Depends on the material. Your typical "home" 3D printer will not print using materials that can withstand weather, heat, moisture. There are some good plastics such as nylon and ABS that can be printed. Metals can also be printed. But all of these are done with industrial type printers. Your best bet is to get the design perfected, then send off your stl model to a company like Shapeways for printing in your choice of dozens of materials.
