room, or a
hacksaw blade: it's far less likely to cause damage or blockage. The stub is usually easily connected to using a banded "rubber" coupling.

 

[Levine]

You may be able to to take the piping apart with a wrench, however when you work on old piping like you have it is best to cut it out with the metal blade. Cutting it out helps to eliminate "downstream" leaks in areas you are not replacing. This is because when you use wrenches you put torque and stress on the whole piping system (something you don't want to do on older systems!). You will save yourself a lot of headaches by cutting it out.