Leaky Sink

Discussion in 'Plumbers' Talk' started by dangermouse, May 2, 2007.

  1. dangermouse

    dangermouse New Member

    Running out of ideas here, so need to pick the collective brain of the forum.

    I've recently installed a new ceramic sink, mated with a new anti-vac trap through a new sink waste / plughole
    The problem that I have is that the sink is leaking, specifically water is running down the thread and out through the nut that secures the waste to the underside of the sink. There is a rubber washer there and it's running through that as well.

    I've tried a number of things including a washer on the sink side of the waste, a layer of silicone on the sink side, a complete new waste.

    I'm now out of ideas - anyone got anything else I can try?
     
  2. Captain Leaky

    Captain Leaky New Member

    Remove the entire waste, clean everything scrupulously
    ( new silicone will not seal to old silicone) Put a layer of silicone round the waste hole in the sink, pop the sink waste in.
    Now underneath the sink - IF the rubber washer is a good fit you don't need silicone, if not apply some silicone, tighten up - not overtight, fit trap and leave to set.

    Usually when sink wastes leak it is because there is lashings of silicone and washers, the silicone squeezes out between the washers and lubricates the whole lot. Less is more and cleanliness is very important.

    By the way I assume you mean a sink and not a basin with a pop up waste?
     
  3. dangermouse

    dangermouse New Member

    Thanks for the detailed reply, I'll give that a try in a few minutes when I get home.
    Yes I did mean a sink, no pop up waste involved thankfully
     
  4. plummit

    plummit New Member

    I must admit I like plumbers mait, If only to establish a seal. With plumbers mait, you can check the seal without waiting for anything to set.
    I like silicone, Probably a better finish. But I hate waiting !.
     
  5. plummit

    plummit New Member

    Is it a combined waste and over flow fitting?. If so seal top and bottom.
     
  6. Jimbo

    Jimbo Screwfix Select

    Try LS-X which is a silicone based sealant on rubber washer and also between waste and ceramic on the top. Sets within the hour.
     
  7. I often use LSX when doing wastes, but I have never waited for it to set (in fact a little water helps speed things up). Hand tighten everything (ensuring it was spotless to start with), then tweak it all a turn and a bit - remember the threads are weak so never over-tighten. Look carefully if the threads starts to look wonky or something "pops" whilst tightening - at best you'll have to start from scratch with the same things, or at worst you goosed the threads and need a new pack.
     
  8. dangermouse

    dangermouse New Member

    Yep, it's a combined waste and overflow and a little investigation yesterday lead to the conclusion that it's the bottom part (around the hole in the waste that mates to the built in sink overflow) that's leaking.

    It appears that the waste is slightly smaller than the hole in the ceramic so there's a small gap between the overflow hole in the plastic waste and the ceramic overflow - water is escaping through here and then running down the thread of the waste.

    Last night I cleaned everything, dried everything off then put a layer of silicone in the sink and bedded the top of the waste into it. squirted a load of silicone up around the thread from underneath, put the washer in place and did the nut up hand tight plus a bit.

    Am currently leaving it all to set and will test tonight - here's hoping because if this doesn't work I really am stuck.
     
  9. Jimbo

    Jimbo Screwfix Select

    normal clear silicon sealant won't do it, it will never set.
     
  10. Jimbo

    Jimbo Screwfix Select

    to add, it won't set because it sets on contact with air. When used as described it won't be in contact with air but water. Hence the need for a product that sets in contact with water.
     
  11. britishblue

    britishblue New Member

  12. dangermouse

    dangermouse New Member

    Ah well this time I've seen it, and if when I get home and test the latest silicone based install that I did a couple of days ago I still have a leak, I will be ordering one of those and sorting the issue once and for all.

    Thanks for taking the time to post again, it's much appreciated.
     
  13. britishblue

    britishblue New Member

    You are welcome dangermouse.

    BB
     
  14. Captain Leaky

    Captain Leaky New Member

    Before you do - you said it was a sink not a basin? If so above fitting is the wrong size
    ( sink 1 1/2 " , basin 1 1/4" )
     
  15. britishblue

    britishblue New Member

    Dangermouse, where is this sink/basin? Is it in the kitchen or bathroom?

    BB
     
  16. Captain Leaky

    Captain Leaky New Member

    he's got a sink in his bathroom and a basin in his kitchen ;)
     

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