Re: teflon tape
Teflon tape is not a thread sealer but in fact a lubricant. It was made to be used on tapered pipe threads as opposed to using a liquid or paste pipe 'dope'.
Yes, some people use it and swear it works but what it is actually doing is taking up some space and 'acting' like a gasket. The petcock, and tank are not tapered pipe threads but a 10mm machine thread. It needs a gasket to seal the petcock flange against the tank bung.
A gasket can be easily made. Use a material made to be used as a gasket. Don't rely on cardboard or paper.
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