PTFE on gas regulator horsetail?

[ridgy]

Installing a better gas system and have a new marine regulator from gasproducts.co.uk which came with a hosetail. Does the thread need yellow PTFE on it? If it was a fuel connection I would do.

 

[Kwik Decision]

Looking at the picture, the gas tight seal is formed between the expanded (flared) end of the brass fitting, and a "seat" inside the regulator port. PTFE tape is not required. The only place thread sealants such as PTFE tape (or liquid equivalents) are needed are on tapered threads, where the fluid seal is made by the threads. The use of PTFE tape anywhere else is a bodge.

 

[ingenious]

This ^
PTFE tape only goes on tapered threads.
I'm surprised the threads on the regulator part have been painted which might make it tight to go on, check that the internal flare the pipe seals on is free from paint and clean.