Set up the #40 countersink for the tank cap flanges. Initial setting was for rivet head flush, then incrased depth to .007 deeper per plans Section 5. Checked countersink depth with a scrap piece of .032 sheet that I had dimpled to be sure countersinks were sufficient for flange to rest on skin. Proceeded to countersink all holes on left and right tank flanges. Cleco'd them to the skin for a test fit. Removed and scuffed mating surface with scotchbrite.
Washed all tank parts in warm water using Dawn dish soap as I do when preparing to prime. Wore gloves to not touch any surfaces. Set parts out to air dry.
Removed blue plastic from inside of right tank skin. Washed and air dried skin.