Is the trunk of your car a little lacking? Try building your own car-top cargo box. This plywood project could support a maximum of 250 pounds on the car roof. Exact dimensions depended on the size of your car. We suggested cutting the sides and ends to size, and curving the ends to the roof, before curving the ribs and rails. The last step would be installing the bottom of the box and adding the railing at the top. We also recommended acquiring hooks and loops from boat shops. To attach the box to your car roof, you would slide it across the top of your car using cloth pads beneath rubber suction cups. Using wax paper between the cups and the roof of your car would also ease removal.
Read the full story in "Car-Top Carrier For Vacation Luggage"