Here I am preparing the hinge and spar with captive nuts. The nuts are bonded onto the spar and a small pin driven into the spar ensures they do not rotate.
In this one I have cut reliefs for the captive nuts. I protected the back of the nuts with a little sealer to stop the flox from getting inside. I will be cutting away most of the triangular portion of the ribs to lighten them up. they were there to ensure the flap was mounted accurately.
Hinge mounted to wing with packing to allow for the final thickness of glass. I am going to apply 2 layers of bid over the flap surface and wrap it around the hinge spar to ensure a strong mounting for the hinge.