Hi All, Hope you are staying safe and are well. Heres something I thought I would share with you. I recently got hold of a 1929 primus 210 with a No 4 silent burner. Its a lovely little stove and the burner works really well. (One question... Do I need the internal burner ring I have seen to go inside the burner cap that sits on the burner with the 2 U tubes? It does not have one but seems to work ok) I took out the NRV to change the cork pip as it was 91 years old and a bit dried up and shrunk. Replaced all the seals with a fettlebox kit, BUT... when using the lead washer, had problems with the pip in the NRV not sealing so out it came again. Still leaking! So after about 4 attempts, and finally cleaning the inside of the NRV where the pip rides up and down and stretching the spring, I got a seal! Ya!! lead washer now was non existent, mangled beyond repair, squashed to atoms, and no seal around the NRV... everytime I pressurized it, bubbles bubbles bubbles...oh no I thought I had a split pump tube... one last try... No lead washer left, no plastic washer ( I know I can make one from a milk bottle plastic top) but I have PTFE plumbers tape. Yes!!! I wrapped a good few turns on the nrv thread and screwed it in tight. pumped up, removed pump and dribbled water in the pump tube... way hay! no bubbles! I have lit and burned the little 210 for 5 times and boiled eggs in a pan 3 times now with the burn lasting 10 to 12 mins for hard boiled eggs, so far no leaks in the tube. The tank gets a bit hot but I am told this is no problem Question is... will the tape last??? What are your experiences with PTFE thread tape? What are your thoughts?