Back in the 1970s there used to be an Irish beer advertisement on television where a native son was working in Saudi Arabia and sent home a postcard saying: “Sure, it’s so hot here you could fry an egg on the stones”.
As teens in a cold climate we used to think it was funny that anyone thought they could actually fry eggs on stones. But just as early ancestors worshipped the sun, in these days of high fuel costs, people are turning back to the sun as a major untapped source of energy.
Browsing the Internet one evening, I came across a website selling solar cookers for around $150, and wondering why they were so cheap, I started looking more deeply into how they work. That led to instructions on how to construct one, which looked too easy to be real.
Cardboard, tinfoil, newspapers, glass and sticky tape? That’s it?
Now, I’m no tree hugger but the doomsday mentality in me thought it would be great to have something like this when the world is eventually forced to return to the agrarian lifestyle.
The only other problem would be my lack of abilities in the DIY department, even with cardboard boxes, but the opportunity to at least have a go was too good to pass up considering the benefits and low cost involved.
I did do my homework and there are many ways to make a solar cooker, from those with one solar panel to funnel types to aluminum covered umbrellas and even old satellite dishes. Everyone seemed to have their own way of doing it, so I decided to combine a number of methods.
The single panel system didn’t appeal because it looked as if it would involve moving the oven around to catch the sun so I opted for the funnel method, which meant placing panels all around.
I have to say I got lucky with the size of the cardboard boxes. The smaller one was just the right size for the casserole dish and the bigger one, was large enough to cut down to the size needed to accommodate the smaller one.
Work on the solar cooker began at 9pm. I was worried about messing it up because I am notorious for having bright ideas that don’t come to fruition because I’m too lazy and impatient to do things like measuring.
It’s a bit like baking cakes as opposed to cooking. Baking requires exact measurements and care, whereas with cooking you can just throw stuff in a pot and be pleasantly surprised at what emerges.
And that’s exactly what happened. It was definitely a ‘pot luck’ solar oven that emerged.
When I started, I banished myself to the yard because it was a bit cooler so the heavy cutting and sticking was done there.
It took around three hours to cut, secure and line the boxes, and to make the glass cover from a large picture frame.
Then I moved inside to make the panels and secure the foil wrappings. It was already nearly 1am and with an estimated two more hours of work ahead, I had to send someone out for beers.
The trickiest part was where to place the solar panels. They could be attached to the box or to the cover. I decided on the latter although lifting it off would be slightly more awkward in the end but it would not be heavy at least.
Two hours later the ‘oven’ was finished, and so were the beers.
Now it was just a matter of waiting for the sun to come out. Unsurprisingly, the next morning there wasn’t a cloud in the sky as I placed the chicken and pasta into the casserole with some water and seasoning.
I wasn’t able to fit the entire dish, which must be black, into a roasting bag so I just stuck the bottom part of the dish in the bag and the casserole cover sealed it nicely.
Apparently the best time to “put on the food” is between 11.30am and noon and cooking times vary depending on the heat of the sun and the type of food being cooked.
I placed the cooker on a small table in the middle of the yard and thanks to the all-round panels, it was not necessary to move it around at all.
Part of me never really expected it to work. I had visions of a lukewarm mess inside the dish and I kept feeling the glass – wear sunglasses when you do this – to see how hot it was but I had no way to check how it was progressing inside because if I removed the lid all of the built up heat in the ‘oven’ would escape.
Some people place a thermometer inside so they can check the temperature but I was not that organised.
After two and a half hours, I was informed by an offspring that they could smell the cooking food, but I left it there another 90 minutes just to be sure.
The great moment arrived. The lid lifted easily and it wasn’t hot but oven gloves were needed to remove the dish. The chicken was nicely done but the pasta was definitely overcooked and there were a couple of complaints about that.
The dog didn’t complain though. Bless him.
To Construct
Step 1 Find two cardboard boxes one which fits inside the other, allowing around one inch of space all around. Make sure the smaller of the two is big enough to hold a baking tray or casserole dish
Step 2 Make a cover, with glass the same size as the outer box. Clear plastic such as a roasting bag would also do as well as glass.
Step 3 Attach the glass to a cardboard frame.
Step 4 Crumple up some newspaper on the bottom of the bigger box and sit the smaller box on top, ensuring the flaps on the smaller box protrude enough to wrap them over the sides of the bigger box
Step 5 Fill in the one-inch gap between the two boxes with more crumpled newspaper, which forms the insulation
Step 6 Fold over the flaps of the inside box and secure on the outside box.. You now have what looks like a single sturdy box. This is the ‘oven’. Check that the glass cover fits snugly.
Step 7 Line the inside of the ‘oven’ with ‘heavy duty’ tinfoil, which doesn’t tear easily (Available at Debenhams). Try not to have any sticky tape or glue on the inside to avoid toxic fumes when cooking
Step 8 Place either black paper or a black cloth on the bottom of the ‘oven’ to attract heat
Step 9 Start making the solar panels by taping cardboard pieces all around the sides of the framed glass – not to the box itself. There will be gaps in the flaps so tape strips of cardboard along the top edge and fill in the holes with either more cardboard or strong paper such as a magazine cover.
Step 10 Cover the panels with tinfoil and secure at the back. The foil can also be stuck on to the top of the glass with clear tape
Your solar cooker is now ready
To Use
1, Place the food inside the casserole with some water as if you were using a normal oven. The casserole or pot must be black to attract and retain the heat
2. For extra heat retention place the bottom of the casserole inside a plastic roasting bag and then place the cover on top, which secures the bag
3. Place in the sun. Don’t open the oven while cooking because the heat will escape and take ages to build up again.
4. Make sure you place oven in an area with constant sun.
5. Best time to start cooking is between 11am and 12 noon and the food, depending on what you cook, should be ready in two to three hours.
