[Flying Scotsman]

As part of installing my fuel drains (and the fairings I have for them), I want to use some sort of gasket-forming material rather than just EZ-Turn to ensure no leaks (because of the stack-up of drain, fairing and flange, I'm not entirely confident I can tighten the drain down enough to prevent a leak with just EZ-turn and the NPT threads fitting tightly enough). BUT...which Permatex? 1, 2, or 3 (aka "Aviation", per ACS' listing)?

What's the diff between these?

TIA, as always...

Steve

 

[Rupester]

#2 is non-hardening and good stuff. Been around for at least 50 years that I know of. I've used it to replace the EZ Turn fitting joints on my red cube ... whose leaks have given me fits. I also used it on all the brake fittings ... no leaks there!!
I can't speak to #1 (hardening version maybe?) or #3.

 

[BillL]

I discovered #3 in 70's and used it to rebuild 100's of VW engines. I never had it leak. #3 does not harden and I plan to use it on red cube, so I hope the pros will respond with some real data. I want to know too.

BTW - it dissolves with alcohol.

 

[rzbill]

Steve,
How long ya' been building?
Really, how long have you owned those tank drains?
Mine were 7 years old when I started phase 1 flying.
One started leaking like a sieve one day when sumping the tank. I took them both out and found both O-rings were cracked to heck. Had to replace.

 

[Flying Scotsman]

Just over 5 years building, and getting oh so close to being done now...so the wings are probably 3 or 4 years. I'll check the drains to see how the rubber gasket looks...thanks for the tip!

 

[6 Gun]

#3

Called permatex about which to use on screws for fuel gasket and was told #3 it has worked so far.

 

[RV7Ron]

I also used #3...and from reading the specs, I couldnt see a difference between #2 and #3...I just went with #3 because it says "aviation" on the bottle, which seemed good enough for me. Not flying yet so I cant report results.

 

[Neal@F14]

#3 doesn't harden at all and is a thinner, more runny consistency than #2 which is more of a "sloppy paste" consistency. #3 is what was used on the threads of the #8 screws on the fuel gauge sending unit cover plates of 4 RVs that I know about, and have no leaks there after many years later (since build date of 2003 on my RV-6, 2004 on a friend's RV-4, 2009 on a friend's RV-10, and 2010 on the RV-8).

It resists gasoline excellently. I know that 100LL will not work to wash it off your hands, but a mixture of denatured ethanol mixed with a little MEK will remove it.

 

[LettersFromFlyoverCountry]

I'm not entirely confident I can tighten the drain down enough to prevent a leak with just EZ-turn and the NPT threads fitting tightly enough).

Not what you're asking but you should be confident that, indeed, you can.

 

[zilik]

I also used #3...and from reading the specs, I couldnt see a difference between #2 and #3...I just went with #3 because it says "aviation" on the bottle, which seemed good enough for me. Not flying yet so I cant report results.

Ron,

The #3 you used will be fine for many years. I've been using the stuff since 2nd Grade.