Hello Everyone,

Thanks for checking out this Instructable.

First I need to give credit where credit is due. I might add this cooker design is by no means my invention and is not a new theory.
Professor Steven E Jones of BYU I think originally designed and tested the model. Follow the link to his page and read how he did it.

I decided to post my version and my results here as, just one more way to work with this existing design.

Okay let's get started!

First off hunt for a cardboard box  anywhere from aprox 30" tall with bottom and top unassembled.
You will be looking for aprox a 2:1 ratio in size. I.E. 60" wide by 30" tall, twice as wide as tall if that helps.

I happened to have some black duct tape on hand so that ended up being what I used. It has no significant purpose other than it was available.

I also had one piece of vertical blind that had broken off at the top, so I decided to recycle it by using it as support members along fold lines. This is not really needed but I like a good durable unit when I finish a project. ( I PLAN ON USING IT)!

Next I taped all the box corner/fold seams both front and back. This gives a nice surface to work with. Let me make a note here****
USE THE 2:1 ratio for size. If  you box is other than that cut it to fit aproximately . It doesen't have to be perfect. An inch or two longer would be better than shorter of course.

I used a box that was too long and you will see later where I just folded one side back and used it for added strength. You can do this if you wish but trust me depending on the thickness of your cardboard you could be having to work to hard to keep the shape you want in the finished product.

You will notice is taped the support pieces to the cardboard box. DO NOT TAPE THEM OVER A BOX JOINT **** if you do folding up and storing it later on will be very hard to do. I taped them on next to the folds and often over lapped the tape with the tape at the joint itself.

Step 1: Time for Shaping and Gluing

As you can see in the first picture the box when too long stretches out quite aways.

Next I cut the 7" radius out of the center of one panel (sorry no picture) but you can see it on the link in the first step or in the photo where I am attaching mylar around it.

After cutting the radius I folded the box to create the aprox 60 Degree angle of folds. Picture the center at 90 degrees to the long side in the top center of the  radial cut. then fold 30 degree bends to the right and left respectively to get your funnel shape.  30 + 30 is 60.

Another way to say it is you have folds that look like sunbeams coming from the cut out does that help?

After getting my folds right and of course my plastic blind sections to bend  :)  then I applied gorrilla glue to all the fold lines and a few other areas along edges etc.   I then spread out the mylar on the floor and with the assistance of my partner we turned the cardboard over and laid it in the middle of the mylar sheet. we then piled on the books to help the glue fully connect with both the mylar and cardboard.

You may not need this step... but then it was time to go get some dinner :)   After an hour or so I came home and removed books and finished wrapping and taping the mylar to the back side. (notice I didn't say glue)  with the tape if you need some flex room you can lift and retape etc.

as you fold over the mylar on the back you will also have to make a way for the mylar at the cut out to be secure.  I used clear packing tape on the front around the cut out to make sure it was stable and would not ripe unexpectedly.

Wrinkles are a bad thing for a solar cooker. Maybe you could find a material better than cardboard to make the funnel.<br> <br> Aluminized plastic sheets (<a href="http://www.google.com.ar/imgres?hl=es&client=firefox-a&rls=org.mozilla:es-ES:official&noj=1&tbm=isch&tbnid=gbhP8S9DEWPxaM:&imgrefurl=http://spanish.alibaba.com/product-gs/pet-reflective-film-aluminized-mylar-on-led-and-solar-product-535536274.html&docid=_bRtFzc8o68FMM&itg=1&imgurl=http://img.alibaba.com/photo/535536274/PET_reflective_film_aluminized_mylar_on_LED_and_solar_product.jpg&w=567&h=567&ei=F9hPUKSRG4Xc9ASI7YGIDw&zoom=1&iact=hc&vpx=492&vpy=291&dur=7888&hovh=225&hovw=225&tx=117&ty=116&sig=111307796361559523119&page=1&tbnh=148&tbnw=148&start=0&ndsp=19&ved=1t:429,r:8,s:0,i:95&biw=1366&bih=655" rel="nofollow">PET</a>, <a href="http://www.google.com.ar/imgres?hl=es&client=firefox-a&sa=X&rls=org.mozilla:es-ES:official&noj=1&tbm=isch&prmd=imvns&tbnid=1JdMBUf8XMWCqM:&imgrefurl=http://lacasadelceluloide.wordpress.com/2009/05/17/poliester-metalizado-2/&docid=HHwQBbXrf73HLM&imgurl=http://lacasadelceluloide.files.wordpress.com/2009/05/dsc042605b50255d1.jpg&w=1152&h=864&ei=hdZPUMu4NoKMrgH9toHQBA&zoom=1&iact=hc&vpx=386&vpy=159&dur=151&hovh=194&hovw=259&tx=127&ty=99&sig=111307796361559523119&page=1&tbnh=153&tbnw=204&start=0&ndsp=18&ved=1t:429,r:1,s:0,i:73&biw=1366&bih=655" rel="nofollow">polyester</a>, <a href="http://www.google.com.ar/imgres?hl=es&client=firefox-a&rls=org.mozilla:es-ES:official&noj=1&tbm=isch&tbnid=GrTWemTep9YOxM:&imgrefurl=http://spanish.alibaba.com/product-gs/aluminized-mylar-370413038.html&docid=tz7VQ27rHtwTSM&itg=1&imgurl=http://img.alibaba.com/photo/370413038/aluminized_mylar.jpg&w=284&h=284&ei=nthPUOanPIXO9QTI3IHYDQ&zoom=1&iact=hc&vpx=1101&vpy=29&dur=4696&hovh=224&hovw=224&tx=107&ty=147&sig=111307796361559523119&page=2&tbnh=140&tbnw=140&start=18&ndsp=24&ved=1t:429,r:5,s:18,i:144&biw=1366&bih=655" rel="nofollow">mylar</a>, etc) 0.1 mm or more are good enough to do it. They are not too expensive. Choose those less translucid and more bright.<br> <br> Anyway, good project.

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Bio: IF YOU ARE IN THE GREATER Colorado Springs AREA AND WANT A NERD PROJECT FRIEND/BUDDY HIT ME UP. I enjoy building projects, coming up ... More »
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