Lift the books next morning, take a few minutes to recover, and then check the fin; what do we find?Not warped, not wrinkled, paper’s sticking down. But it’s a bit stained from stuff on the workbench. Lesson learned: Work on a cleaner surface. I don’t expect this to be visible after priming and painting, though.
I put a droplet of yellow wood glue between paper and balsa on both sidessqueezed the corner and wiped off the excess glueand sandwiched the fin in wax paper before applying the heavy weight again. This time I focused the weight on the fin by putting a wood block, a little larger than the fin, between the fin and the books. Don’t ask me why I didn’t think of that last night.
Now we wait some more.