Technical Fuel fitting tape

What is the BEST tape for fuel fittings?

 

None

 

AN fittings, inverted flare, 45 degree brass….shouldn’t need any.

 

Depends on the fitting....you didn't tell us what it is....but not many of them need tape. Flares and banjos don't, only tapered pipe threads do.

 

IF...........you use something that you might want "tape" on, I'd use a paste rather than tape. My experience with tape is it usually doesn't stay on the thread when tightening.....gets pushed back. Paste or a gel get pushed around some too, but they stay wherever there is a low spot or gap. For a fuel system, you are better off with fittings that do not use any tape or paste but have a solid metal connection that seals on its own. Might look at the industrial JIC fittings as they come in steel and are usually cheaper than AN fittings. They work on industrial equipment like bulldozers, so they are fine for car needs.

 

Some fuel components and brake components have NPT thread and they need sealant.

 

I should have been more specific sorry. I have an old system I am putting back together that is 3/8 NPT.
Thank you for all the input.

 

If you're dealing with pipe thread, PROPERLY used teflon tape is good. Clean the fitting well. Start one thread back from the end of the fitting....don't start it all the way at the end of the threads because that is the part that can tear off and leave slivers of tape inside the line/fitting that can cause trouble. I usually use 2 to 3 wraps. Looking at the end of the male fitting that will thread into the female part, wrap the tape clockwise tightly so the tail end of the tape, when you tear it off after wrapping, is not being peeled back as it engages the female threads. Properly applied tape will thread into the female part along with the male threaded part and work it's magic.

I have probably used a couple miles of teflon tape with success in my previous job of installing high-purity water systems.

Lynn

 

Pipe tape is for houses, use a fuel resistant thread sealant like Permatex.

 

Do not use Teflon tape, one small piece of Teflon in a carb jet will drive you nuts. I use Loctite 569 thread sealant on automotive pipe threads.

 

It must be extremely difficult to leave the first 2 threads showing beyond the tape. Paste is better but even more care is needed to keep it off the end. Permatex or locktite is what you want if you want good stuff.

 

I would use the Locktite 569 as woodiewagon46 suggested and use it sparingly. As others said, teflon tape and fuel systems have a bad history when mixed and many of us have fought that bit of teflon tape in a carb passage in the past.

 

Tape is fine if installed correctly like Lake Harley stated. It is not a sealant anyhow , it is a lubricant.

 

I’ve never heard of using any sealant on pipe threads (NPT ) .
Isn’t the whole idea of using taper threads to create a seal ?

Tommy

 

Tapered pipe threads always need a sealant, the inventor designed it that way.

https://support.jamestowndistributo...to-properly-seal-fuel-fittings-and-fuel-Lines

 

The tape most certainly is a sealant with lubricant properties. It’s made to squish out of tight metal to metal areas and into the low voids. NPT threads are cut with a void ( on purpose) so the tape moves into the void and seals.

 

Permatex #2. Leave overnight if possible. Has never failed me since my father showed me at 14… I’m now 78.

 

ZERO, NONE, NADA, DON'T.
Most plumbers...don't even use..."plumbers tape" ! I received this comment from a...licensed plumber.

Accurate enough answer ?
Question...what type of fittings are you using ?

Mike

 

If you're under the impression that permatex, dried , cured ,fried , fossilized , whatever will keep a FUEL fitting from leaking , you're sadly mistaken ! Sealers / dopes of any sort have no business around brake systems either .

 

I just use ordinary teflon pipe sealer tape.
I put it in a jar of petrol overnight to see if it would melt/ dissolve and it didn’t so just went ahead and used it.
I keep it off the end thread so it doesn’t get torn into the fuel passage as I fit it.
Still in working order many years later when pulled to pieces.

For @Mike VV comments above,
30 plus years of fixing water pipes with the same stuff……..80psi ….
and sometimes fixing plumbers and water experts leaking pipes.

 

5-7 psi, so not much pressure. A couple wraps of Teflon tape should be enough to seal 95% of pipe fuel fittings.

 

That's the point that most people miss.... It's a lubricant to help you get the fitting tighter so the threads can seal (per the design intent). Overtightening can be a hazard though...
For those that do not understand "pipe threads", take the time to research a little bit.... There are two types of pipe threads: NPT and NPTF. NPT is what you find in water systems... NPTF is designed to be used in higher pressure, hydraulic or pneumatic systems. While the thread pitch and taper are the same for both, the male and female thread profiles differ, as do the sealing surfaces. Take the time to understand the sealing method of the two.

EDIT: NPTF indicates a class of pipe thread denoted as "Dryseal" Hope my omission wasn't confusing or vague.

 

I have 35 plus years , sealing threads in the pipeline field of work . As Mr.Squirrel , defined only NPT threads need a sealer . There is a huge difference brand of Teflon Tape also . Most products were sold as a lube to allow deeper thread engagement to seal . In today’s world of off shore hardware , tape is used to seal dissimilar thread pitch . I only use John Crane products . For most NPT threads on my car or bikes , Loctite is my go to product .

 

I wish the person who did the double flare fuel and brake lines on my '53 had read this before they started! Every flare fitting had goopy teflon tape on it (the flare is the seal, the thread only engages the 2 surfaces together). BSP/NPT - use teflon tape or thread goop, flare fittings- NO!. I get the rolls of the ultra-thin imported rolls of teflon tape (usually from far Northern North Australia) and save a lot of time by throwing them straight into the rubbish bin.

 

All we ever used in R&D at GM was Loctite 545 thread sealer.

 

Some very common things found on cars with NPT in both fuel and brake systems. Needing thread sealants.
One unit has both types NPT and NPTF.

 

No I’m not. Permatex #2 never actually dries but will get hard All I’m saying it’s what I use on a liquid pipe thread fitting on an engine: water, gasoline, or oil with the exception of aluminum. I wipe it clean when I’m done and it will unscrew when needed.
Technically no product is needed on a pipe fitting but people using incorrect products are doing more harm than good.
It’s important in my opinion to use a product on an aluminum pipe fitting to prevent galling or corrosion. On AN straight threads I also lube the o-ring and a small amount of “Silver-Goop” on the threads.

 

This is the right answer

 

How wrong you are. See these fittings? They are from Wilwood, notice the factory applied sealant?

 

Whenever possible I buy fittings with factory applied sealant.

They are often just cents more, and cut down on time and materials at my end.

On NPT fittings, where interference fit of the threads makes the seal, manufacturing tolerances can stack, and lead to a leaking combination without sealer.

As has been mentioned, the sealer acts as a lubricant, allowing the threads to engage farther.

It should be noted that the sealer line begins after the third thread. This has been an enforced rule wherever I have been in a leadership role.