It was not a big surprise that the fuel tank was completely rusted when we removed the engine, a thing that did surprise me was that it was not leaky! Before you start working the tank, remove the fuel level meter, seal the hole at the bottom of the tank and fill the tank with little silica bricks and diesel. Rock the entire tank to move the silica bricks around; this will loosen rust from the inside of the tank. Leave the mix in there for a few days and examine the sludge that you’ll get out of it.
The outside of the tank was sandblasted and powder coated. Powder coating is a type of dry coating, which is applied as a dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a "skin." Powder coating has several advantages over conventional liquid coatings: thicker coatings without running or sagging, high scratch resistance and overspray can be recycled, which is a good thing for our environment!
Finally we polished the (original!) tank cap using Commandant Cleaner and a polishing brush on a drill. Commandant Cleaner is a polishing compound used when normal compounds deliver inadequate results. It can be used to revive heavily corroded chrome, aluminium or pain.
