Just installed my brewpi thermowell on to my kettle. There is a small leak coming through to the outside. I have tightened it now which has reduced the leak and it is sufficiently tight now to have pulled the ‘roundness’ of the kettle wall flat i.e. the kettle wall is slightly deformed by the fitting.
I am reluctant to tighten it any further. Should I have used PTFE on the thread?