How to Build a Box Solar Cooker

What You'll Need
Two cardboard boxes, one smaller than the other
Old Newspaper
Mylar sheets or Aluminum foil
Razor knife
Non-Toxic glue
Black spray paint
Measuring tape
A black pot
Face mask

A box solar cooker is a device that focus the sun’s heat energy at one point to heat an object or structure. Solar cookers use this focused heat energy to cook food – a function that can be very useful for making a meal when conservation is the goal. The process, being fairly easy, is outlined below.

Step 1 – Take Appropriate Precautions

The reflective surface is composed of Mylar or Aluminum sheets and needs to be cut into strips to be applied correctly. Make sure that the razor knife is used with caution to avoid injuries. Always use a flat metal object to apply the adhesive to the Aluminum foil and black chart paper. This ensures that a uniform layer of adhesive is applied and prevents wetting of the paper. When using the spray paint always wear a face mask so as to avoid respiratory trouble. After going over these precautions, move on to the next step of prepping the cardboard boxes to be used as a cooker.

Step 2 – Prepping the Cardboard Boxes

Use a razor knife to cut off a quarter of the larger box from the opening. Use a measuring tape to make proper measurements before cutting so as to ensure a proper finish. Again, make another mark half way between the start and end of the box and cut only the corners along the length of the box so as to end up with a box and four flaps attached to the sides. Use a measuring tape to measure the depth of the box and cut the smaller box to a length that coincides with the depth of the larger box. Try fitting the smaller box inside the larger box to ensure that they fit perfectly and the smaller box doesn’t protrude outside of the outer box. After double-checking your work move on to sticking the aluminum sheets as depicted by the next step.

Step 3 – Applying the Aluminum Strips

Use a razor knife to cut 2-inch strips of Aluminum foil or Mylar sheet and apply to the flaps of the outer box. The sheet is first cut into strips so as to allow more control in the application process. Apply non-toxic glue using a flat metal object and stick the strips on the box using your thumb to flatten any air bubbles or wrinkles that might form. After you are done with the flaps, apply a single sheet on the base of the smaller box and you’re done with applying the reflective coating.

Step 4 – Spray Painting the Smaller Box

With your face mask on, spray paint the sides of the smaller box black. Make sure that a layer of newspaper protects the Aluminum sheet, which was installed in the previous step from the paint and that the can is held approximately 12 inches away from the sides. Spray on a fine coat of black and leave to dry. Remove the newspaper after the box has dried and move on the next step.

Step 5 – Finishing Up

After inserting the two boxes into each other, stuff the sides with newspaper for insulation. Place the food to be cooked inside a black cooking utensil such as a pan or casserole dish, and place in the smaller box. Place a piece of glass that perfectly fits the opening of the small box. Place under sunlight to cook your food.