Joining 32mm solvent weld to 4" cast iron

Discussion in 'Plumbers' Talk' started by Theo70695, Feb 16, 2018.

  1. Theo70695

    Theo70695 Member

    I am fitting a macerating toilet and need to couple into 4" cast. I will be using 32mm solvent weld because the run is fairly long.

    How should I cut into the soil stack? What type of drill? Is it sensible to use and angle grinder and cut a rough hole and then fit a collar. The local builders' merchant suggest a strap fitting but that seems to need an accurate hole.

    Any suggestions?

    TIA

    Nick
     
  2. kitfit1

    kitfit1 Well-Known Member

    First thing i'm going to ask is why 32mm ? 40mm would prefered shurely ? The run length makes no difference to pipe diameter but makes a lot of difference to the amount of "stuff" that can be moved along the pipe.
    A bi-hole cutter is what's needed.........................don't even think about an angle grinder :eek:
     
  3. just pumps

    just pumps Well-Known Member

    A new cutter of quality with some oil and don`t force the drill let it cut nice and slowly. Most macerators MI`s say 32mm but 40mm can be used (With a fall on the pipe ;)).
     
  4. Dave does Gas

    Dave does Gas Well-Known Member

    Your still going to need the strap on boss to attach the pipe to the soil stack to ensure a sealed joint from pipe to stack. Otherwise the brown stuff will leak out
     
  5. just pumps

    just pumps Well-Known Member

    [​IMG]
    A bad one hidden from view on the second floor in a shopping centre.
     
  6. just pumps

    just pumps Well-Known Member

    Opps, file too big.
    The photo is of 1 strap on boss with 2 32mm pipes stuffed in it and a tube of silicone used to seal it except it didn`t seal it.
     
  7. The Teach

    The Teach Well-Known Member

  8. just pumps

    just pumps Well-Known Member

  9. The Teach

    The Teach Well-Known Member

    Timesaver strap on boss was the only fitting recommended by my London building control bod,he would not pass anything else o_O

    Maybe he has shares in st gobains :mad:
     
  10. just pumps

    just pumps Well-Known Member

    Who knows ;)
     
  11. Theo70695

    Theo70695 Member

    Sorry that I haven't been back for a bit.

    Thanks for all the hints and anwers.

    Theo
     
  12. Theo70695

    Theo70695 Member

    Will this cutter do?

    https://www.screwfix.com/p/erbauer-bi-metal-holesaw-40mm/32991

    What I can't find is the rest of the kit to fit it into the drill. I will need an arbor (?) I suppose, but which one. This is the only hole that I will need to drill so as long as it lasts for the one that will be good enough quality.

    T
     
  13. Theo70695

    Theo70695 Member

    Next question:

    This is the strap on boss that I have from the local builders' merchants. What should I use to make the seal between the boss and the cast iron pipe?

    The cutter that I suggested won't do, having had a look at the boss. There are locating lugs that need to fit within the holes so I need one with a diameter of 55mm.

    2018-02-20 16.32.36.jpg
     
  14. Theo70695

    Theo70695 Member

    I did think that Iwould be able to cut a hole in the soil stack a bit larger than the OS dia of the pipe and set it at an angle as is the pitcher what I drawed. Would that work?
    Soil stack coupling a.jpg
     
  15. Dave does Gas

    Dave does Gas Well-Known Member


    No as anything falling from above will eventually block the entire soil pipe.
    The strap on boss you have shown is for plastic pipe not cast iron.
     
  16. Theo70695

    Theo70695 Member

    I know that it is a plastic strap on boss. Won't that go around the cast iron, then?

    T
     
  17. Theo70695

    Theo70695 Member

    Is this likely to be a problem? There is nothing but the vent above.

    T
     
  18. Dave does Gas

    Dave does Gas Well-Known Member

    No you have to seal it with solvent weld which in turn seals itself to the plastic pipe so that nothing leaks
     
  19. Dave does Gas

    Dave does Gas Well-Known Member

    How are you going to seal the hole around the pipe? Bodge it with mastic?

    The guys above have given you the link for the correct materials but you seem to have ignored them and gone ahead and got entirely the wrong bit for the job and offered a bodge.
    Most of us are more than happy to offer our advice gained from years in the trade but there comes a point when it gets ignored you tend to think whats the point.
     
    The Teach likes this.
  20. Theo70695

    Theo70695 Member

    Sorry that I have given the wrong impression. I bought the plastic strap on boss before I first posted. It was because I doubted the advice that I had been given there that I posted. I was intending to discuss what had been suggested to me in conversations outside this forum.

    T
     

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