Box-style solar ovens need three elements to function:
- An insulated box. This can be as simple as a smaller box nested inside a larger one, with cardboard pieces cut to fill the spaces between. Other insulation might be newspaper or fiberglass (but make sure the fiberglass is well contained). Paper doesn’t burn at 400 degrees, so don’t worry about that.
- A glass front to let the sun rays enter the box. Some people use old windows, still in the frame.
- Heat concentration, usually obtained with reflectors focusing the sun’s rays into the box. These can be as simple as cardboard covered with aluminum foil.
A panel cooker can be created with a windshield reflector ($3 item at the auto parts store) curved to reflect heat into a glass jar or onto a dark-colored cover pot.
These designs can be as simple or elegant as you like.
So, experiment! One friend brought to one of my workshops two boxes without any insulation between them, an old window to set on top, and NO reflectors. Without even tilting it toward the sun, we watched the temperature rise to 150 degrees in 10 minutes! So, have fun!
One of my favorite
“do-it-yourself-cheap”
box-cooker designs
is the “Heaven’s Flame” model developed by Joe Radabaugh,
which was published in
Backwoods Home Magazine.
With Joe’s permission, I’ve been handing out his instructions at my workshops. Click here to see the instructions laid up in four,