Aluminum Gas Tank Leak

[famvburg]

There's an aircraft fuel tank sealant known under various names such as Chem Seal & Pro Seal. It's a 2 part rubbery putty that comes in different colors & thick & thin consistancies. It's obviously made for use with aluminum & is used on aircraft for more than just sealing fuel tanks. I call it a flexible JB Weld 'cause it's pretty versatile. There are also sloshing sealers available. Here's a link to a few.
Pilot Supplies, Avionics, and Homebuilt Aircraft Parts from Aircraft Spruce and Specialty Co.

[Roger S]

I've bought that low temp rod before at the fair.. not used it yet. The guy demo'd it by filling in a hole in a pop can, so it does work on thin stuff. Not cheap if you have to buy a bundle of it though.

A bar of soap rubbed on a gas leak will seal and last quite a while, unless it gets washed off.