Waterproof and strengthen the bottom of the hull with fiberglass cloth and epoxy. Use epoxy sparingly to save weight. The hull bottom takes much abuse on takeoff and landing hence the fiberglass / epoxy treatment. The rest of the fuselage, wings and tail feathers can be covered with monokote. Make sure all seams overlap 3/8" to 1/2" and are fully sealed. Brush clear nail polish on all seam lines to insure they stay down. Hope this helps![8D]