A reflector oven is a great addition to any campsite. It will allow you to use the radiant heat from your fire to bake or slow cook any number of recipes and greatly add to meal-time appeal in the middle of nowhere. You can make a reflector oven at home, then pack it along with you. They can be quite bulky, so here is how to make one that is small and lightweight.
Label the smaller end sides of your shoebox "T" (top) and "B" (bottom). This will help you follow these directions. The floor of the shoebox will be called the "back" and the two long sides will be referred to as that. When you are done, stand your box up like a skyscraper with the open side of the box facing you.
Measure and mark 6 inches down from the top of your box on the back side. With a ruler, draw a line on the side of each box from that mark on the back to the outer corner of the top. You should have a line angled up from the back to the front top corner when you are done.
Cut along the line on each side with a box knife to separate the top from the sides.
Make a fold in the back of the box to allow the top flap to come down and meet the angle of the sides. You should be able to make the top come down like the roof to a lean-to to meet the sides. Straighten out any original folds or bends in the box to allow the top to lay as flat as flat as possible on this new angle. Use duct tape to attach the top in its new position.
Measure the depth of your reflector oven from the back to the front edge of the sides. Transfer that measurement to the old lid of the box, and cut a piece that is equal to the measurement (6 inches, for instance) but so your piece still has the reinforced bent edges of the original lid. In other words, from the top of the lid, measure down 6 inches on each side and draw a straight line between the two marks. Cut the piece out, and you now have a piece that has the end fold of the lid and two side folds that is as wide as your oven and as deep. This will become your baking shelf.
Cut three additional pieces from the old lid that are 1-inch wide and the width of the original box. Tape these pieces to one side of the piece you cut in Step 5; space the additional pieces evenly. These will help reinforce your baking shelf.
Measure up 4 inches from the bottom of your box on each side and place a mark. Insert your baking shelf into the box so the top of the shelf is level to the marks and the bent edges meet the sides and back of your oven. This will push the sides of your oven out a bit, but that's okay. Tape the baking shelf to the oven on each point where the two pieces meet.
Cover the entire inside of your oven and baking shelf with aluminum foil, shiny side out. Use one continuous piece of foil, and form it to the contours of the oven. Use duct tape to secure the aluminum foil on the outside of the oven only. Cover the entire oven, then do it again so you have two layers of aluminum foil; again, no duct tape should be exposed or placed inside the oven on top of the foil.
Place your reflector oven near your campfire so the interior of the oven is reflecting the flames.
- Claude H. Miller (via Project Gutenberg OpenSource)