The Murphy Builders Site

Finally figured out the leak on my first wing.

Soap bubbles finally showed after I had it flat on its underside and the
soap backed up around the seam between the Main spar U channel and the L
that nests into it -
[centered on the strut outer 3'of the 5 bays (50 gallon each side tank) and
3' past the outboard tank rib]
The suds showed the leak about 8" outboard of the outboard tank rib along
the bottom of the main spar. Tried the vacuum cleaner trick to suck some
paintable proseal in (let it run about 5 min). Pressurized it to 1/2 PSI
the next day and it held - Thought I had it. Ran it up to 1.5 psi the next
day and it showed an immediate leak - pile of suds another 12" out from the
first leak. Painted proseal the entire bottom edge of the main spar doubler
and ran the vacuum for 3 hours - tested it to 1.6 PSI and it held for 24
hrs. Yesterday, I skinned the rest of the wing and am just recovering from
the late night.

Maybe its obvious but getting the outboard top skin in under the overlapping
tank skin and gusset is not that easy. I cut a 1/2" groove in the edge of
a 18" 2'x4' shaped like the top of the rib and used a hammer to tap the top
skin into place - The arc helped it transmit the force - Worked great




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Britt,
Glad you got the leak figured out.

I just finished cutting out all 12 inspection panels and re-sealing all
along the front spar with the "leaky tank fix kit" that Darryl sent out
then installing the much larger covers.

From the lack of response from previous posts it seems no one else has or
is installing the fix. A heads up if someone is, 50% of the tank rivets
in my kit were faulty. The stem breaks off up inside the gun leaving
about 1/2 inch sticking out of the rivet. Not enough to pull a second
time.

I tried different jaws, hand puller, different pressure same result.

After talking with Robin and testing a few we determined they are pullin
g
all the way so strength is not a problem, just had to grind off about 250
stems with a dremel tool, PITA.

Scott

Finally figured out the leak on my first wing.

Soap bubbles finally showed after I had it flat on its underside and th

e

soap backed up around the seam between the Main spar U channel and the

L

that nests into it -
[centered on the strut outer 3'of the 5 bays (50 gallon each side tank)
and
3' past the outboard tank rib]
The suds showed the leak about 8" outboard of the outboard tank rib alo

ng

the bottom of the main spar. Tried the vacuum cleaner trick to suck so

me

paintable proseal in (let it run about 5 min). Pressurized it to 1/2 P

SI

the next day and it held - Thought I had it. Ran it up to 1.5 psi the
next
day and it showed an immediate leak - pile of suds another 12" out from
the
first leak. Painted proseal the entire bottom edge of the main spar
doubler
and ran the vacuum for 3 hours - tested it to 1.6 PSI and it held for 2

4

hrs. Yesterday, I skinned the rest of the wing and am just recovering f

rom

the late night.

Maybe its obvious but getting the outboard top skin in under the
overlapping
tank skin and gusset is not that easy. I cut a 1/2" groove in the edg

e

of
a 18" 2'x4' shaped like the top of the rib and used a hammer to tap the
top
skin into place - The arc helped it transmit the force - Worked great




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