Another red cube leak

[Brantel]

Originally Posted by RV10Rob

Thanks, guys...

Regarding the fuel lube/sealant issue: aren't tapered pipe threads supposed to seal themselves?

-Rob

Yes and typically thread lubricant/pipe dope is used to protect the threads from galling before this seal can be established. It also fills the voids left behind from the fact that the machining process most likely won't result in a perfect match between the fittings.

[ronschreck]

Originally Posted by RV10Rob

Thanks, guys...

Regarding the fuel lube/sealant issue: aren't tapered pipe threads supposed to seal themselves?

-Rob

I a perfect world, yes. Read on...

"Pipe dope is a reference to thread lubricants, thread sealing compounds and anaerobic chemical sealant that is used to make a pipe thread joint leak proof and pressure tight. Although common pipe threads are tapered and therefore will achieve an interference fit during proper assembly, machining and finishing variances usually result in a fit that does not result in 100 percent contact between the mating components. The application of pipe dope prior to assembly will fill the minute voids between the threads, thus making the joint pressure tight. Pipe dope also acts as a lubricant and helps prevent seizing of the mating parts, which can later cause difficulty during disassembly."

[Brantel]

Originally Posted by rocketbob

ok I'm going to scream.

FUEL LUBE IS A LUBRICANT. IT'S NOT A SEALANT.

I can't count the number of times people have wasted their time with fuel lube on threads, but its one of those things that just wont go away.

Maybe that is because just about every add for this stuff says it is a lubricant/sealant. Also maybe it is because the MSDS also says its intended purpose is as a lubricant/sealant. It might also be because it works pretty good as NPT fitting dope at least it did on my airplane.

[N427EF]

I firmly believe the threads on some of the red fuel cubes are defective
in that they are not deep enough and therefore prevent a tight seal no matter what your preference for thread sealant may be.
I built 2 airplanes using "Tite Seal" on most pipe thread joints and never had a leak on anything except this time on the red cube.
Permatex will probably make up for that machining discrepancy, but Pro Seal
will put the issue to rest once and for all.

[Wayne Gillispie]

I am sure many were like Brantel and myself. It says lubricant/sealant right on the tube. I will never recommend it again and apologize if I did in the past.

I switched over to this...Leak Lock by Highside Chemicals. Works from -200 to +400*F and from deep vacuum to 10,000 psi. Switched after using Fuel Lube on 75% of my npt fittings. Don't feel bad guys, I had to reseal oil cooler and brake master cylinder seeps...SO FAR.

[rocketbob]

Originally Posted by Brantel

Maybe that is because just about every add for this stuff says it is a lubricant/sealant. Also maybe it is because the MSDS also says its intended purpose is as a lubricant/sealant. It might also be because it works pretty good as NPT fitting dope at least it did on my airplane.

And maybe it just doesn't work well regardless of what the literature says or one guy's experience building one airplane.

[jthocker]

Originally Posted by rocketbob

ok I'm going to scream.

FUEL LUBE IS A LUBRICANT. IT'S NOT A SEALANT.

I can't count the number of times people have wasted their time with fuel lube on threads, but its one of those things that just wont go away.

Thanks Bob,

I too have found, that every time someone has a leaking pipe thread,(BRAKE line, oil line,etc.), and ask them what they used for sealant, they usually say:
FUEL LUBE, or it's worthless alter ego EZ TURN! Might as well call it EZ LEAK!

Oh, by the way, if you did use EZ Turn on your high pressure fittings on your master cylinders, crawl under that panel and put your finger on those threads. Bet ya they come away PINK!

I use Loctite 561 for pipe threads.

[Brantel]

Originally Posted by rocketbob

And maybe it just doesn't work well regardless of what the literature says or one guy's experience building one airplane.

All I was trying to do is give you some ideas on why people continue to use this stuff where they do.

Why do all of you experts turn all of these threads into "manhood" measuring exercises?

I choose not to participate.

Going to the hangar now to throw out my fuel lube.

[rocketbob]

Originally Posted by Brantel

All I was trying to do is give you some ideas on why people continue to use this stuff where they do.

Why do all of you experts turn all of these threads into "manhood" measuring exercises?

I choose not to participate.

Going to the hangar now to throw out my fuel lube.

Maybe if you reread your post, and now this one, could see how someone like me could conclude the same thing.

[jthocker]

Originally Posted by Brantel

All I was trying to do is give you some ideas on why people continue to use this stuff where they do.

Why do all of you experts turn all of these threads into "manhood" measuring exercises?

I choose not to participate.

Going to the hangar now to throw out my fuel lube.

Hey Brian,

I'm sorry if I offended you and I'm sure Bob didn't mean to offend anybody, but the fact is, we try to prevent others from making the same mistakes we have made. Sometimes it is a little frustrating to us, when someone offers up, "I've had good success with"...... or "this is what I did", when their plane has yet to fly, or the brakes have never been used, or the engine has never been started.
I'm slightly agitated because I'm in the middle of re-doing an RV6 panel for a guy, and I looked down at the brake pedals yesterday and guess what I saw!
So, now, not only will the panel redo include a complete re-wire of the aircraft to bring it up to standards, it looks like I'll have to re-work the brake fluid fittings too!
Again Brian, your contributions to this forum have been manifold, and I've always appreciated them!