Slight leaks from new radiator pipes.

[efiste2]

We are changing radiators in my sons new home and are having trouble with the fittings that screw into the radiators themselves. Because the carpets are down and the older radiators were slightly bigger than the new ones, we have used extended fittings to make up for the difference in length (see attached pic). However when we fill the system back up a couple seem to be slighlty leaking, we did apply PTFE tape to the threads and made sure they were tightly screwed into the radiator.
Im sure its not dripping from the compression fittings on the pipe/valve side fittings. The threads on these longer adapters are the same as the one supplied with the radiator and the same length. Can anyone offer any advice on the best way to install these.

 

[ianmcd]

Some radiators need an awfull lot of PTFE, if you can get Gas PTFE it is thicker and you dont need as many turns

 

[Exedon]

As above LOTS of ptfe or less gas ptfe
We gave up on ptfe when still getting odd rad tail leak at 20 turns
Now use loctite 55 never had a leak with it

 

[SithLordHood]

Agree with above 2 posts, I had similar issues, now i always go round with PTFE at least 20 turns, no leaks since.