How to Build a Cardboard Solar Cooker

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How to Build a Cardboard
Solar Cooker

Here�s a great weekend project! This is a solar cooker built out of tin foil, glue, tape, and used cardboard boxes. It cost about $3 to build and it does an excellent job of cooking hot dogs. It takes about thirty minutes to cook dogs from refrigerator to bun. I also heated up 16 ounces of canned, ready-made beef stew in about the same amount of time.

These inexpensive cookers could be made anywhere in the world. People in central and South America could use them. Campers could use them as a light weight alternative to gas stoves. My cardboard cooker has replaced my conventional microwave and stove for heating meals. It isn�t as fast as a microwave oven but there�s a deep sense of satisfaction knowing that I�m cooking with renewable solar energy.

Construction:

This cooker is composed of twelve sides. The dimensions of each side are as follows:

These dimensions will produce a cooker with a rim diameter of two feet. To double the size of your cooker simply double the dimensional values.

One starts construction by using the above dimensions to build templates made of construction paper. Draw dimensions on heavy paper using a compass and ruler.

Cut these shapes out of the construction paper to produce templates.

These shapes are then used to trace panels for the cooker on used cardboard boxes. These are cut out to produce twelve of the set of three panels. There is also a 7-inch round disk that must be made for the base of the cooker. Outline this on a piece of cardboard and cut out.

Then, arrange the sides into an arch like the one below. Feel free to arrange the sides in an order that�s aesthetically appealing.

Tape the three different sized sets of panels together using wide tape.

Then tape the edges of the larger panels together to make the arch. Lay this down on a clean flat surface brown cardboard side facing up.

Now spray an adhesive like 3M 90 on the upper exposed side of the panels. Make sure the glue coats the surface completely and evenly. Roll out a large sheet of heavy duty aluminum foil and coat the least shiny side of it with glue also. Starting from one corner of the arch, attach foil to panels evenly with as few wrinkles as possible.

It may take more that one piece of tin foil to cover panels completely. Be sure not to get any adhesive on the shiny side of the tin foil. Be sure to cover the 7-inch disk with tin foil also.

While letting this dry, build the solar cooker�s stand. This can be done with some conduit pipe, fasteners, chain, and some electrical tape.

Drill holes at the base of each pipe and bolt on some kind of fastener. Then tape together the pipe in the middle with the electrician�s tape.

Attach chain to fasteners and now one has a tripod!

Cut away extra foil from panels after the glue has dried.

A cardboard fastener is made out of any piece of extra cardboard. I like to use the edge of a cardboard box where it�s already bent. This strip should be no more than two inches wide and seven inches long. Punch holes in the cardboard fastener and the two end reflective panels that are to be attached using a paper punch.

I like to use bolts, washers and nuts to put the thing together. Also paper punch holes into the centers of the smallest panels to attach to the underside of the 7-inch disk.

Use all fasteners are attached, one should have a stable, funnel like bowl. Spray a coat of protective gloss on the shiny aluminum at this point. This will keep the aluminum from oxidizing and losing its shiny finish.

This type of reflector focuses light to just above the center of the 7-inch disk�s reflective surface.

To take advantage of this, one must build a stand to place the food on. This can be done bending wire mesh into a form suitable.

Line the base of the apparatus with aluminum foil to prevent juices from spilling onto the cookers reflective surface. Place this in cooker placed on tripod and point toward the sun.

Wait no more than thirty minutes on a sunny 70 degree day for very hot dogs.