I bought a new detail palm sander today and boy did it make quick work of the sanding. With the face well sanded I began thinking of how to attached the detail. I figured I better stiffen them first otherwise they might fold, so I did a quick polyurethane coat on the inside.
Once dried I sanded the Triforce piece to form over the shield face. I then attached it with some bondo.
As always lots of pictures in the gallery.