Tonight I glued in the foam ribs on both elevators. I mixed up a batch of tank sealant, then applied with a gun and a popsicle stick, getting a smooth even coating. I started with the left elevator, then the right, and then weighed down the top skins to ensure the skin stays in contact with the ribs while the sealant cures. I’ll let these sit until the weekend, then can start riveting the trailing edges.