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First off, I don't need any information on
sloshing compounds. I am looking for the proper material to use to seal
the seams of the main tanks during assembly. The Ercoupe service manual
talks about a 3M product 776 that is no longer available that is used to slosh
the seams to seal them. (note that the procedure for doing this only sloshes the
seams and not the entire tank). Some have said PRC and others
Pro-Seal. My A&P recommends PRC or Pro-seal but I would like some
other oppinions. I have one tank apart and cleaned and I am ready to
reassemble. It was a 1 hour effort to drill out the rivets (205 of
them). The inside of the tank was covered with a brown substance that
would not dislolve very well in Gasoline. It did soften some though.
I suppose it is dried gas residue as the tanks were full and allowed to
evaporate to the dry condition several times over an 8 year period. The
owner filled them once every year (reportedly to keep water out!!!) and then
allowed them to evaporate dry again. The tank also had a rivet missing on
the fuel outlet flange. It had been replaced with a pop rivet. I
initially removed about 12 inches of rivets around the fuel outlet fitting and
seperated the tank at that point and found that I could buck the rivets in the
outlet flange with only one edge open but after looking inside, I found the
varnish condition and decided to remove all of the rivets.
An interesting note about
the tank construction: The Baffle(sic) in my tank is a tube that extends
from the fuel cap to about 1/4" shy of the bottom The top of the tube
is riveted to the top with the same rivets that hold the filler cap
recepticle. After thinking that it didn't do much to stop fuel movement I
realized that it was for a different purpose. If the aircraft turns over,
the only gas that can drain out of the tank is what is in the tube, about 1-2
cups. With the tank upside down, fuel is below the bottom of the tube and
can't get into the tube and therefore out the cap.
My MGB fuel tank has the same arrangement in both the tank and
the vent line going to the emission system in the engine
compartment.
So anyway, anyone got an idea on the sealant to use on the
seams as I close the tank up?.
Richard
Blair
415C N99997 4J6, St. Marys, Ga |
