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    Hooah's Avatar
    Hooah Posts: 1, Reputation: 1
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    #1

    Aug 15, 2007, 10:46 PM
    Trouble replacing a cast iron 90 with PVC - lumps to the head
    I'm helping a friend replace a section of 4 inch cast iron sewer line that runs across the ceiling in his basement. This cast iron line turns a horizontal corner (90 degrees with a clean out) along the ceiling right at the bottom of his basement stairwell. It's above the last few stairs and anyone over 5'8" hits their head (at least once) on that corner of the pipe as they descend. Using a snapper we've removed the cast iron 90 and snapped the straight pipe a foot or two back on each side. Using no hub bands, we've attached 4 inch street PVC 45's to each side and attempted to connect them with a straight shot of 4 inch schedule 40 PVC pipe (thus rounding out the turn and eliminating the lump producing 90). We're not worried about losing the clean out.

    The problem is that we can't get things to line up. No amount of tweaking (moving the 45's along the side lengths, light pushing on the pipes, angled wiggling in the no hubs) gets us to a point where the 45's line up and connect properly with a straight shot of PVC. My best guess is that the two sections of straight cast iron pipe leading into this corner didn't meet at or near a true 90 degrees and that the variation in angle must have been compensated for by slop in the older lead and oakum joints. We just can't get the same flexibility in the no hub bands and PVC adhered joints. We're going to try a 45 on one end and a 22.5 on the other tomorrow but I don't have high hopes. Am I way off base here? Are there any tricks for dealing with non standard angles when converting CI to PVC? We patched it together with a loose fernco for the night but don't see this as a long term fix. Any help appreciated.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #2

    Aug 16, 2007, 03:05 AM
    Quote Originally Posted by Hooah
    I'm helping a friend replace a section of 4 inch cast iron sewer line that runs across the ceiling in his basement. This cast iron line turns a horizontal corner (90 degrees with a clean out) along the ceiling right at the bottom of his basement stairwell. It's above the last few stairs and anyone over 5'8" hits their head (at least once) on that corner of the pipe as they descend. Using a snapper we've removed the cast iron 90 and snapped the straight pipe a foot or two back on each side. Using no hub bands, we've attached 4 inch street PVC 45's to each side and attempted to connect them with a straight shot of 4 inch schedule 40 PVC pipe (thus rounding out the turn and eliminating the lump producing 90). We're not worried about losing the clean out.

    The problem is that we can't get things to line up. No amount of tweaking (moving the 45's along the side lengths, light pushing on the pipes, angled wiggling in the no hubs) gets us to a point where the 45's line up and connect properly with a straight shot of PVC. My best guess is that the two sections of straight cast iron pipe leading into this corner didn't meet at or near a true 90 degrees and that the variation in angle must have been compensated for by slop in the older lead and oakum joints. We just can't get the same flexibility in the no hub bands and PVC adhered joints. We're going to try a 45 on one end and a 22.5 on the other tomorrow but I don't have high hopes. Am I way off base here? Are there any tricks for dealing with non standard angles when converting CI to PVC? We patched it together with a loose fernco for the night but don't see this as a long term fix. Any help appreciated.
    You need a flex coupling.

    4 inch Flexible Coupling P105644 by Fernco | DoItYourself.com

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