Thanks! I have this from when sealing liquid stuff, hadn't even thought for the gas, but have noticed my flexible line loses pressure after a night when the gas is off. So I shall give this a go!PTFE tape. I was tearing my hair out at a leak somewhere in my gas line (after already having lost most of the tank from the regulator not having been screwed on tight enough) that I couldn’t locate. By spending £1.80 on a roll of plastic from B&Q, I got the gas line holding pressure with the gas off for over a week.