Making a Solar Cooker for Free

Making a solar cooker doesn't require special materials. You either have them at hand already or can easily find them.


| June/July 1994



144 making a solar cooker - woman with cooker

When you finish making a solar cooker — it should only take an afternoon — it might look something like this.


PHOTO: SOLAR COOKERS INTERNATIONAL

By now, we've all heard about solar cookers of one sort or another. And you know an idea has finally gone "mainstream" when you open a glossy mail-order catalog and find solar cookers for sale. Nevertheless, most residents of the United States still think of solar cookers as some sort of novelty, perhaps a good weekend project for Scouts, but not something that is practical and useful.

In fact, solar cooking is practical in every state of the Union (except Alaska) for at least six to eight months every year. Even with snow on the ground, you'll still be able to cook if the day is sunny. As for cost — well, I wouldn't consider purchasing a prefab solar cooker. My wallet simply wouldn't allow me that luxury.

MOTHER EARTH NEWS readers may have made their own cookers described in past issues, particularly the parabolic dish cooker, and the "breadbox" design made from wood or sheet metal. But there's an even simpler — and cheaper — way of making a solar cooker: use cardboard boxes.

First, get two boxes. One should be able to fit into the other, with ideally an inch of space all around. (If you can't find boxes, you can cut and fit your own). Now, cover both inside and outside of the little box with aluminum foil, and cover the inside of the big box with aluminum foil. A water-based glue works fine for this.

Now, placing the little box into the bigger box, the tops of each box should be at the same level. To accomplish this you need to support the inner box so that it is off the floor of the bigger box. This is done by placing small pieces of flat wood inside the big box. Generally, four small pieces of wood will serve as four "legs" to support the inner box. You can also use several pieces of cardboard to raise up the inner box. Once you've placed and glued these four legs, you pack all the space between the two boxes with crumpled newspapers. Though most people have no problem obtaining old newspapers for the insulation, you can use many other substances too: old cotton rags, straw, dried grass, coconut fibers, etc. Though you might be tempted to use white blown foam packing chips for insulation, DON'T! At high temperatures, they often melt and/or give off undesirable fumes.

Now that you have one box inside another, with both of their tops level, and with the insulation packed between the boxes, you are ready to seal the insulation. This is done simply by taping or gluing pieces of cardboard over the top open section between the two boxes.

magnar totland
11/16/2008 7:29:24 PM

Hello I have some designs of the cardboard oven. Maybe you would like to take a look. Here is the link: http://solarcookers.ning.com/photo/albums/cardboard-oven Best, Magnar Totland congo-brazzaville






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