Today I had a few minutes to start spraying stuff onto other stuff related to the octagon ports.
First up, the 1/8" MDF holders. These need to be painted black in order to conceal them inside the droid.
I boldly went without primer, and hit them with a couple of coats of flat black.
Next, I cleaned up the residue that was left over from my work on the octagon port frame pieces, and masked them. They don't have to be masked, but it makes for a neater paint job to not have stray paint all over the outer perimeter.
I then applied three coats of white primer, about 15 minutes apart.
I'll let these dry overnight, and then lightly sand them smooth. Hopefully I'll have time to paint them blue in the near-future.