I was too worried about catching cardboard on fire so I made mine out of sheet metal. You can get it at home depot. It comes in a roll so it will already have a parabolic shape perfect for reflecting light. Just slap some mylar or whatever on it and it works great!
partcleguy Reviewed by partcleguy on . Reflector question Trying to make a reflector out of cardboard box and foil. Would that be possible? Here is the picture of how I want it to look like. Rating: 5