So once you get it tight, a lot of people will take a sharpie and you'll just mark somewhere.

Let's say if you have it hooked right here and you can see this flat right here, you'll put a sharpie mark on the flat and then just put a wrench and turn that about half a flat down.

And that's all it realistically should take. With it being such a small sealing surface on the inside, if you do put a big pipe wrench on it, or something really long (breaker bar or anything), it can cause it to micro fracture on the inside.

And it'll cause just like a little small crack. You won't even be able to see it. You may be able to feel it with like the tip of your finger nail or something, but the crack can be really small and it'll cause a leak.

95% of the time, if you put it on hand tight then corner turn and it leaks out of the back of the nut a little bit, tighten it up just a little bit more.

But if you have to put a big wrench on it and it's still pouring out the back, something inside there is cracked or something on the male side is not letting it seal.

For example, say you drop a fitting, pick it up, wipe it off, and put it back in. That fitting can cause a little bit of damage to that cone on the inside of the JIC, and any damage on that perfectly circular cone will cause it to leak almost every time.

A lot of people try to take an old rusty fitting and buff it on a buffer wheel. I've seen just the buffer wheel make it just a little bit out of round. That little bit will cause it not to seal.

You can tighten that old one seven times and it won't work. But, you put a new one in there and it works the first time.

JIC is a very good seal. But it's a metal to metal seal and the actual cone is not super thick. So, if you tighten it down way too tight, it will cause it to break and then leak behind the actual nut.

That's realistically all there is to a JIC fitting. You can put a little bit of hydraulic oil or anything on the actual male surface.

It kind of reduces the amount of friction when you're actually tightening it up and that'll make it a little bit easier to install it.

And then as I said, a lot of people will just go by the flats.

That's what they call this right there, the flat. So you'll put it on there, get it snug and tight, and then you only want to do half a flat.

So when you tighten it down, it'll work like that.

Maybe one flat, but after that one, once it's hand tight, it should only be half a flat.

Anything past that, you're going to break it.