The Sun-Funel cooker is similar to the Fun-Panel cooker, but with a different panel fold. The revised panel fold is necessary in order to form a rigid cooker base that is strong enough to support the cooking pot in an elevated, but more advantageous, position.
A stick, which traverses the lower section of the cooker, is added so that the cooking pot can be placed as horizontally as possible, even after the cooker has been repositioned at a different pitch angle. This means that the cooker and the pot can now be easily repositioned to track the sun's movement for a more efficient cooking throughout the day.
The cooker can be constructed, in less than an hour, from a used cardboard box, a stick, some aluminum foil and some homemade glue. The plan and the construction steps for the Sun-Funnel cooker are as shown below.
Step 1 - Obtain two pieces of cardboard from a used cardboard box. Cut them to the dimensions as specified in the plan.
Step 2 - Glue aluminum foil on the two p[ieces of cardboard. First lay the foil on a clean flat surface, then spread glue on the foil. Align and lower the cardboard on the glued foil. Press down to make the foil stick to the cardboard. Trim off any excess foil around the edges of the cardboard.
Step 3 - Draw the fold lines on the two pieces of cardboard and indent the fold lines with a straight edge. I use a short piece of metal angle to press down on the fold lines in order to make sharp and deep indentation lines.
Step 4 - Deep and sharp indentation lines produce much better and cleaner folds later on. The photo below shows the properly indented lines on the cardboard.
Step 5 - Bend the two cardboard pieces to form two L-shaped panels. Join the two L-shaped panels together, as shown in the photo below, using store bought tape or tape made from cardboard strips and glue.
Step 6 - Spread open the two sides of the joined cardboard panels to form the desired funnel shape. Make sure that all fold lines are evenly bent to form an even funnel shape.
Step 7 - Make two through holes on the lower side walls of the cooker. Insert a stick through the holes. Both ends of the stick should protrude slightly out of the cooker. The construction of the cooker is now completed.
The size of this Sun-Funnel cooker is suitable for use with a 4-liter size black metal pot that has a tight fitting clear glass lid. A plastic oven bag can be used as a green house enclosure for the pot if a black metal lid is to be used instead of a clear glass lid or when a higher cooking temperature is desired.
The following illustrations show the various pot arrangements and cooker positions in order to best capture the sunlight.
The photo below shows the Sun-Funnel cooker in the low sun-angle position. The pot is supported by the stick at the back and a small piece of cardboard wegde at the front.
The photo below shows the Sun-Funnel cooker in the medium sun-angle position. The pot is supported by the stick at the back and resting against the cooker panel at the front.
Just click on the link below for a pdf version of the Sun-Funnel cooker construction plan, which you can download for easy reference and distribution. You are free to distribute and share this Sun-Funnel cooker construction plan, in its complete original form, for non-commercial purpose only.
Below are links to youtube videos, whcih I have uploaded, showing water boiling and pot temperature attained with the Sun-Funnel cooker.
10 Dec 2011