I would use two channel locks that are 12-14 in long. Channel Lock number 420, I think and tighten until it is difficult to make it screw in. I would pre solder the adaptor before applying any pipe tape as the tape has a tendency to vaporize leaving you with leaks. I only use teflon pipedope which can be soldered and still have no leaks. There is a time and place for teflon tape but I use it very rarely.