A solar oven, when built according to the simple directions, is a low-tech but effective method for cooking food. Solar ovens get hotter faster if the surface area catching the rays of the sun is larger and if the cooking pot or pan is insulated by trapped air during the cooking process. Building a working solar oven is accomplished with parts found at the grocery store, or even with “found” parts.
Things You'll Need
- Box with lid
- Marker, black
- Box cutter
- Clear plastic, laminating or weatherizing types
- Duct tape
- Aluminum foil
- 2 sheets construction paper, black
- Oven thermometer
- Clear tape (optional)
Building a Simple Solar Oven
Place the box on a flat work surface with the lid on.
Measure from the two side edges and bottom edge of the lid 1 to 2 inches in toward the center of the lid and mark this area with a black marker on all three sides. You will have drawn three sides of a new square, with the top surface of the box lid forming its top.
Cut along the three lines with a box cutter. This is your reflective surface, which folds up from the lid.
Place the lid so the underside is exposed. Cut a piece of clear plastic 1 to 2 inches larger than the hole you just made. Ideally, you want to use a stronger clear plastic such as laminating plastic or the clear plastic used to weatherize windows in the winter. If you do not have either of these types of plastic, then you may use clear plastic kitchen wrap, although the laminating and weatherizing plastics will be sturdier and easier to manipulate.
Secure the plastic to the underside of the lid, taking care to completely cover the hole. Tape the sides of the plastic down at or close to the inside edges of the inside of the lid so that no air is able to escape from any of the plastic's edges.
Turn the lid back over and fold back the flap. Glue the aluminum foil so that the foil completely covers the flap.
Put glue on the bottom of the inside of the box, spreading it out into a thin layer. Cover it with aluminum foil from edge to edge, making sure it’s as smooth as possible. Although you want to spread the aluminum foil edge-to-edge, if the foil curls slightly at the edges, this is acceptable, as the edges of the foil do not need to form an airtight seal.
Glue one or two pieces of black construction paper to the bottom of the box over the aluminum foil. You want the area of the bottom of the box to be almost completely black, so that when you look through the plastic, that is all you see. It is not necessary to make the bottom black from edge to edge, but close to it.
Place the oven thermometer in the bottom of the box near the top edge so that you can read the temperature through the clear plastic. Securing it in place with duct tape is optional. Put the lid back on the box and you are ready to start using your solar oven.
Tips & Warnings
- During the construction process, be sure to flatten out the surfaces you cover in plastic or aluminum foil so there are as few bubbles in them as possible. This helps the sunlight to focus on the box at a direct angle and creates a hotter focal point in the center of the cooking area. You can use clear tape rather than duct tape, if you prefer.
- Never look into the center point of a solar oven without sunglasses or for more than a few seconds. Always use oven mitts to remove containers from the solar oven, as they will be hot to touch.
- Photo Credit empty brown box with lid image by nTripp from Fotolia.com