Cast iron radiator - how to ensure the valve body is tight

[craig1234]

A very simple question to answer by someone in the know but anyway here goes!.
I have a cast iron radiator with valve bodies that screw directly into the radiator. I applied what I thought was copious amounts of PTFE tape to the valve thread (10 turns) but when the valve is screwed in and aligned as it needs to be, it is tight but not so tight that it can't relatively easily be twisted and thus I suspect it may leak - am I missing a trick here?

 

[terryplumb]

Not enough tape,and possibly not wound correctly in the same direction as the thread

 

[craig1234]

Definitely wound in the right direction but noted about not enough. Rather than PTFE, would a compound be better?

 

[terryplumb]

PTFE is usually sufficient ,and a smear of LSX for belt and braces.

 

[roguetrader]

Loctite 55 thread sealing cord would probably be better.

 

[Madrab]

7 wraps of Gas PTFE tape but it's horses for courses, ask 4 different guys and you'll probably get 4 different answers.
Cord, normal tape, gas tape, etc .... just whatever works but they all will

 

[craig1234]

Thanks all. I went with 15 wraps of PTFE with a smear of compound in the end. Won't know if it was successful for a while yet though!