The vertical fin (upper half) is one of the easier pieces to start sheeting. I tape together several sheets of 1/16" balsa. I lay the shuck on top and trace around. Cut this out and you have a skin. Cut out an opposite one for the other side of the core. I use polyurethane glue for all of my skins. I apply the glue to each skin and spread it quite thin using a bondo spreader or similar tool. Carefully place the skins and foam parts together and cure them under pressure. I normally use a vacuum bag, but weight can be used also. If using weights, be sure your work surface is flat and strong. I recommend placing a thick piece MDF board on top of the assembly and then pile on the weight.

The same procedure can be used to sheet the bottom vertical fin/rudder piece.

Sand any overhanging balsa flush to the cores and then prepare to join the two halves. The top and bottom halves should () lay flat to one another in their shucks. I had to shim one of my halves just slightly. Apply polyurethane glue (sparingly) to one of the roots and carefully assemble back into the bottom shucks. Again, make sure the halves are aligned properly before lettting it cure...you have time with the polyurethane glue, so check. You can see in the photo that I actually taped the halves together to get my alignment just right before placing them back into the shucks to cure.