making good joints in screw-ring sink waste and trap connect

[JohnD]

I fitted a new overflow and plughole to a stainless sink yesterday. I re-used the existing trap, washing-machine connector, adjustable stem. They all had screw-ring connections, I took then all off and cleaned them well before reassembly. I did not fit new rubber washers. I lubricated all the joints and threads with washing-up liquid as my silicone grease was not handy Access is awkward as it is in a 500mm under-sink cabinet.

I put a dry rag underneath to witness any leaks, and I had a few drips after running the washing machine. How do you ensure a good seal on these screw-ring joints?

 

[seco services]

the trap inlet seal (thin ones) can be a pain they stretch or not sitting square all the way round.
the outlet seal (thick ones) are useally pretty good
if not change then.

 

[dextrous]

Have, on occasion, used several turns of ptfe to build up a replacement/reinforcement for old rubber seals. Naughty, I know, but noone has called me back due to a subsequent failure.

 

[gaspro1981]

Have, on occasion, used several turns of ptfe to build up a replacement/reinforcemanet for old rubber seals. Naughty, I know, but noone has called me back due to a subsequent failure.

bang on the money there son

 

[ChrisR]

So have I.
Don't use the thicker gas tape though. I thought it might be better, but no, it's definitely not as good for this sort of thing.

If all else fails, and sometimes it does, your finest BG trowel and a tube of LS-X can save the day

 

[JohnD]

thanks, I have retightened them all, if it still leaks, I will disassemble, clean again, add PTFE and lube with Silicone grease.

I don't think I've got any replacement rubber washers to fit.