Gluing up the plywood flap horn. The plywood flap horn is laser cut and included in the sheet of plywood parts. Cut a piece of 1/8 x 1/4" spruce as shown in the below picture to the proper length, mix up some epoxy, take a toothpick and apply some epoxy inside the square hole on the ply horn and mark the center point on the length of the spruce stick, slide the horn over the stick and let dry. In the next set of pictures I will show you how the horn is glued to the flaps.