Instructables
Picture of SOLAR OVEN
SOLAR OVEN that is quick, easy and FREE!!!

I am a packrat at heart and I am always looking at ways to make things from stuff and junk I have accumulated. I have been interested in trying to make a solar oven for a while.
We got a shipment in today that had perishable items and the box was lined with 1 think Styrofoam sheets. When I opened one of the box I realized that I was already on the way to making a solar oven. This is a very easy construct and with junk on hand the cost is ZERO. If you collect junk like I do you should be able to build this solar oven in less than an hour and still come up with good results.
 
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Step 1: Parts and Tools

PARTS:

1 insulated cardboard box (BOX A)
1 cardboard box (small enough to fit inside first box snuggly) (BOX B)
1 cardboard box/cap to fit over BOX A (BOX C)
1 piece of glass – this came from a free scanner that was obtained for free off of craigslist.
Tape (shipping or duct tape)
Black spray paint
Clear plastic bag (zipper bag or twist tie)
Black or dark pot (small enough to fit within BOX B.)

TOOLS:

Craft knife
Ruler (optional)
Cutting board (optional)
Pencil, pen or marker

Step 2: Your first cuts

Picture of Your first cuts
BOX A top removed.jpg
BOX B first cuts.jpg
BOX B cut down to size.jpg
I resealed the box with tape and then sliced one side off with my craft knife (BOX A). Once I had the side removed I was able to see how large the second box needed to be. I found a box that would fit fine from side to side but it was a little to long. After a little cardboard surgery I was left with a modified box (BOX B).

Remember that anytime you use a knife or other sharp tool to practice responsible use... safety first!

Step 3: Paint it and stick it...

Picture of Paint it and stick it...
BOX B inside BOX A.jpg
wall construction.jpg
I spay painted the inside of BOX B to help capture the heat from the sun. Slide BOX B inside of BOX A and there should be a tight fit and you end up with a cardboard/Styrofoam/cardboard wall construction.
SparkySolar2 months ago
Here the sun is not very bright
I have been unable to fully test it
but it made bees wax from rock solid uncuttable to soft pliable putty
SparkySolar made it!2 months ago

i upgraded to a cooler, as this is what I had in my house

image.jpgimage.jpgimage.jpgimage.jpg
sdbigguy (author)  SparkySolar2 months ago
Did you mean that you upgraded an old igloo cooler into a solar oven? I would be interested in what kind of results you got. Thats for viewing my instructable. I made this solar oven a long time ago and no longer have it.
Yes
I took the lid up cut iut a section of the 2 layers of plastic. I made sure to leave T least 1/4 inch lip to rest the acrylic plastic on.
Double sided tape holds the glass onto the lip.
Ductape, borrowed from my daughter sealing it from Top.
I hope the pictures help

I had to use what I had at home
Rima
triumphman2 years ago
Doesn't the tape get hot inside the lid and drop the glass ? Tape is not very heat resistant. I would not rely on the glue to hold up very long. Just an observation. Thanks for the instructable. I am working on a pocket size one right now. There is a lot of variables I have to consider. Many ideas to research too. Everyone has a better way. Maybe a future 'ible .
ckaur3 years ago
can we use can instead of black pot
sdbigguy (author)  ckaur3 years ago
I used a can that was painted black. I am told that if you use something like a cast iron pot or skillet that it give a more even cooking effect because of the retained heat. I haven't tried that though.
ckaur3 years ago
can we use any transparent glass ot its urgent to use scanner glass only...???
sdbigguy (author)  ckaur3 years ago
You can use any glass. I used the scanner glass because it was what I had and I felt confident that it would not easier break.
ckaur3 years ago
are these bricks...?
sdbigguy (author)  ckaur3 years ago
That is just my patio that shows through the glass. If I photoshop'd them out you would have missed the glass.

I think someone should post an instructable on different solar recipes, like the one tecneeq suggested.

By the way, if someone can prove to me that a solar oven can bake a cake, then it's going straight to the top of my list of things to build.

