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Wrenching an Old 2-inch pipe

Posted by sonofprim (My Page) on
Sun, Apr 10, 11 at 21:57

I have a 65 year old house with some galvanized waste lines. I may need to disconnect a series of fittings (or at least the end one) that wye into the closet bend. These are two-inch fittings. They are 22&1/2 and 45 degree els and close (or very short) nipples.

My concerns: Do I have any chance of twisting one of these out with a big wrench, given the age of the pipe and fittings? Am I more likely to break or crush something rather than get them to disconnect? If I try to wrench it, what size wrench should I try (I'll probably have to rent it)?

If something breaks, I'll probably have to replace the closet bend and main stack pipe, something I'd like to avoid.


Follow-Up Postings:

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RE: Wrenching an Old 2-inch pipe

I'd apply penetrating oil to the threads for a few days to try to loosen it up, and then use an 18" pipe wrench on the fitting. You may need to use a length of pipe as a handle extension on the wrench in order to develop enough torque.
If it's a fitting that you don't need to reuse, a few sharp blows can break it (it's cast iron).


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RE: Wrenching an Old 2-inch pipe

Can you just cut the lines?

A sawzall with a metal cutting blade makes short work of galvanized steel lines.

Why are you removing them?

You can abandon them in place unless you need the space for new lines.

An 18 inch wrench is just getting started on old 2 inch lines.
A pair of 24 inch wrenches (and two people) would be better.

If you do not back up the working wrench you may damage things you want to keep.


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RE: Wrenching an Old 2-inch pipe

If I cut them, then I can't hook anything up to them. The sequence is:
side-entry-wye into closet bend,
close nipple,
90 degree el (ends with good slope),
close nipple,
22 1/2 degree el (ends with uphill -- wrong way -- slope),
pipe segment I cut and joined with a fernco to new pvc.
I've found a cut-off blade in an angle grinder to be quick way to cut the steel pipes, sometimes finishing with a recip if needed to reach a back side.

Why remove them -- I have a leak at the last steel joint before the ferco. I might be able to get it to stop with epoxy, but If that fails, I'll have to twist out some of the fittings. And, if I do that, I can correct the slope problem as well. However, I can envision ways for it to go bad: 1) fitting breaks but doesn't come loose; 2) nipple or pipe segment breaks or collapses, but doesn't come loose; 3) the closet bend cracks or breaks.

So the question was am I likely to be able to put in enough force to break the joint loose without cracking a fitting or crushing a pipe? The first hint was to try penetrating oil, and if I have to try the wrenching, then I guess I'd add that to the attempt. Your suggestion about the backing wrench makes sense, but there isn't a lot of room.

Further suggestions are more than welcome.
Thanks in advance


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RE: Wrenching an Old 2-inch pipe

"If I cut them, then I can't hook anything up to them."

Just use a Fernco, no threads required.


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RE: Wrenching an Old 2-inch pipe

Heating them will make wrenching easier. Apply substantial heat, but not enough to ruin the galvanizing, apply penetrant as it cools and wrench after it is cool. If you get the old pipe out of the threads, the threads can be chased with a tap and new threaded fitting installed.


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RE: Wrenching an Old 2-inch pipe

re bus driver: heating may help, if I have to try the wrenching, I'll try that.

re brickeyee: If I cut the close nipple, there wouldn't be enough pipe length for the fernco to grip. I've got at most 1/2 inch of pipe between the ends of the two elbo's, possibly less. I wouldn't expect the fernco to be able to grip that.

Right now I've epoxied the leak. Will test tomorrow. If no leak, then I'll skip the wrenching.


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RE: Wrenching an Old 2-inch pipe

You can always cut the fitting instead of the pipe, then carefully slice into the ring left on the threads from the fitting almost to the threads on the pipe.

The ring comes off pretty easily most of the time (and you can always cut down to barely at the top of the pipe threads and them split the ring).

Often it is far easier to tear out more than you actually need to remove to get some new pipe in.


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RE: Wrenching an Old 2-inch pipe

Brickeyee: Thanks, I hadn't thought about cutting the fitting. That might work and reduce the risk. I'll see when I test it tonight if I can get away without doing anything else. Or, put more off for another 30 years.


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RE: Wrenching an Old 2-inch pipe

The house is 65 yrs old and the pipes are no doubt original to the pipe. It then stands that the pipes are without question severely corroded with lime, salts and mineral scale on the inside walls of the pipe and fittings.

Under those circumstances penetrating oil would take days to work in and it is extremely doubtful if it would do any good.

Heating the pipe is definitely out of the question. Sewer gases are primarily composed of methane and sulfur dioxide and are highly flamable, not to mention that they are explosive in high concentrations. One should never use any open flames on sewer lines.

The proper procedure for using pipe wrenches is to always use them in pairs, one to hold the pipe while the other turns the fitting or vice versa. when one attempts to turn a fitting with just one wrench there is no way to insure that the fitting won't hold and the pipe rotate creating a leak at the next joint, which is more often than not inside a wall or other equally difficult place to access.

For an old 2" pipe I would begin with two 36" pipe wrenchs and if that doesn't work I would hold the pipe with a 36" wrench and use my 48" wrench to turn the fitting.

The other optiong is to use two 2lb hammers. Hold one hammer tight against the side wall of the fitting over the threaded section and rap the opposite side of the fitting with a second 2lb hammer. Usually within two or three blows the fitting will shatter and come off the pipe. You can then clean the threads of the pipe with a wire brush and attach a new fitting.


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