Jig for squeezing PVC into donut gasket for Cast Iron soil pipe

Discussion in 'Toilet Forum discussions' started by rosenn, Jun 12, 2010.

  1. rosenn

    rosenn New Member

    Messages:
    16
    Hello all,

    I mentioned in my last thread that I simply could not push a close nipple of 4" PVC into a donut compression gasket to connect to an 4" XH Cast Iron hub. After trying all tricks I could come up with, I ended up building a quick jig with some scrap 2x4 ends and 3/8" readibolt. In the pieces that clamp around the hub I put curved notches into them freehand on a power miter. It doesn't need to be pretty, just needs to work.

    I clamped the thing around the CI hub, and cranked down on the nipple. In a few minutes of alternately tightening each nut, the nipple was pushed in completely. If you tackle one of these jobs as a DIYer, this may save you a struggle. Anyone have a better idea, I can bank it for the next time I need to replace a lead closet elbow with PVC.

    -Nelson
    SoilPipeJig.jpg
  2. shacko

    shacko Master Plumber-Gas Fitter

    Messages:
    561
    Location:
    Rosedale, Md
    There's a chance you had the wrong gasket, the gasket has to be bought by xh x sch. 40 pvc, you may have had a standard gasket, which you may get together with a lot of cussing and strain. You did put lube on the pipe, didn't you? Did you knock off the sharp edge on the pvc?, makes it a lot easier.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,149
    Location:
    New England
    Fernco makes the donuts in 1/16" increments around the standard diameters to account for a 'proper' fit. CI hubs are not set in concrete as to their actual size - it varies by manufacturer, foundry, and when it is produced, along with standard and heavy duty. While local supply shops may only carry two versions that covers the common stuff sold locally, depending on the age, those two sizes may not provide the proper fit and you (should) special order one. If you have the 'right' size, you should be able to insert the pipe into the fitting without that jig. If it is tight, it could save waiting for an order to arrive with the right one. What you don't want, is it too loose, so it doesn't make a good seal.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,837
    Location:
    Cave Creek, Arizona
    I replace lead closet bends with a cast iron one using a lead/oakum joint which takes a lot less time than your method and is much more stable/secure also.
  5. rosenn

    rosenn New Member

    Messages:
    16
    All excellent suggestions

    Hello all,

    Yes, lead/oakum would have been quicker for the experienced plumber, but I am not experienced in that. I do not have a joint runner, yarning chisel, and inside/outside caulking chisels. I would like to work on that some day, as they are beautiful joints when finished.

    I could have used a Manhoff fitting, and made the joint with oakum and plastic lead. Again, no experience with that, so I went with what seemed simpler, but ended up only being simpler in a roundabout way.

    I did put a gentle taper on the very end of the PVC so that it would slide in easier. I lubed the outer surface of the PVC and inner surface of the Fernco donut, dish soap on both. Yes, it's an off-the-shelf donut for 4" XH CI from my local wholesaler, but the fit is nice and tight, perhaps I could have special ordered one just a 1/16" looser, and it would have gone in by hand.

    What I did not try, but have thought about since I did this, was that I could have kept the PVC piece long, which would have given me more to push in, and once in I could have cut it to length. Not sure if it would have made a difference.

    All that said, the jig is built and worked like a charm.

    Thanks for all of your help.

    -N
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,135
    Location:
    Bothell, Washington
    The rubber seal and pipe take me very little time to pop in.
    I can't imagine why hj would think it would be so hard.

    I use a 2x4 on the end of the pipe and a hammer. A couple of taps with the hammer and it's seated.

    [​IMG]
    I normally just pull the lead out of the cast iron tee, and use a 4x3 flush bush into a insert rubber pipe donut.

    [​IMG]
    Last edited: Jun 14, 2010
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,837
    Location:
    Cave Creek, Arizona
    The old lead oakum hubs were not always concentric, the way the Ty-Seal and modern ones are. Sometimes there are "offsets" where the two sides of the mold did not meet perfectly. In addition, the hubs are often corroded. For these reasons, I prefer not to rely on a gasketed connection into an older hub. Just a preference. In addition, I would use a cast iron closet bend and that would not be a good candidate for a sledge hammer, and the "jack" method would also be difficult to fit to the curve of the bend.
  8. rosenn

    rosenn New Member

    Messages:
    16
    Anyone have experience with the Manhoff fitting?

    I haven't found much mention of them in this forum, but in other on-line forums have come across mention of a Manhoff fitting - a piece of Sched 40 PVC desigend to fit into CI hub, and to be joined with oakum and plastic lead. There was some mention of people using regular lead, but that doesn't make much sense. Lead melts at over 600 degrees, and Schedule 40 PVC is not rated beyond 160. I wouldn't trust a joint like that in the long term.

    As best I can tell there are a finite way to join to an old CI hub:

    1. New CI spigot
    2. Cut the brass nipple of the closet bend and use a mission no hub coupler
    3. Donut gasket and pvc nipple
    4. Manhoff fitting and oakum/plastic lead

    If the donut didn't fit well, the #4 option may be good. Anyone ever do that?

    -Nelson
  9. shacko

    shacko Master Plumber-Gas Fitter

    Messages:
    561
    Location:
    Rosedale, Md
    rosenn:>>>Lead melts at over 600 degrees, and Schedule 40 PVC is not rated beyond 160. I wouldn't trust a joint like that in the long term.<<<

    I think you are using the temperature rating for PVC under pressure.

    Before the advent of the gaskets and donuts it was common practice to pour a lead joint with a PVC adaptor, there has to be millions of them out there :)
  10. EC65

    EC65 New Member

    Messages:
    1
    Location:
    san antonio
    man, I don't know how to thank you. I went to lowes and home depot and know one knew how the heck to join pvc to cast iron. thanks to this illustration I was able to duplicate this jig and complete the task.

    moreover, I tried hammering it in, but no success.

    this tool is A-W-E-S-O-M-E!
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,149
    Location:
    New England
    FWIW, the hub of CI can vary considerably from one foundry to another, and over time as processes and techniques get updated. As a result, you may need to be more careful on the selection of the donut. If you have the right sized one, it's not that tough to get it inserted. If it's too loose, it'll leak. If it's too tight, you may need something like that jig to jam it in there.
  12. wjcandee

    wjcandee Wise One

    Messages:
    1,898
    Location:
    New York, NY
    I am constantly amazed at how much fantastic information exists on this site. Thanks for sharing your success!!

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