Dave sent this link in, the solar cooker plan site. Some easy ideas on how to build your own cheap solar cooker.
Here are a few advantages of why you might want to:
a) No fuel for cooking. Solar cookers are independent of fuel sources, including wood, electricity, natural gas or propane. Save those resources for night time use.
b) Portability. They’re easy to move comparatively speaking to an oven, or barbecue or cookstove. You can even take one of these with you while you camp out at a road block, pleading to be let in. But if you’re really creative, you’ll use the mirrors to blind the guards and steal their food (at your own risk of course).
c) No smoke. There is no tell-tale sign of smoke, giving away your location. You’ll still have to deal with the savory smell of your home cooked dehydrated food sizzling away attracting hungry zombies (and flies). Windless days are best, so plan your meals accordingly.
d) Low cost. These things are cheap, if you want them to be, or they can be commercially bought. Make your own out of any reflective surface and cardboard (higher reflectivity, the better), or build better using more durable materials (non-flammable framing materials and mirrors if you like). You lose easy portability, but hey, stay home and repel zombies from the comfort of your couch.
e) They work best on bright days, but even hazy days with cloud cover they work ok and can get pretty hot. Angle the reflective panels for best exposure to the sun, and you may also want to rotate the cooker to account for the Earth’s rotation.
f) Cooking time is dependent upon temperature, solar exposure and the foods you are preparing. Making hot water is pretty easy though.
g) These things can get HOT, so don’t handle them carelessly. You will need a mitten or something to remove lids or pots. Cast iron works pretty good, but it’s heavy and hard to handle. Big advantage here is the durability of cast iron and absorption and retention of heat (recommended).
The principles behind solar cooking can also be applied to making your own hot water heater for heating your home (or simply taking a hot shower in the sticks). I’ve seen solar hot water panels installed in the sides of metal buildings for example, providing plenty of solar heating even in snow country.
I’ve got one, bought it from Savinar before I knew he was a greedy arrogant bastard. The cooker works just fine, even on a cloudy day. It’s big and bulky and that is the only real drawback to this particular design. I’m going to repel zombies from my watchtower while the cooker makes my lunch.
You can make your own cooker that folds up pretty flat by following the plans linked above. Pickup one of those aluminized windshield shades at a garage sale for a nickel and experiment.