Fuel Tank Shape?

[erebus]

We use Buna-N rubber under aluminum tanks.
No carbon, nitrile rubber, and it's white, not good for UV exposure, but under a tank who cares.

http://www.mcmaster.com/#86795k67

[CoreyTrx]

I used some 3/8" x 1" strips of azek running the length of the tank. When the coal tar epoxy was still wet I set them in it and now they are really stuck with no voids.

[WildBill]

Someone posted this a while back. http://www.yachtsurvey.com/fueltank.htm
I can tell you that definitely the neoprene or whatever rubber type strips used under the original fuel tanks caused corrosion. I still have mine and their is corrosion under the strips; I'll post pictures later. With out question the more air circulation the better.

My fuel tank was foamed in on the sides and placed on a solid panel. The tank was only coated (black looks like tar)on the top panel, not the bottom nor the sides were corrosion treated.The bottom of the fuel tank sat on three foam strips. The corrosion on the bottom took place between the foam strips and the tank. There was virtually no corrosion anyplace else. Only where there was foam on the sides or foam strips did the corrosion take place. As others have stated keep moisture from being trapped between your tank and materials that trap moisture and your aluminum tank will last longer. This is the original tank so after 40 years she'll get a new one.