Adapting solvent weld sink waste

Discussion in 'Plumbers' Talk' started by julez, Nov 18, 2023.

  1. julez

    julez New Member

    Any ideas on how to adapt this solvent weld waste pipe so that it heads back towards the wall lower to the floor before then rising up closer to the wall? The existing pipe does not seem to have sufficient pipe available for adding a bend lower down? Is there such things as internal connectors that solvent weld internally to existing pipe? Any other ideas? Thanks!
     

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  2. Schooldays

    Schooldays Guest

    You could carefully cut along the coupling and break out the fitting, then change to a knuckle 90 degree elbow, then along to the wall and 45 up if permitting, else use another 90 degree elbow.
     
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  3. RegB

    RegB Active Member

    What is the pipe in the floor made of?
     
  4. julez

    julez New Member

    Thanks @Schooldays. So cut down carefully along "A" in attached picture so I can reuse existing upright pipe out of floor with new coupling. Or cut across existing coupling around "B" and then carefully chisel\extract existing bend from coupling and reuse coupling? Does solvent weld separate OK? I was under the impression it welded the plastics together and was impossible to separate. Thanks again
     

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  5. julez

    julez New Member

    The same plastic as far as I can tell.
     
  6. Schooldays

    Schooldays Guest

    Yes, along A. B looks like a spigot 45 degree elbow.
     
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  7. terrymac

    terrymac Screwfix Select

    I would be inclined to cut across B ,and remove the remains from the fitting.
    If you cut A ,and damage the pipe you could be in a load of trouble.
     
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  8. just pumps

    just pumps Screwfix Select

    Had joy in the past dismantling joints with a powerful hair dryer.
     
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  9. julez

    julez New Member

    Thanks. How easy is it to separate pipe from the weld? Does heat help as per @just pumps?
     
  10. julez

    julez New Member

    Thanks. How easy is it to separate welded pipes? Does heat help as per @just pumps comment?
     
  11. julez

    julez New Member

    Thanks. I thought solvent welded the plastics chemically. How long does it take using the dryer? What about a heat gun?
     
  12. HarryL1234

    HarryL1234 Screwfix Select

    I can’t say, but I can say what I would do. Take some spare pipe similar to the one you’re dealing with, solvent weld a couple of sections of it, leave it to harden, then experiment with taking it apart with a heat gun. That will give you an idea of how feasible it is.
     
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  13. julez

    julez New Member

    Great idea! Will give it a go.
     
  14. just pumps

    just pumps Screwfix Select

    Yep both surfaces slightly melt and bond. Depends on the original installer and how well he did the job tbh, heat gun can be used but not close.
    As above is good advice from HarryL
     
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  15. The Happy Builder

    The Happy Builder Screwfix Select

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  16. julez

    julez New Member

  17. The Happy Builder

    The Happy Builder Screwfix Select

    Do not lose the rubber seal down the sewer!
     
  18. julez

    julez New Member

    OK. Progress made. Next job is to see if I can get the pipe run low enough to fit under the new vanity. Otherwise, I'll to try and take of the reducer to go back to the waste pipe.

    Technique I used was a combination of your advice, so thanks very much. See pictures attached,

    0) Cut across pipe near bottom to bring it back to the bottom coupler\reducer
    1) Check if waste goes into sewer pipe. It didn't look like it as pipe seemed to continue around bend underfloor back towards soil pipe on other side of the room.
    2) Use a hack saw blade to carefully cut into the existing internal fitting that is to be removed at 4 points around the fitting. Be careful not to cut right through to avoid damage to socket that will remain.
    3) Use a hole drill smaller than the outside diameter of internal fitting to remove. Drill out as much as possible. This made a big mess of swarf down the pipe so I would recommend have some kind of rag down the pipe that you can easily remove all the swarf with. Don't try and vacuum it out like I did unless you like fountains :)
    4) Heat up the hole drill bit while still attached to drill with a heat gun to about 150C. Insert into pipe to heat up the remaining fitting. Use pliers, screwdriver to carefully pull\prise away the fitting from the socket. It should be softer and solvent will separate more easily. Repeat for each quarter section, repeatedly heating the fitting as appropriate to avoid too much pressure on remaining pipework.
    5) Done
     

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