How-to: Make a panel solar cooker
By CG Lifestyles & People Editor Neal Patten
Summer is great for a range of outdoor activities from swimming and hiking to camping and picnics. For many, the best part of the season is preparing food outdoors. Campfires and grilling are great but have you ever tried cooking with good old Mr. Sunshine? For this week’s how-to I will show you how to make a homemade panel solar cooker using items from around the house. This is a low-cost, easy project that just takes a little TLC.
You may even find your food tastes better thanks to the slow cook process. This process allows more time for complex carbohydrates to break down into simple sugars, infusing your food with more natural sweetness. Now that’s cooking with science!
Your total assembly time will be around 2 to 3 hours.
1. Here’s what you need to get started:
- A 36 inch by 48 inch sheet of cardboard (go dumpster diving or solicit local businesses)
- Large sheet aluminum foil (regular is preferred but heavy duty will also do the trick)
- Boxcutter or shearing scissors
- A yardstick or other straightedge tool
- Large spoon
- Measuring tape
- 6 ounces white glue
- Container for mixing (recycle an old butter tub!)
- Oven bag
2. Lay the cardboard on a flat surface, the long side horizontal. Using your measuring tape penil in marks (along the top edge of your cardboard) from left to right at these measurements: 4.5 inches, 17.75 inches, 20 inches, 27.75 inches, 30 inches, 43.5 inches. I suggest you make the same markings along the bottom of the cardboard and then use your straightedge to connect them accurately.
3. On the vertical edge, from bottom to top, pencil in marks at 11 inches, 17.25 inches, 22.5 inches.
4. On the left side, at the intersection of your 4.5 inch vertical line/11 inch horizontal line and from the point where the 17.25 inch horizontal line meets the left edge of the cardboard, draw a line to the intersection of the 20 inch vertical line and 22.5 inch horizontal line.
On the right side create the mirror image by connecting lines to the 27.75 inch vertical/22.5 inch horizontal intersection from 43.5 inch vertical/11 inch horizontal and from right edge 17.25 inch horizontal.
5. Cut away the pincers you just made.
6. On both sides measuring from the edge over draw vertical lines at 1.75 inches and 4 inches up to the 11 inch line. Draw a horizontal line 7 inches from the bottom over to the 1.75 inch vertical line.
7. From the 11 inch horizontal line to the intersection of the 1.75 inch vertical/7 inch horizontal lines cut a slit as wide as the cardboard is thick.
8. From where the 17.75 inch vertical line meets the top of the cardboard to the intersection of the 20 inch vertical line/22.5 inch horizontal line draw a diagonal line. Symmetrically you will create another diagonal line from where the 30 inch vertical line meets the top of the cardboard to the intersection of the 27.75 inch vertical line/22.5 inch horizontal line.
9. Using your straightedge tool for precision, make slits along the diagonal lines you just made. Also make serrations along the 22.5 inch horizontal line that connects the diagonals. Leave spaces so that you do not cut clear down the line. Finally, make intermittent cuts along the entire 11 inch horizontal line. Now fold inward along each line, then outward repeating several times to make the board flexible. Lay everything flat again.
10. Mix the six ounces of glue with 24 ounces of water and stir until there is no solids. Get out your foil, paintbrush and a pair of scissors. It is time to begin covering the cardboard with the foil.
11. Working one panel at a time, liberally paint glue onto the cardboard surface and cover with large sheets of foil. The shiny side should be applied to the cardboard, leaving the dull side revealed. This may seem counterintuitive but the dull side actually diffuses the heat better.
12. As you work, use the flat side of the wooden spoon to smooth out wrinkles in the foil and help make sure it binds to the cardboard. You may need to cut off excess foil from the edges or wrap it around to the other side and secure by stapling. Re-expose the slits by slicing the foil with your boxcutter.
13. Once everything has been left to dry for a few minutes, it is time to fold the panels into place. start by folding the horizontal 11 inch line up, which creates the base for the cooker. Now fold each of the diagonal flaps in. Fold downwards along the 22.5 inch horizontal line. Slip the corners of each diagonal flap into their respective slits. If it fits snugly, you’re done! If it seems loose, take two or three paperclips and stack them on top of one another on the rabbit ear underneath the slit, which will keep the corner from slipping back up through the slot.
14. Use a dark cooking pot. When cooking, you will need to place the pot on top of an insulating spacer. A brick works great for this. The whole ensemble must be sealed within an oven bag.
- Just in case you had your doubts, this is a real form of cooking, handle your pot with oven mitts.
- Do not leave your panel cooker outside for extended periods of time, the reflective surfaces can create fires. Also it will save it from getting ruined in the rain.
- Wear sunglasses while cooking.
- Cardboard works just as well as any other material for a panel cooker. Temperatures will max out around 300 degrees.
- An oven thermometer will help you gauge the temperature of your cooking vessel so you never over or under cook your food.
- Be aware of your surroundings, typically your panel cooker should be safe from animals – raccoons, squirrels and other such critters know not to mess with hot surfaces. Bears, on the other hand, are not so smart.
- To speed up cooking time, rotate your cooker every half hour to follow the path of the sun. This also prevents hot spots from forming that may scorch a portion of your food.
- If you can make it in a crock pot, oven or on stovetop – you should be able to cook it in your solar panel cooker! The process is that effective that you should not find yourself being prohibited.
For detailed diagrams of the plans above, consult Cooking with Sunshine by Lorraine Anderson and Rick Palkovic (De Capo Press, 2006). That is where I derived these instructions from. The book is also filled with over 100 delicious recipes that will be sure you give your solar panel cooker quite the workout.
The sun is such a beautiful heavenly body. We rely on it for warmth to live, energy for plants to grow, Vitamin D for healthy immune systems, gravity to keep our planet in place – and it can even produce energy for powering our world and cooking our food. Appreciate the power of this ancient star!