I like cake...

you can def cook cake bread etc using solar one reference is the book sunshine to dollars. the writer shows a lot of things that can be done with solar, and gives results! I will post an instructable about these things soon, you can use box mix just give it enough time and heat
you could but it wouldn't brown. Solar cookers are the same as slow cookers.
sharlston5 years ago
burning syrofoam releases toxic gasses you know
sdbigguy (author)  sharlston5 years ago
I will agree with you that burning styrofoam does give off toxic gases but I don't have anything in this INSTRUCTABLES about burning styrofoam. Thank you for viewing my INSTRUCTABLES.
oh sorry i misread it whats with the INTRUCTABLES?
sdbigguy (author) 5 years ago
I have actually tried one of those full page magnifying sheets, The focal length is usually very specific as to where the focus is. You also have to be careful that you don't focus on the wrong surface because you may just end up with a fire trap instead of a solar oven.

As and aside. for people that want to play with fresnel lenses on a large scale try going thru craiglist or your local freecycle webgroups. Look for large projection screen TVs. The screen cover is one of these lenses. CAUTION... when playing or using one of these lenses be sure to use EYE PROTECTION (welding googles are great), and keep an eye on flammable items in your "WORK AREA". You can use this to burn wood, boil water and with the right set up you can cook things but it is VERY HOT, not the thing I would use to bake bread. AGAIN... in big bold letters CAUTION
larze_fat5 years ago
I got a question about making the inside even hotter by using those full page magnifying glasses
lilykoart5 years ago
wayyyyy back when i was a wee one, i remembered discussing making a pizza box oven in 3rd or 4th grade. i had always wondered why it wasn't more popular cause it sounded cool, like an easy bake oven (which my mom wouldn't allow thinking i'd burn down the house)
lilykoart5 years ago
way cool & clever idea! at first i thought bricks were needed but i figured out the pix. wonder if you can bake a cake??? gotta try this, i like it cause there's no wiring. thanks for the instructables!
PS1185 years ago
I hope you won't be offended, but I'd like to offer a couple of design improvements. 1) A fresnel lens. They usually have ones at RV stores or Auto stores that stick right on a piece of glass. Also they are sold as "sheet magnifiers" for people with poor eyesight. 2) Cardboard is flammable. You might consider a different building material, especially if the plan is to leave this unattended for hours on end. ;)
tecneeq PS1185 years ago
I agree with sdbigguy on this. I wouldn't use a lens nor care about the cardboard. Why did you spraypaint the inside cardbox black? What you want is as much light as possible on the cooking pot. I would use aluminum foil glued to the inner box to reflect as much light and thermal radiation away from the cardboard. The only thing absorbing light and infrared should be the cooking pot. To cook your stuff even faster you could use some cardboard sheets, glue aluminum foil to it, and use them as reflectors to get more light into your box. It made a big difference for me. The problem with the plastic bags i found is that it's just annoying. I use a bunch of big mason jars (i'm not sure it's the right word, a glass jar that is closed with a glass lid using a rubber seal), it's spraypainted black and it's used as it is. No need for a plastic bag. Classic solar recipe: one jar for rice, one for lentils, one smaller jar for a few eggs. I like to add lots of curry and some pineapple to the rice. The lentils can be spiced up with a pinch of salt and a teaspoon of vinegar. I add raw veggies after cooking, sometimes also fruit. It's a nutrient rich meal for few cents that is easy to prep. You can't overcook or burn it. And the energy used to cook it is free, wich makes sense in a country where you pay 24 euro cents per kW/h :).
sdbigguy (author)  PS1185 years ago
Thanks for the comment. I have a giant Fresnel lens that I got out of an old TV (also gotten for free on Craigslist) and I rarely take it into the sun because I am afraid of burning everything down. It will bring wood to open flames in seconds. I would be worried that I would burn anything I was trying to cook.

As far as the cardboard question... “If you build a box cooker out of cardboard, won't it catch fire?

No. Paper burns at 451° F (233° C) and your cooker won't get that hot.”

I got this fact from Solarcooking.org FAQ page.

Have a great day and remember... REDUCE, REUSE and RECYCLE!