This inspired me to build a solar oven, I mean, if my car can get that hot, just imagine if heat was actually the goal.
I built this http://www.instructables.com/id/CERC-Green-Solar-Oven/, which worked incredibly well (325 degrees F) but I feel it's severely limited by the use of tinfoil as a reflective surface.
I decided CDs would be a perfect substitute, they are more reflective, and I happen to have tons of them lying around. But my goal had never really been to create a solar oven, just to create heat from sunlight. So instead of improving my solar oven, I decided to build a parabolic solar concentrator.
Step 1: Materials
Corrugated is harder to cut, thin cardboard will make it more difficult to attach the mirrors*
(I used a thin corrugated cardboard)
-Tape or Glue
Tape will partially cover parts of the mirrors, cutting down on the actual light reflected, but it allows for the mirrors to be more easily removed and adjusted
-Box cutter/X-Acto Knife
*The mirrors are actually just pieces of the CDs, but it's easier to refer to them like this
Step 2: Preparing the CD Pattern
-Rotate 90 degrees, repeat.
-Connect the endpoints of the pairs of parallel lines
You should end up with 4 squares containing only reflective surface, nothing clear, a square in the middle, and some arc shaped pieces.
Only the first 4 squares are important.
This CD will become your guide for cutting multiple CDs at the same time.