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    I cracked my cast iron pipe.

    Asked Jul 8, 2007, 08:52 AM 5 Answers
    Well, I've gone an' done it now...

    I'm tapping into a 4" CI waste pipe that runs outside my house parallel to the foundation, trying to add a Combo-Wye to a new stack inside the house.

    I want to use all cast-iron for the underground/through-foundation section because i feel it's stronger, and with cast iron the code does not require me to install a sleeve through the foundation. Not that this is relevant, i would have had to cut the existing CI pipe to install PVC too.

    Anyhow, i have a (large, Rigid brand, rented) snap cutter and practiced with it on the new 3" CI pipe I'm installing. Worked like a charm, made a pretty nice cut very easily.

    However, on the old pipe in the ground (installed 1969, probably), disaster!!

    I did everything the same, as far as I can tell... but the pipe just cracked right at the top, which of course was where the ratchet part of the snap cutter was.

    Of secondary concern is the fact that there's standing water in the pipe... I don't like that one bit either. Nothing has drained into this pipe for weeks, currently it only services a guest bathroom that I've locked.

    So. The questions...

    1) Why did this happen? Is older pipe prone to this? There was some concrete-like material stuck to the upper side of the pipe, which I chipped off as best I could so the fernco couplers could seal.

    2) Would I be better off using a sawzall for the next cut(s)? What kind of blade? Fast or slow? Cutting oil?

    3) I now have to cut back and replace a part of the existing pipe. What is the minimum size? Is it bad to have two ferncos right next to each other, with the small patch piece in between?

    4) And finally... how bad is this standing water issue? This stack currently services a guest bath, which we've used plenty, and never have we had a problem with it... This part of the line IS pretty far from the septic tank, probably 50 or 60 feet, and around a corner.


    Here's the damage:

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    5 Answers
    Ken 297's Avatar
    Ken 297 Posts: 112, Reputation: 24
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    #2

    Jul 8, 2007, 09:46 AM
    I have had cast pipe break lots of times with snap cutters. I never know why it cracks like this maybe just a weak spot in the pipe.
    I would just move down an inch or two and try again. A Sawzall works fine if you get a good steel blade. I usually just use a hack saw. Five minutes with a hacksaw will save running out to get a sawzall. Cutting oil isn't required.
    It doesn't matter how close the fernco couplings are together. Just give yourself enough room to work.
    The standing water could be serious if the pipe has backfall or it could be nothing if it just has a blockage that can be augured out.
    Do you have another cleanout further down the line? If you have an access point further down check to see if there is standing water there. Try to auger out from where you are cutting the pipe and if necessary get a camera inspection down. My guess would be just a blockage in the line downstream from where you are working and before where it joins to the mainline. If it was further down in the mainline you would get water back wherever you ran water in the house.

    One other thing that works well is an electric grinder with a cutting wheel. It can get into tight spots that a sawzall won't touch
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    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #3

    Jul 8, 2007, 02:36 PM
    Quote Originally Posted by scirocco70
    So. The questions...

    1) Why did this happen? Is older pipe prone to this? There was some concrete-like material stuck to the upper side of the pipe, which I chipped off as best I could so the fernco couplers could seal.
    Older cast iron is likely to be more brittle than newer no-hub cast iron.

    As you were tightening the chain cutter, did you rotate the cutter back and forth to score the pipe (You need to do several repetitions of a combination of lightly tightening and then rotating the cutter to make an even cut)?

    2) Would I be better off using a sawzall for the next cut(s)? What kind of blade? Fast or slow? Cutting oil?
    I don't think so, this can take quite a while and wear through several blades in the process.

    3) I now have to cut back and replace a part of the existing pipe. What is the minimum size? Is it bad to have two ferncos right next to each other, with the small patch piece in between?
    When you say "fernco's" exactly which Fernco product are you using?

    If you're joining cast iron to cast iron, you should be using No-Hub Bands.

    4) And finally... how bad is this standing water issue? This stack currently services a guest bath, which we've used plenty, and never have we had a problem with it... This part of the line IS pretty far from the septic tank, probably 50 or 60 feet, and around a corner.
    Personally, I'd run a Drain-King down it to see if you can dislodge a potential blockage.

    Also, there was a time when an 1/8" of fall per foot on 4" was allowed, that was later changed and only allowed if you increased the required pipe size by one pipe size.
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    scirocco70's Avatar
    scirocco70 Posts: 127, Reputation: 9
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    #4

    Jul 8, 2007, 04:17 PM
    Thanks Guys!

    Here's what I did...

    First I fretted a lot. Then I fixed it. I hope I did it correctly. First was to cut and clean up the mess I'd made by cracking the pipe, and get the water out of there.

    I went and got one of those drill-powered pumps, but it didn't work worth a darn. Banking on not TOO much water coming out, I just cut the pipe. I used a diamond-blade in a cheap angle-grinder. The blade was only $15, and I bought the grinder some time ago at Harbor Freight for $20 or so.. already not a lot more bucks than the $27/day to rent the snap cutter.

    Here's the great thread that I found that discusses cutting CI pipe with other than snap cutters.

    Cutting cast iron pipe - RIDGID Plumbing Forum, Woodworking Forum, Power Tool Forum

    Growler, to answer your question.. no, I did not rotate to score the pipe. I didn't know this was necessary, in the video I found on YouTube, there was no such rotating:
    YouTube - Removing Cast Iron Pipe

    The snap cutter I have is a LOT larger than the one in the video. Home Depot rents the smaller ones, but they're twice as expensive as the "real" rental place where I got the big one.

