Sheeting being test-fitted in one part of the wing mold

Square cutouts are raised areas in the mold where the aileron bays will be. This makes an indent in the wing where the servo hatch will fit. I used a piece of 1/16" abs plastic that is double face taped to the mold. Really thin, what looks like scotch tape that has adhesive on both sides is used to attach it to the mold. The strip cutout is where the bottom gets a recess too. I use layers of trim tape to build this up.