I picked up a sumped, steel factory F body tank and had to weld up a couple spots that leaked. I let it sit like 48 hours with water in it to re check for leaks and it has some surface rust on it already! Do you guys seal the insides of the tanks with anything? The welding burned off the galvanize or whatever it is that protects the metal and it rusts very quickly now apparently. I will be running E85 if that matters.

 

I think Eastwood offers some type of gas tank sealant.

 

Try this stuff. I used it on the top of my sender in my 3rd gen and use it on my dirt bike gas tank with no issues

 

Its not leaking anymore. I just want to prevent it from rusting. I think E85 is fairly corrosive and I dont want issues with it contaminating the fuel system. I figured this would be pretty common for the sumped oem tanks when welding them. I can't find any info on if this is an issue or what to do.