If I tighten a male and female thread together so the bolt is under tension, presumably there comes a point where virtually all the load is on the flank on one side of the Vee with a good metal to metal contact giving good electrical contact. If now the thread is actually also a pipe fitting which needs to be both sealed and also a good electrical contact it rules out ptfe tapes etc. However if I were to use something like Loctite 542 hydraulic seal goo (which incidentally is fantastic stuff) would you expect there still to be good metal to metal contact on the side of the Vee as previously (assuming tightened so again under tension)? Or do these things creep under each other at the molecular level and sigificantly reduce the area of touching metal ? Using normal means I can detect no increase in resistance however in its final use this 3/4" BSP fitting may carry up to 1000 amps for short periods.
AWEM