The “Minimum” Solar Box Cooker is a simple box cooker that can be built in a few hours for very little money. When this cooker was designed, it was named it the “Minimum Solar Box Cooker” because, at the time, it represented the simplest design we could devise. What we didn’t communicate with that name was that this is a full-power cooker that works very well, and is in no wayminimum as far as its cooking power goes.
- Two cardboard boxes. We would suggest that you use an inner box that is at least 15 inch x 15 inch (38 cm x 38 cm), but bigger is better. The outer box should be larger than the small box all around, but it doesn’t matter how much bigger, as long as there is a half inch (1.5cm) or more of an airspace between the two boxes. The distance between the two boxes does not have to be equal all the way around. Also, keep in mind that it is very easy to adjust the size of a cardboard box by cutting and gluing it.
- One sheet of cardboard to make the lid. This piece must be approximately 2 to 3 inch (4 to 8 cm) larger all the way around than the top of the finished cooker (the outer box).
- One small roll of aluminum foil.
- One can of flat-black spray paint (look for the words “non-toxic when dry”) or one small jar of black tempera paint. Some people have reported making their own paint out of soot mixed with wheat paste.
- At least 8 ounces (250 g) of white glue or wheat paste.
- One Reynolds Oven Cooking Bag®. These are available in almost all supermarkets in the U.S. and they can be mail-ordered from Solar Cookers International. They are rated for 400 °F (204 °C) so they are perfect for solar cooking. They are not UV-resistant; thus they will become more brittle and opaque over time and may need to be replaced periodically. A sheet of glass can also be used, but this is more expensive and fragile, and doesn’t offer that much better cooking except on windy days.