Speaking of threads, why do "experts" put Teflon tape on every F'n fitting that has threads ??

[Rajobigguy]

The actual torque for fittings is FAR FAR lower than almost everyone thinks.

Over-torquing causes galling and splits banjo fittings, mushrooms and cracks flare types and generally fucks things up.

Everyone over tightens fuel, oil and brake fittings.....it's an insecurity thing because they don't actually know the spec.

I like the liquid sealant myself, it cleans up better and does a better job sealing NPT.

Like anything, almost EVERYTHING has a spec, lubed, dry, type of lube etc....RTFM or keep on guessing....

Good quality AN fittings have a standoff spec. and there is a gauge that you use that fits between the stationary and threaded ferrule nut. I have a set of those gauges that are like brand new because they have never left the case.

 

[Luvnlife]

My take. The only time to use Teflon tape or paste is on tapered threads like pipe threads. You don’t need both just one or the other. The Teflon is a lubricant as you thread them together with the tapered threads creating the seal not the Teflon. I’m sure there are some paste or liquid that claim to seal but not needed but if it works it works.[emoji106]

 

[ParkerRat]

I always thought Teflon tape was used as a lubricant. Not for sealing purposes..

Exactly, I was taught by someone smarter than me that it was used to lubricate the threads not seal them

 

[Justfishing]

Not a plumber but what is the downside to having Teflon tape on those fittings?


Sent from my iPhone using Tapatalk

You have to understand what the seal is.

Pipe threads are tappered. The threads deform to each other to an extent and seal to each other but a perfect seal is not made. Tape or paste does help fill voids and also facilitates better tightening.

A brass ferrel in a compession fitting becomes the seal. Have you ever tried to get one off a copper pipe. The taper on the ferrel seals against the seat on the surface of the fitting. Tape or paste can interfere will the sealing surface.

A flare fitting seals against the corresponding sufaces. Again tape or paste can get between the sealing surfaces.

So it reallly comes down to what creates the seal. If the designed sealing surfaces are doing their job than the tape or paste does nothing. On the other hand it may interfere and cause a let.

 

[riverroyal]

There is also teflon tape for stainless threads. It does work better.
If it didnt, by now i would have known by all the steam hitting people on the tram route at universal

 

[riverroyal]

Fun fact....take a dry steam ran through stainless for no contaminants and mix it with liquid nitrogen at pressure and you get a nice cool fog that looks like smoke.
If the steam pressure gets low you shoot ice chunks. This i know...

 

[BaileyP]

The Blue Monster Teflon tape is the best once you use that the rest is all junk imo

 

[REVENGE 97]

Only use teflon tape on "tapered pipe" fittings, never on ferrule, AN or JIC types.

I see it all the time on flare fittings for fuel systems and that's a big NO, NO!!!!!

 

[traquer]

Never used tape on the drain plug, doesn't leak

 

[rrrr]

Never used tape on the drain plug, doesn't leak

View attachment 858771

If your drain plug is 3' under water when the boat is at rest, it is holding back 1.302 PSI from sinking your boat. Kinda makes it obvious why it doesn't leak, huh?

 

[waterhorse]

If your drain plug is 3' under water when the boat is at rest, it is holding back 1.302 PSI from sinking your boat. Kinda makes it obvious why it doesn't leak, huh?

Head pressure at sea level is only .43 lbs per vertical foot, so 3 feet underwater would only be 1.3 PSI. Whoops, I just realised you put the decimal in the wrong position. Disregard, sorry.

 

[rrrr]

Whoops, I just realised you put the decimal in the wrong position. Disregard, sorry.

Wrong position? Huh?

 

[wettrthebettr]

I have always used Blue Magic Pipe Thread Compound, it has an anti-galling compound, that seals all types of metal and plastic threaded connections.

 

[waterhorse]

Wrong position? Huh?

My mistake, for some reason I was reading that as one thousand three hundred two.