Guess I'll have to try solar cooking again. Not too soon. I've still got two feet or more of snow.   I really liked an article where a school made solar ovens out of pizza boxes and if I'm remembering right they even cooked mini pizza :)  My last solar oven got destroyed in a wind storm and never replaced it.  Wouldn't have wanted to move it any how.  Easier to just make another.  We did set our in a wheel barrow once.  

I made two versions of the "minimum" solar box cooker (cardboard, foil, oven cooking bag), one large and one small.  The larger one works much better, perhaps because it captures more sun, perhaps because the space between the inner and outer boxes is greater (so better insulated).  My only tweak to the design was to rig up a sturdier propping mechanism for the reflector panel (after I had a wire prop punch through my oven cooking bag window a couple times on breezy days).

 

At my latitude (38), I've had success with using my larger box cooker March-October.  I've measured temps up to about 280 F.  My main use for the box cooker is cooking dry beans (soaked overnight in the fridge).  A retained-heat ("haybox" type) cooker makes a good backup for when the weather doesn't cooperate.  Unfortunately, the retained-heat cooker is so convenient that I've gotten out of the habit of using my solar box cooker, but maybe I'll get back to it this season.

Thanks for the info QMacrocarpa.  My inner box measures 14" x 17" and fits my black speckled metal roaster.  However, I found the outer box in the basement is a little too small.  What were the dimensions of your larger Minimum Solar Box cooker (both boxes)?  And what is a retained-heat ("haybox" type) of cooker??

P.S. I am at latitude 41.

 

CharlieB:

Thanks for the info QMacrocarpa.  My inner box measures 14" x 17" and fits my black speckled metal roaster.  However, I found the outer box in the basement is a little too small.  What were the dimensions of your larger Minimum Solar Box cooker (both boxes)?  And what is a retained-heat ("haybox" type) of cooker??

Here are the dimensions of my more-successful (larger) box cooker: 

Outer box: 30.5" x 29" x 10" tall.

Inner box: 27" x 20.5" x 7.75" tall.

Reflecting panel: 27" wide x 20.5" tall (matches inner box dimensions).

A smaller box cooker would probably work better with a supplemental reflecting panel for more sunlight capture, but I haven't come up with a clever way to add one.

With retained heat cooking (there are a lot of other websites on it, try Googling "haybox cooker") you heat up the stuff you're cooking and then move it to an insulated container which will keep the pot hot enough that the contents will continue to cook without additional application of heat (or you might need to reheat once part-way through the cooking time).  I mostly use it to cook (soaked) beans.  I usually start with 2 cups of dry beans.  I find it really handy because not only does it reduce fuel use, it's just much less of a hassle not to have to hover around a pot of beans threatening to boil over all the time, so I cook beans much more now than I used to.  My "haybox" is actually a heavily insulated cooler with a ceramic trivet set in the bottom to put the pot on, and a big acrylic scarf to wrap around the pot to keep it cozier.

Thanks again QMacrocarpa!  I really want to try making a solar cooker.  Since you had better luck with the bigger boxes, I'll go with your dimensions.  The haybox cooker is a good idea too (checked out the link and info).

We've been showing women in Kenya how to make the solar funnel cooker developed by Steven Jones. We have a very detailed description, with photos (and also in Swahili, if anyone's interested) on our family website: www.bradishkenya.com. If anyone uses it I'd really appreciate your comments.

I checked out the site but not due to the cooker (I have a strong feeling for Kenya; been there on safari and was married to a Kisii). The pictures of the kids are melting my heart! 

Hello, I'm new here so I don't know how frugal is frugal but here is a cooker that is different, it is only 97.00 but it could be duplicated I'm sure.

http://www.wsetech.com/solarcooker.php

Lois

A man in our community showed me some that he is working on.  Here are some of his clever ideas:  For the outside box, use a plastic insulated cooler.  Between the inner and outer box, layers of cardboard provide insulation.  The inner box is lined with foil.  He uses glass canning jars to cook with, or lightweight black pans.  The canning jars are painted black on the outside to help collect heat.  For glass, he uses flat auto glass, just sets it on top of the inner box.  You can put an adjustable vanity mirror on the lid, to reflect more light into the box.  You can also make wedges for adjusting the angle of the whole outer box to squarely face the sun. 

 I got a free cooler out of our neighbor's free pile the other day and can't wait to try making one with the kids.  At one time I was going to make one from a plan in a book, but why make a heavy wooden box when all these lightweight materials are free?