Fuel Tank Corrosion

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Fuel Tank Corrosion

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Fuel Tank Corrosion

Posted by Lee Henderson on December 10, 2003 at 21:37:00:

Chet White had a note about this problem last September. I had the same problem
four years ago. That is corrosion of the aluminum tank to the point you could
poke a hole through the tank with a pencil. All I did to solve this problem is
to sand the tank removing all corrosion and then laid up two layers of
fiberglass mat around the entire tank. Now I have an aluminum tank inside a
fiberglass tank and the fiberglass on the outside protects the aluminum from the
salt environment. It works great.

Follow Ups:

Re: Fuel Tank Corrosion - 09:30:28 12/11/03 (0)

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Re: Fuel Tank Corrosion

Posted by - on December 11, 2003 at 09:30:00:
In Reply to: Fuel Tank Corrosion posted by Lee Henderson on December 10, 2003 at
21:37:00:


The cause of corrosion of aluminum tanks can often be traced to installation
issues. On my boat, the tank corroded at the mounting tabs. A thin piece of wood
had been used as a shim between each mounting tab and the fiberglass floor under
the cockpit floor. The shims remained wet with sea water at all times. The
failures and leaks were all around the mounting tabs

When mounting aluminum tanks do NOT use rubber for shims nor to act as a cushion
for the tank. Rubber contains carbon, and in wet/salt contact with aluminum will
set up galvanic corrosion. NEVER mount aluminum devices with rubber pads in a
salt environment

The white film that appears on aluminum in aluminum oxide, and is actually
protective in nature. The white "corrosion" acts as a barrier to corrosion. Like
stainless, air circulation is helpful in reducing the long term effects of
corrosion too

Replacement tanks are available from the facory at reasonable cost. Shipping
might be the more costly side of the replacement issue. Changing the tank on a
36 is easy...takes an hour at most. Just a filler hose, two feed hoses to the
engines, and a vent hose. And the sensor of course. I used thin fiberglass shims
I scrounged up and 4200 to attach the tank down with screws. Since the screws
are stainless, I used liberal ammounts of 4200 around the screws and holes to
(hopefully) insulate them from the aluminum and reduce galvaninc action.
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