Introduction: How to Make a Wonder Box Cooker/Cooler

About: In a valiant attempt to keep myself from dying of boredom, I create.
A few years ago a friend showed up at a gathering with a frozen lemonade pie that had traveled quite a long distance and was still frozen solid.  “How?” was asked and the reply was “My Wonder Box”.  That was my first introduction to the Wonder Box Cooker/Cooler.  It was designed for the people in Africa who do not have enough fuel to cook their food.  Once a dish is hot, it can be moved to the Wonder Box and about 4 hours later, with no additional fuel expended, the meal is cooked.  It also works to keep cold things cold, and warm things warm.  Think how useful this would be if there was no electricity for an extended length of time.  Just use your BBQ grill to heat up the pot of food for 10 to 15 minutes and then stick it in the Wonder Box to finish the cooking.  The box holds the heat in to the pot using it to cook the food instead of the heat escaping into the air, and then having to use more energy to create more heat to cook the food. Here is how to make your own Wonder Box Cooker.

Step 1:

Pattern for the Wonder Box (You will need heavy paper, a protractor (a paper one can be found here:, a pencil, a ruler, and paper scissors to make your own copy of the pattern from the one found here: ( this one is no longer there, try this one:
3.5 yards material (100% cotton)
Sewing machine
Sewing scissors
Fabric weights (pattern found here:
Straight pins
+/-12 gallons Polystyrene Pellets (bean bag filler, check the web)
Large piece of paper (to make a funnel not shown)
Empty 1 gallon ice cream bucket (not shown)

Step 2:

Print off the PDF that has the dimensions of the pattern pieces needed (there are only 2 pieces).  Using the ruler and the protractor, create a full size copy of each piece.  This took me longer than the cutting and sewing of the box.  Write “cut 4 pieces” on each pattern piece.  The small piece is the lid and the larger odd shaped piece is the body of the box.

Step 3:

Lay out your material, and layer it 4 layers thick.  This means you only have to cut once to cut our all four pieces.  Lay out the lid pattern piece on the material. Use the pattern weights to hold the pattern in place.  Cut out the pieces.

Step 4:

Repeat with the box body pattern part.

Step 5:

Set up the sewing machine.  Take two pieces of the lid and place them right sides of material together.  Pin one side together, from a point down a side and around to the point at the other end.  Repeat the process with the other two pieces. Sew each of the 2 pieces together with a ¼ inch seam.  Now take the two completed halves, open them up and pin them together point to point and then all the way around with a ¼ inch seam,

Step 6:

leaving a 6 inch gap in one side.  This is the place where you will turn the lid right side out and be able to put the polystyrene pellets into the lid.  Turn the lid inside out.

Step 7:

Repeat the process with the pieces for the body of the box.    The wide pointed end when all put together is the outside bottom of the box.  The narrower pointed end is the inside bottom of the box.  Again, leave a 6 inch gap in the bottom for the turning of the box right side out and the adding of the pellets.  Turn the box inside out.

Step 8:

 These are the Polystyrene Pellets, I bought from a friend. Her husband owns a business that has access to these wonderful little pellets. The bag I bought has enough to do 4.5 Wonder Boxes. One day my kids will each get one of these for Christmas.

Step 9:

This next part is a two person, outdoor, activity.  You need one person to hold the paper funnel into the opening in the lid.  The other person scoops the pellets into the fabric lid.  You don’t want to stuff it full.  You need it to be flexible to fit about different shaped objects.  It will take 4 or 5 gallon ice cream buckets of pellets.

Step 10:

Repeat with the body of the box. It will take 6 or 7 gallon ice cream buckets full of pellets.  Use straight pins to pin the openings closed.

Step 11:

Return to the sewing machine. Tuck in the edges of the opening and sew the open seams closed.

Step 12:

Take a moment tuck the inside end of the box into the center of the box.  This is the area that the pots, etc. will fit into the center of the box.  So you put the object you want to keep hot or warm or cold in the center and cover it with the lid.  This thing really works.

Step 13:

This is how to use your Wonder Box Cooker/Cooler. First fill a pot (that doesn't have a long handle) almost full with what you want to cook and enough water to cover it.   Bring the pot (with it's lid on)  to a boil and let it boil for 10-15 minutes.  Do not remove the lid, you will loose too much heat. 

Step 14:

With hot pads transfer the pot to the Wonder box and fluff up the sides so that they come in contact with all the side of the pot. 

Step 15:

Place the Wonder Box lid on top of the pot.  And let it set undisturbed for 2-4 hours. 

Step 16:

I opened this box after 2 hours and the potatoes were done. Can you see how useful this would be if you are in situation where there is no electricity.

Step 17:

So, this is the Wonder Box Cooker/Cooler. I use it a lot in my everyday life, so that when the emergency situation does come, and it will, I will think of it and use it, to keep my family fed. Enjoy!
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