Make a Cardboard Box Reflector Oven

There's no surer way to impress Cub Scouts with outdoor cooking than to tell them you're going to bake their favorite treat in a cardboard box.

As outdoor cooking methods go this is more stunt than practical, but it does pique the interest of young Webelos and their parents and is actually quite easy to pull off. We usually make the oven in a den meeting, and cook in it the next week as part of our Outdoorsman activity badge.   Here's how you can make one:

Cardboard Box Oven Tools and Supplies

• One cardboard box - approximately 22" x 15" x 11" 
• Aluminum foil - Have a full roll on hand, although you may not need it all
• A few heavy wire coat hangers
• 1/4" light-duty staples (for a staple gun) separated from each other
• Duct tape
• 2 disposable aluminum pie plates
• A utility knife or heavy scissors (for cutting cardboard)
• A pair of heavy wire cutters or lineman's pliers

Making the Oven
1.       Start by cutting one of the short flaps on the open end of the box down to 2-3 inches.  This will be the top edge of your reflector oven.

The short flap will hold your doors closed.

2.       Cover the inside of the box with layers of foil as follows:

A.     Bend a short piece around the four corners of the side walls, a small amount should also overlap the back wall of the oven.  Secure by pushing staples through the foil by hand at an angle.

B.     Stretch long pieces from the outside of the short (top) flap to the outside of the opposite flap, carefully tucking the foil into the corners so that the entire top, back, and bottom of the oven are covered and about 3" of foil are wrapped around to the outside of the oven.  Be sure to overlap all pieces and leave no cardboard exposed.  Inside, attach by pushing staples though by hand.  Outside, secure the ends with duct tape.

C.      Stretch pieces from the outside of one long flap to the other long flap (side to side) being sure to overlap your pieces.  Tuck carefully into corners and secure with staples inside and duct tape outside.  The entire  inside of the box should now be covered in foil.

There should be no exposed cardboard inside the oven.

3.      Create a baking shelf about 1/3 of the way down from the top by straightening and cutting wire coat hangers into straight pieces and pushing them through the box from left to right.  Use a ruler to ensure that the shelf is the same distance from the top corner on each side and your baking pan is level.   Bend the ends of the wires to hold them in place.

4.      If the wires sag, you can strengthen the shelf by weaving a couple of additional wires from front to back of the oven through the wires installed in step 3.

The baking rack in the carboard box oven is
made with coat hangers.

5.  Place one pie plate upside down at the base of the oven, and the second one right-side up on top of it.  This will hold the charcoal briquettes that are used as a heat source.

The lower pan keeps the extreme heat from the briquettes
away from the flammable cardboard box oven floor.

6.  Close your long side flaps first, and use the shortened top flap to hold them closed.

Exterior of the completed oven.

You have a completed Cardboard Box Reflector Oven!

Baking in the  Cardboard Box Oven

In theory, you should be able to bake just about anything in this oven, with the only constraint being the oven's small size and lightweight construction, which will by no means support a heavy load.  I usually opt for simple items that are easy for the scouts to make, like brownies or cornbread from a pre-packaged mix. 

You may need to experiment with the heat, but usually I find that 4-6 briquettes preheated until they are mostly white are about right for 350 degrees on a New England summer day. Preheat these outside the oven and then place these in the top pie plate and your baked goods on the rack in a disposable foil pan. A small shovel can be used to transfer preheated coals into the oven.