Best way to seal threads?

I just put a pressure gauge inline on my incoming water pipe. I used a T-piece with flare fittings on each end.

I have found that flare fittings are by far the best and most reliable fitting.

However, where I have connected male/female threads on the T-piece I am getting a very slow leak which is annoying the hell out of me. (1 drip every minute or so). I have dismanteled the thing 3 times but some of the drips persist.

I am using "Stag" thread sealant and teflon tape on the thread and tighting up the connects very tight.

My question is, what is the best thread sealant to use? I have encountered the problem often where I have had to disassemble some plumbing 2-3 times before I get it right.

How about Loctite 567? Anyone use it?

Thanks.


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