The Haines Pop-open Solar Cooker was designed by Roger Haines, a resident of San Diego, California, USA. It works like a "pop-open" car sunshade. The cooker's unique template, thin material, and "pop-open" design permits it to be shipped and stored in a small envelope despite its 30" round diameter by 18" high size when it is "popped open." The design allows it to be stretched rigid in windy conditions, and a transparent windscreen creates "oven-like" conditions around the cooking pot.
The cooker is made from reflective plastic film (e.g. Mylar or metalized polyester) or reflective fabric). The material must be "slippery" to the touch. The material is sewn or glued to a 30" circle made of the same galvanized steel flat spring wire used to make pop-open car sunshades, e.g., .035-inch x .125-inch.
To set up the cooker, place it on a square of cardboard (to make it easy to turn to follow the sun during the day. Put a 9-inch by 16-inch rectangle of rigid reflective material (Mylar taped to cardboard will do) on the flat bottom in the center of the cooker and put a black cooking pot on the rectangle (preferably in a Haines cooking sleeve). Grab the edges of the cooker (i.e., the edges of the wire circle) and raise the edges until the reflective film is stretched tight.
In the morning or evening when the sun is low, move the pot closer to the front of the cooker, and tilt the cooker forward, lifting the back until the front touches the ground. To make it easier to lift the back of the "bottom" of the cooker, replace the 9" x 16" thin reflective rectangle with a 3-sided 9" x 16" wire rectangle to hold the bottom of the cooker rigid as it is tilted up, while allowing the cooking pot to remain flat on the ground.
The sides of the reflector (the wire circle) can be supported by any material at hand (e.g., sticks, rocks, or triangles of plastic or cardboard). The flaps on the bottom of the cooker can be held down with bricks.
The windscreen is made of transparent UV-resistant plastic film sewn or glued to a 30" wire circle (the same as reflector wire). The windscreen is secured to the reflector with binder clips or clothespins to create "oven-like" conditions during cooking.
To store the cooker or sunscreen, bring the two sides of the 30-inch circle together and gently twist. If done properly, the wire will "automatically" twist itself into a 10-inch circle (do not force, or you will bend the wire). To re-open. simply allow the material to "pop-open."
Alternatively, the cooker template can be used to make a cooker out of more rigid materials, such as reflective bubble insulation or reflective foam insulation.
- See Roger Haines.