Hmm, I put ptfe tape on my argon/CO2 regulator, should I not have done that then?PTFE is a no-no for the connection between cylinder and regulator, since this is designed to be used without any sealing materials i.e. direct metal to metal contact.
Pure PTFE can be expected to be compatible with O2, but suppose somebody is making PTFE which is a mixture of PTFE with something else, or maybe coated with something else? Hands up, who remembers the three Apollo astronauts burned to death in seconds in a pure oxygen atmosphere, when everything around them was supposed to be fireproof?not a problem using proper ptfe tape on oxygen fittings i have it on my pressure gauges. if the bullnose doesnt seal properly on the bottles rub them over with a bit of fine wet and dry fit on the bottle loosely tightened and revolve the regulator back and forth . then tighten. any irregularity will disapear and will seal properly