Sealing plastic drain pipe connections

[Alexolcz]

Hopefully a basic question. I have replaced a pop-up style basin in the sink in my bathroom. This has now been fitted. However I am unsure how best to re-seal the joints on the plastic drain pipes. See attached photo. There is a particularly big gap in the joint at the top of the trap. I was thinking of sealing this with LS-X (as I have some) or another jointing compound, then sealing the threads with teflon tape. Would this be suitable, or can anyone give me some advise on the proper way to do this?

Many thanks in advance.
Alex

 

[Hugh Jaleak]

Which bit are you trying to seal? Trap should come with the the required washers, if it's still leaking you either haven't fitted it correctly or there's a washer missing. Top of trap should have a lip which locates into the bottom of the waste, a thin rubber O ring which makes the seal when the nut is tightened. Bottom end of the telescopic section, I'd expect to see a conical washer which sits in the joint between the tube and the trap, again when the nut is tightened the washer should be driven home to make the seal. Outlet should have a conicla rubber washer and a plastic washer behind that, then the nut. As the nut is tightened, the rubber washer is forced into the chamfer on the trap outlet, making the seal.

Never use jointing compounds on plastic products, it can attack them and cause premature failure! The threads are purely to allow the plastic nuts to be tightened, they dont form any kind of seal in their own right.

 

[Alexolcz]

Thanks a lot for your help. The bits I am having issues with are those circled in red in the attached image. The top one has a lip, but no washer. The bottom one has a small translucent washer (see second photo), but this looks a bit damaged. Any ideas if I can buy replacements?

 

[Alexolcz]

Or should I just replace the whole lot with something like this: https://www.screwfix.com/p/mcalpine-adjustable-inlet-bottle-trap-white-32mm/36251?

 

[Hugh Jaleak]

The McAlpine is a superior product, the cheap traps do have a habit of leaking. By the time you've chased around looking for replacement washers, (seems you're missing the O ring from the top of the trap already), then you may as well get a replacement. Fit and hopefully forget.

 

[Alexolcz]

Yep that makes sense. Thanks a a lot of your advice, really appreciate it .

 

[fixitflav]

Hopefully a basic question. I have replaced a pop-up style basin in the sink in my bathroom. This has now been fitted. However I am unsure how best to re-seal the joints on the plastic drain pipes. See attached photo. There is a particularly big gap in the joint at the top of the trap. I was thinking of sealing this with LS-X (as I have some) or another jointing compound, then sealing the threads with teflon tape. Would this be suitable, or can anyone give me some advise on the proper way to do this?

Many thanks in advance.
Alex

If you have gaps that need filling you're doing something wrong. It should all screw together using the correct bits. A smear of silicone grease on O-rings and washers is always a good idea.