How To Build A Teardrop Trailer/Hatch Hinge
Hatch Hinge 
For our simple teardrop we will use a novel hinge. The hinge is called a "Harsh-Environment Plastic Piano Hinge" and is available from McMaster-Carr on the web. This is a very durable 2" wide hinge that is waterproof and can be fastened simply by driving wood screws through it (I used the same screws as for securing the luan). The process is simple enough:
- Obtain 2 pieces of 3/4" x 1/8" x 48" aluminum and drill holes every 6 inches for the wood screws.
- Position the hatch in the desire location.
- Place the plastic piano hinge in place.
- Place the aluminum strips in place and drive wood screws through the plastic hinge into the body and hatch.
- Caulk around edges.