The Murphy Builders Site

Thanks for the replies lads. Another question, please. Does anyone have an

a wet wing is superior or inferior to a welded aluminum wing tank? I just

say that a wet wing would ultimately hold more fuel than a welded tank fit

space and that sure makes good sense. What I'm getting at is, if space was

a consideration and a person had the skills to weld a tank together, what

best route to follow? Thanks.

Dave Stroud, Ottawa, Canada
Christavia C-FDWS
Fairchild 51 early construction

----- Original Message -----
From: "Ralph Baker" <rebaker@ftc-i.net>
To: <murphy-rebel@dcsol.com>
Sent: Thursday, February 26, 2004 6:04 PM
Subject: wet wings

The Pro Sealing is one of those things best looked back on and not
forward to. However, it is not as bad as you expect. Be sure the
surfaces are scrupulosly clean and Scotchbrited. Be sure gap filler
plates at the stringers and any other penetration fit as closely as
reasonably possible. Mix accurately. Mix only as much as can be used
before setup. Setup occurs much faster as temperature rises above 70
degrees F. Wear old clothes. Wear latex gloves. Use 1/2" stiff
brushes to spread material as well as small spoons. Have a helper who
knows how to help. Remember, no tank ever leaked from too much Pro
Seal. Think the sequence of work through before opening the Pro Seal
container. Get a can of acetone for Pro Sealed clecoes. Use still
wires to maintain rib and filler plate alignment as parts are brought
together. Use a coat of "brush grade" Pro Seal in the "tub" after
initial assembly. Be sure that Pro Seal does not form a dam between the
root rib and stringer preventing complete water sumping.

The brush grade Pro Seal is a lighter viscosity that can be brushed
rather than the "peanut butter" consistency. Some have advocated
thinning the thicker material with MEK but I chose to order rather than
chance changing the chemistry. Do not put more than 2-3 pounds of
pressure at a max for leak tests. 1 1/2 pounds will show leaks. I
found that a stethoscope with a tube would hiss at any leak and the 2
that we had were where they could be found this way. I do recommend
that prevention is the best course.

The penetrations, such as at the stringers, are closed with .020
aluminum made to suit and riveted in placed with Pro Seal. A search of
the archives will turn up more commentary than one would imagine as
well.
Ralph Baker

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The Pro Sealing is one of those things best looked back on and not
forward to. However, it is not as bad as you expect. Be sure the
surfaces are scrupulosly clean and Scotchbrited. Be sure gap filler
plates at the stringers and any other penetration fit as closely as
reasonably possible. Mix accurately. Mix only as much as can be used
before setup. Setup occurs much faster as temperature rises above 70
degrees F. Wear old clothes. Wear latex gloves. Use 1/2" stiff
brushes to spread material as well as small spoons. Have a helper who
knows how to help. Remember, no tank ever leaked from too much Pro
Seal. Think the sequence of work through before opening the Pro Seal
container. Get a can of acetone for Pro Sealed clecoes. Use still
wires to maintain rib and filler plate alignment as parts are brought
together. Use a coat of "brush grade" Pro Seal in the "tub" after
initial assembly. Be sure that Pro Seal does not form a dam between the
root rib and stringer preventing complete water sumping.

The brush grade Pro Seal is a lighter viscosity that can be brushed
rather than the "peanut butter" consistency. Some have advocated
thinning the thicker material with MEK but I chose to order rather than
chance changing the chemistry. Do not put more than 2-3 pounds of
pressure at a max for leak tests. 1 1/2 pounds will show leaks. I
found that a stethoscope with a tube would hiss at any leak and the 2
that we had were where they could be found this way. I do recommend
that prevention is the best course.

The penetrations, such as at the stringers, are closed with .020
aluminum made to suit and riveted in placed with Pro Seal. A search of
the archives will turn up more commentary than one would imagine as
well.
Ralph Baker


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Archives located at https://www.dcsol.com/default.htm
Archives public username "rebel" password "builder"
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Be sure gap filler plates at the stringers and any other penetration fit as closely as
reasonably possible.