Stop in for a cup of coffee

Eastwood products actually sells a gas tank epoxy based sealant for this type of repair. But it’s not much cheaper than just replacing the tank. If it were me, I’d buy new tank, powder coat it then epoxy it from the inside and it should never rust
That was the plan for the tank I have, buddy was going to powdercoat it for free but he never got around to it and boy am I glad he didn't.