Last night I riveted the trim tab spar to the bottom skin and riveted the horn in place, and tonight I glued the foam ribs in place and riveted the top skin onto the spar.
I back riveted the spar to the skin then carefully riveted the trim tab horn in place. Unlike my first attempt I was able to complete this step without buckling the skin. It was a bit tense, and a big relief to get it done without incident. The thin skin is not very forgiving, and demands that the squeezer is exactly square to avoid cleaving the rivet over like a bent nail.
Tonight I had my first experience with tank sealant, as it’s used to glue down three foam ribs inside the trim tab. I preped all the surfaces with rubbing alcohol, then applied double sided tape to the trailing edge wedge. With one side’s backing peeled off, I located it on the bottom skin with the help of a couple of clecos. Then I mixed up the sealant, and practiced on some scrap foam and sheet aluminum. I found the sealant to be very easy to use, much like a silicone sealant, but with a far worse smell. I applied a very thin coat to the bottom of the ribs and then carefully placed then on the skin. Then applied a coat on the top, and ensured the ribs were straight.
I carefully placed the top skin on, and clecoed along the spar, then along the trailing edge and sides. Next step was riveting the top skin to the front spar, with the hinge attached. This turned out to be an easy job with the squeezer, although I almost ran out of 3-4 rivets. Finally, I weighed down the side to help the glue bond, and clecoed on some straight edges to keep the trailing edge straight.
Next step is to let this trim tab sandwich sit for a few days and then rivet the trailing edge and close out tabs.