For a reference about the weight of metal speed brakes, my speed brake is made of 1/4" five-ply plywood and is 7.5 inches by 30.5 inches. I covered it with glass on both sides. With the piano hinge attached for mounting, and with paint, it weighs 2 pounds 1.6 ounces (953 grams). It will be actuated by a car seat slide and motor.
Hindsight is always 20/20. If I were to do it again, I would use a sheet of 1/4" Last-a-Foam with reinforcement at the attachment for the actuator arm. Jim Vance va...@claflinwildcats.com
