Today's Message Index:
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1. 12:16 PM - Sealing Fuel Connectors and Loctite (George Nielsen)
2. 01:51 PM - Re: Sealing Fuel Connectors and Loctite (bigdog@bentwing.com)
3. 03:29 PM - Re: Sealing Fuel Connectors and Loctite (Charlie England)
Message 1
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| Subject: | Sealing Fuel Connectors and Loctite |
To my disappointment I noticed that fuel was leaking from my RV-6. On
closer look and analysis I could tell that this came from the starboard
fuel tank. That could be seen from paint being damaged. I removed the
fuel tank and noticed that the leak came from the wing root. Then I
tested and found no leak in the tank. Therefore it seems to me that the
leak originates in the fitting of the fuel pipe with the fuel tank.
What sealant can I use to ensure that no fuel leaks from the connection
between the fuel tank and the pipes? There are two pipes, one for fuel
to the cock and one for the fuel tank vent. Is there any possibility
that fuel can leak from the fuel tank vent? I contacted Loctite and was
told that none of their products was suited for sealing fuel. Is there
any suitable product or should I just screw tighter?
On another occasion when I was worried about fuel leaking from the
fittings of the fuel tank with the cock an aircraft mechanic
recommended that I use Loctite 603 and sold me some. I used it for the
fittings with the fuel cock. I did not notice any leaking (nor had I
noticed previously, as I used it for good measure). Now I wonder whether
that was a good idea. Would it be easy to unscrew the pipes from the
cock or is there a special procedure that I should follow.
Thanks for your replies.
George Nielsen
RV-6 PH-XGN
The Hague, the Netherlands
Message 2
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| Subject: | Sealing Fuel Connectors and Loctite |
The flared fittings should not have or need sealant on the flared surfaces. Check
the flare to make sure it is smooth, burnished and proper width. If tightened
too much the flare can crack and leak. Once unscrewed the crack will close
and can be very hard to detect. If the flare is not cracked but a bit rough or
uneven there are soft aluminum flared washers that can be inserted to promote
the seal.
If you're referring to pipe thread connections then I use Fuel Lube or EZ Turn
and crank down on them to seal. If they are angled fittings that need to be clocked
you may need to try different ones that will clock differently when tight.
Don't loosen to get to the proper position.
Greg Young
-----Original Message-----
From: owner-rv6-list-server@matronics.com [mailto:owner-rv6-list-server@matronics.com] On Behalf Of George Nielsen
Sent: Monday, October 12, 2015 2:15 PM
Subject: RV6-List: Sealing Fuel Connectors and Loctite
To my disappointment I noticed that fuel was leaking from my RV-6. On closer look
and analysis I could tell that this came from the starboard fuel tank. That
could be seen from paint being damaged. I removed the fuel tank and noticed that
the leak came from the wing root. Then I tested and found no leak in the tank.
Therefore it seems to me that the leak originates in the fitting of the fuel
pipe with the fuel tank.
What sealant can I use to ensure that no fuel leaks from the connection between
the fuel tank and the pipes? There are two pipes, one for fuel to the cock and
one for the fuel tank vent. Is there any possibility that fuel can leak from
the fuel tank vent? I contacted Loctite and was told that none of their products
was suited for sealing fuel. Is there any suitable product or should I just
screw tighter?
On another occasion when I was worried about fuel leaking from the fittings of
the fuel tank with the cock an aircraft mechanic recommended that I use Loctite
603 and sold me some. I used it for the fittings with the fuel cock. I did
not notice any leaking (nor had I noticed previously, as I used it for good measure).
Now I wonder whether that was a good idea. Would it be easy to unscrew
the pipes from the cock or is there a special procedure that I should follow.
Thanks for your replies.
George Nielsen
RV-6 PH-XGN
The Hague, the Netherlands
Message 3
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| Subject: | Re: Sealing Fuel Connectors and Loctite |
On 10/12/2015 2:15 PM, George Nielsen wrote:
>
> To my disappointment I noticed that fuel was leaking from my RV-6. On
> closer look and analysis I could tell that this came from the
> starboard fuel tank. That could be seen from paint being damaged. I
> removed the fuel tank and noticed that the leak came from the wing
> root. Then I tested and found no leak in the tank. Therefore it seems
> to me that the leak originates in the fitting of the fuel pipe with
> the fuel tank.
>
> What sealant can I use to ensure that no fuel leaks from the
> connection between the fuel tank and the pipes? There are two pipes,
> one for fuel to the cock and one for the fuel tank vent. Is there any
> possibility that fuel can leak from the fuel tank vent? I contacted
> Loctite and was told that none of their products was suited for
> sealing fuel. Is there any suitable product or should I just screw
> tighter?
>
> On another occasion when I was worried about fuel leaking from the
> fittings of the fuel tank with the cock an aircraft mechanic
> recommended that I use Loctite 603 and sold me some. I used it for the
> fittings with the fuel cock. I did not notice any leaking (nor had I
> noticed previously, as I used it for good measure). Now I wonder
> whether that was a good idea. Would it be easy to unscrew the pipes
> from the cock or is there a special procedure that I should follow.
>
> Thanks for your replies.
>
> George Nielsen
> RV-6 PH-XGN
> The Hague, the Netherlands
I think that is the 'green loctite' that is frequently used to seal
'weeping' rivets in fuel tanks. There's an STC'd product developed by
the Mooney crowd that is basically green loctite, IIRC.
Thread sealant should never be needed on an A/N flaired/tapered fitting;
the seal is between the tubing flair and the taper of the fitting. I'd
first check for proper alignment of the tubing flair and for proper
torque. If it still leaks, disassemble & check the flair for cracks
and/or deformities, and deformities on the taper of the fitting. If no
cracks but slight deformities, you can buy soft aluminum cone shaped
washers that are specifically designed to seal 'difficult' joints. Try here:
http://www.anplumbing.com/Extras/Washers+%7C+O-Rings-63.html
and scroll down until you see 'conical seals'.
Don't ignore the possibility that the prosealed hole where either
fitting enters the tank can develop a leak, and joints around the
aluminum angle in the nose of the root rib can also develop leaks (one
of mine is leaking now). Depending on where the leak is, it can be very
difficult to find the actual source; fuel will move all around along the
outside surface. The fix is to clean it up carefully with MEK or similar
solvent (be careful not to use too much, or you'll dissolve other, good,
joints) and re-seal with your choice of tank sealant. It's best to do it
on the inner side of the fitting (easy to do with the supply fitting,
since it's on the access cover). If you've got a leak around the nose
angle or vent fitting, you can try to reach inside the tank to repair
the leak, but it will be pretty tough to do. Working with mirrors and
reaching elbow - deep into the access hole just about guarantees
failure. Sealing from the outside can be done, usually successfully.
Charlie
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