Can the tank sealant "dry out" if not full?

[Jeev]

I have a 78J with a tank reseal a year ago.  I also keep the aircraft under a shade in Las Vegas where it is very dry and often over 100df.  I have read in other post that the sealant can "dry out" and cause leaks if the tanks are not topped of.  During the summer and high DA's i usually keep the tanks at the tabs and sometimes go a week with out flying.  So to the experts ( I've only owned since Aug) is this true?

Thanks,

Jeev

[N6843N]

I do not believe in the "dry out theory". But here is something to ponder. The area of the tank, top, which also gets the sun, I believe will expand much quicker than the lower area of the wing which gets no solar heating and also has, lets say 15 gallons of liquid to transfer any heat to. Even in the shade I think you have a differental rate of heating and cooling which may cause a seperation of the sealant.

[carusoam]

I believe the reference is to how hot the wing surface can get when left in the sun. 

When the tank is empty the sheet metal gets very hot.   When the tank is near full, the fuel acts as a heat sink, the sheet metal does not get nearly as hot.

The sealant, like paint, has it's best longevity when it is not overheated.

Saving the paint and the sealant sounds more challenging in sunny Las Vegas, than it does in the North East.

- Anthony -

[Piloto]

Quote: Jeev

I have a 78J with a tank reseal a year ago.  I also keep the aircraft under a shade in Las Vegas where it is very dry and often over 100df.  I have read in other post that the sealant can "dry out" and cause leaks if the tanks are not topped of.  During the summer and high DA's i usually keep the tanks at the tabs and sometimes go a week with out flying.  So to the experts ( I've only owned since Aug) is this true?

Thanks,

Jeev

[Jeev]

Thanks for the info guys, although my Mooney is outside it is under a shade that shields the entire aircraft from direct sunlight all day so the top of the tanks are not exposed to the heating of the sun.  So if I follow the idea correctly; as long as it is not in direct sunlight (expanding/ contracting with temp) I should be good?

[N6843N]

It would be interesting to find out what the temperature differential would be, with say half tanks, on a 110F degree day. If you or a friend have a temp gun maybe you could "shot" it and let us know. I know when I lived in KPSP there was a big difference and I was in a hanger. If you get a chance to find out post it here please. 

[Alan Fox]

I have read the biggest danger to tank sealant is hard landing gear bisquits (donuts)

[JoeSpeed]

Full Tanks are best for sealant and reduction of condensation, However Full tanks reduce useful load and compress the rubber shock disks. A full tank seal can run 10k and the shock disks are 1k + labor. Make your best choice

[fantom]

Quote: Jeev

Thanks for the info guys, although my Mooney is outside it is under a shade that shields the entire aircraft from direct sunlight all day so the top of the tanks are not exposed to the heating of the sun.  So if I follow the idea correctly; as long as it is not in direct sunlight (expanding/ contracting with temp) I should be good?

[Guest Anonymous]

Quote: fantom

 Gee, does that mean I don't need to worry abut it in Seattle?

Actually, there may be something to it.  I have not heard a lot of issues with tank leaks around here.

RFB