Sealing Fuel lines

[mlwynn]

Hi all,

I about to seal up parts of my fuel system. What is the best way to do so? Should I use a product like EZ Turn, and if so, do you use it on the threads of the AN fittings or also on the insides of the flares? I am worried about fuel leaks and how difficult some of the fittings will be to get to once I rivet on the foreward fuselage skins.

Thanks

Michael Wynn
RV 8 Fuselage
San Ramon, CA

[robertahegy]

I use a teflon sealant like Locktight 567 on pipe fittings. The AN type flaire fittings and JIC type should be left dry and metal to metal. A good, well formed tube flaire needs no sealant and be careful not to overtighten. This will gall and damage the fittings and will cause leakage.

Roberta

[craigvince]

The builder's manual that came with my kit said to use EZ Turn on all AN fittings, so that's what I did.

[L.Adamson]

Originally Posted by craigvince

The builder's manual that came with my kit said to use EZ Turn on all AN fittings, so that's what I did.

If you want to use it for anti seizing properties, then that's fine. Just keep it off the 37 degree cone shaped metal surfaces that make the final seal.

In the refrigeration/AC business, I've often used refrigeration oil for small copper tubing such as you'd use for primer lines, by putting a small amount of oil around the tube where it goes into the flare fitting hole. This is to prevent the flare fitting from trying to twist and stretch the flare while its making it's tight metal to metal contact. This oil is just on top of the flare, and not in the mating surfaces.

Personally, for the larger flared AN fuel lines, I didn't use any anti-seize lubricants.

L.Adamson

[w1curtis]

For the flared fittings, nothing. For the pipe thread fittings, EZ Turn, Locktite or your favorite pipe thread sealant with teflon-NOT teflon tape.