Corrosion on bottom of fuel tank

[Max_Florida]

I pulled the fuel tank today and was cleaning off the bottom of it. There were three strips of some type of rubber that had either adhered on their own or were glued to the bottom of the tank. When I started pulling them off I noticed that there was corrosion under them in some places. One spot in particular was bad, so I kind of dug at it with a screwdriver since it was pretty soft. Sure enough I ended up with a little hole.

$405 for a brand new custom tank. I'm already way overbudget for the current round of projects, so I'm looking to get this fixed somewhat cheaply.

I called around and found a guy who will weld on a patch.

What I was thinking of doing was cutting off the bottom of the tank(leaving a 2" lip for him to weld to), cleaning the tank out and then having him weld on a new bottom.

Is there any reason not to go this route? Is the aluminum inherently corrosion resistant or does it need to be treated/coated? Is there a particular type of aluminum I need to use or will any "good" 1/8" aluminum do?