How to Build a Solar Oven

Image Gallery You don't need your kitchen to cook! Instead, build this DIY solar cooker and use the power of the sun.  PHOTO: D.S. HALACY, JR.

©1959 by D.S. Halacy, Jr., and originally published by the Macmillan Company as a chapter of the book, Fun With the Sun. Reprinted by permission of the author. 

The "greenhouse" effect is well known to those who grow plants in such structures and also to those of us who have left the windows of an automobile rolled up on a warm, sunshiny day. The rays of the sun go through the glass well enough, but the reflections of longer wavelength are unable to bounce back out of the car. The result is aptly described as resembling an oven. And that is just what we're going to build: a solar oven that will do a real job of cooking on a clear day, even in winter.

One aim of solar scientists is to provide a means of cooking for those countries in which fuel is scarce or expensive. Dr. Maria Telkes, a well-known experimenter in the field, has designed such an oven, which she feels might be mass produced at a reasonable price. Our design is copied from the Telkes unit, which has been demonstrated in foreign lands.

Basically the solar oven consists of a box for the food and a glass cover to admit and trap heat inside the container. The box shown is made from galvanized iron but could as well have been aluminum for lighter weight. The reflector panels are of aluminum.

Besides the sheet metal parts, we need a piece of double-strength window glass, a sealing strip for the pane and 3 handles. We will insulate the box with spun glass material 2 inches thick for greater heat retention.

Materials
16 square feet of 28-gauge galvanized iron
24 No. 6, 3/8-inch sheet metal screws
12 square feet of 2-inch fiberglass insulation
22-by-24 inches of double-strength window glass
3 drawer pulls
On spray can flat black paint
6 2-inch roofing nails
8 feet of sealer strip
4 pieces of .025-by-22-by-24-inches aluminum sheeting
4 small turn-buttons with installation hardware  

Directions
It will be a good idea to have all materials on hand before beginning the project. One exception could be the sheet metal for the box, in case you decide to let your local sheet metal shop do the cutting and bending for you. This is a good idea unless you're familiar with metalwork, and will result in a more professional job at little additional cost.

If you want to do all the work yourself, and feel that you can handle the job, this is the way to begin:

Construct the bottom of the oven: The bottom of the oven is a rectangle of metal, with the corners notched out to allow bending up flanges all around the sides. These are 3/4-inch flanges and they're bent up 90 degrees, except for the front edge, which is a closed (acute) 45-degree angle, one inch long.