    Anyhow, I cut the pipe with the grinder, and it was really fast, easy and accurate. Wish I'd started with it.


    Growler, about the blockage, and the drain king... do you push that thing down the pipe? Or does it expand to fill the pipe space and push the blockage out by pressure? This drain has never given me trouble, and I was totally surprised to find the water in it. It's certainly not totally plugged. I could rent a Rigid K-60 and snake it, or have a plumber do it (I have a plumber coming tomorrow, for some other work. I usually get MUCH better advice on this board though). You can see in the pic below that there appears to be some sludge built up in the pipe.

    Anyhow, I realized that I had a piece of 4" CI that i could use as a replacement... part of the section i was cutting out. So, i measured three times, cut once and made the swap. I had to go to Lowes to get another no-hub band. They don't have Fernco products, but they had a "regular" and "heavy duty" version of the American Standard no-hub coupling. Naturally, i got the heavy-duty version, and it seemed to be stouter than the Fernco ones i got at the plumbing supply place when i bought the fittings.

    I used one of those T-handle "torque wrenches" to tighten, but one of the clamps on the "heavy duty" coupling stripped before the torque wrench slipped. The Fernco ones all were able to make the wrench slip. The wrench was brand-new, so maybe that was it? Anyhow, I think I'll have to replace that no-hub. Bummer. But if I have to open it up to use a Drain King anyhow...

    Also, I have some elastomeric roof/foundation sealer that I got for when it's time to seal where the new concrete is on the foundation, and I used this on the inside ring of each of the no-hub bands. Reason being, the old pipe is pretty gnarly, nowhere near a smooth sealing surface. I cleaned it up as much as I could with the grinder (regular stone), but felt that the goop might help anyhow. Just a little messy, small price to pay.

    SO! Thanks for reading this far, and thanks for all the help. I hope this thread and my experience helps the next home-owner guy who jumps in over his head with cast iron!
    ;-)
    ~aaron
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    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #5

    Jul 8, 2007, 06:05 PM
    Quote Originally Posted by scirocco70
    Growler, to answer your question.. no, I did not rotate to score the pipe. I didn't know this was necessary, in the video I found on YouTube, there was no such rotating:
    YouTube - Removing Cast Iron Pipe
    Right, they're making cuts in a vertical stack that has never been exposed to the elements or had standing water in it.

    Cutting into a horizontal line that has been buried for several decades is an altogether different animal.

    The snap cutter I have is a LOT larger than the one in the video. Home Depot rents the smaller ones, but they're twice as expensive as the "real" rental place where I got the big one.
    Yes, you rented a Ridgid Soil Cutter, whereas the guys in the video used a Rex Wheeler Cutter -- Again, this is a totally different animal.

    The Ridgid cutter is great for cast iron piping of Pre-WWII vintage, where the wall thickness can be anywhere from 5/16" to 3/8" thick.

    Cast iron manufactured during and after the war had a wall thickness of anywhere from 3/16" to 1/4".

    If you look at the cutting wheels of the two cutters, you'll notice a significant difference in the size and shape.

    Also, tools rented from the "real" rental companies show a lot more wear and tear than those rented by Home Depot (I've compared the cutting wheels on both over the years, and the "real" rental companies are less likely to maintain their equipment in the interest of turnaround).

    Anyhow, those are some nice cuts you made with the angle grinder -- I only hope you observed the proper safety precautions when you chucked that blade up into the grinder; Safety goggles, handle on the right side of the grinder (assuming you're right-handed) and that you didn't remove the guard.

    I cut my right arm half off in '99 using that same blade in a Hitachi grinder -- I would have had much better control of the tool if I'd had the handle on and would likely have missed the bone and tendons if I'd had the guard on.

    >shudders<

    Live and learn, I guess.

    As for the Drain-King -- Shove it about two or three feet inside the pipe and let it rip.
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    scirocco70's Avatar
    scirocco70 Posts: 127, Reputation: 9
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    #6

    Jul 8, 2007, 06:52 PM
    Quote Originally Posted by iamgrowler
    Cutting into a vertical line that has been buried for several decades is an altogether different animal.
    Clearly! Hopefully the next rube who reads this will skip the learning "opportunity" I've had!

    Also, tools rented from the "real" rental companies show a lot more wear and tear than those rented by Home Depot (I've compared the cutting wheels on both over the years, and the "real" rental companies are less likely to maintain their equipment in the interest of turnaround).
    This is an excellent point. The Home Depot stuff does show a lot less wear... Though I would have been better off just starting with the grinder.

    Anyhow, those are some nice cuts you made with the angle grinder -- I only hope you observed the proper safety precautions when you chucked that blade up into the grinder; Safety goggles, handle on the right side of the grinder (assuming you're right-handed) and that you didn't remove the guard.
    YIKES! I did indeed wear safety glasses, I'm pretty paranoid about that. Not so much the other stuff... I used the handle most of the time, but had to take it off for the underside. I did wish I had a clear full-face shield though, pinching my mouth shut as that "stuff" flew didn't really feel like enough. Several showers and a half a bottle of listerine later, I think I'll be OK.

    Anyhow, I'm really sorry to hear about your accident, that's serious bad mojo. I ripped a finger up once pretty decent, and have had serious respect for the grinder ever since. Not enough apparently, I'll be more careful in the future.

    As for the Drain-King -- Shove it about two or three feet inside the pipe and let it rip.

    Well, this is good news, since I can just shove it through the Wye I've already got on there. Even though I have to replace the band on the fernco, I'd rather not take this apart after all this drama ;-)



    Thanks again for your help!

    ~aaron
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