Solar Cooker Made with a CNC Machine


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Here is a solar cooker that I designed and built. It first started out as a drawing in Google Sketchup. The drawing was then exported to CamBam via my Sketchup to CamBam plugin where G-code was created which allowed my CNC machine to cut out the necessary parts. The design itself is unique in that it is meant to be used with the heliostat projects that I am working on.

Essentially, my heliostat(s) will move to reflect the light towards the solar cooker throughout the day so that the solar cooker doesn’t need to be adjusted as the sun moves across the sky.

That’s the idea anyway. So far, the only thing I’ve done with it is create a lot of heat. I’ve discovered that it takes a bit of practice to get a solar cooker set up so that things will cook. At the time of this writing, my heliostat project has been disassembled so that I can make some upgrades. It will be awhile before I have the chance to try out my solar cooker again, so I figure that I might as well put up what I have so far.

Like I said, this solar cooker was meant to be used with heliostats, so you will probably want to make some changes to the design should you choose to use it as a regular solar cooker.

Solar Cooker Sketchup Model

Here is the Sketchup model of the solar cooker which you can download for free from the 3D warehouse. This should help you see how everything is put together and also help you find the dimensions should you need them.

You will need to have Sketchup on you computer to view the model. Don’t worry if don’t have it though. It can be downloaded and installed for free. Do a quick Google search to find it.

Solar Cooker CamBam Files

Here are the CamBam files for the solar cooker which you can use for generating the G-code for a CNC machine. solarcooker.zip

You will need to cut out:

2 of part 1
2 of part 2
4 of part 3 (I actually cut these out with a circular saw, not a CNC.)
1 of part 4

Putting it together

Here is all of the parts laid out after being cut out with my CNC. The type of material that I used was Lauan plywood which is 2’x4′. Also, it is 5.2mm thick. The measurements on the label for the plywood are an odd mixture of inch and metric which is kind of odd.

Solar Cooker Parts

Here are most of the parts after being put together.

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Here you can see that I added wire across the solar cooker to help hold it together. This was done both on the top and the bottom. It works well enough, but this is something that I should have done on the inside of the solar cooker so that it would look a little better.

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Here are the reflector parts of the solar cooker after gluing on reflective Mylar. I have found that the easiest way to glue the Mylar to the wood is with the type of glue that you spray on. I guess that you could use aluminum foil as well, but I had the Mylar on hand, so I used that. Also, sorry that the picture is dark. I did this part late in the evening.

Solar Cooker Reflectors

Although the reflector parts are included with the CamBam files, I didn’t cut them out with my CNC. Instead, I simply did them with a circular saw. You can see the dimensions in the picture below. Make one, and then use it as the pattern for the other three.

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Here is a sheet of metal after being cut to the correct shape which will later be folded to form a box. Well, almost the correct shape. I accidently made the flaps too big and had to re-cut them a couple of inches shorter. The picture of the Sketchup model below this one gives the correct dimensions.

The metal is aluminum and was originally used as the exterior of an old trailer. It was cut with a pair of snips.

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Solar Cooker Dimensions

This picture shows the sheet of metal after it was folded to form a box. All weather foil tape was used to hold it together, both on the outside and the inside.

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The inside of the box was then painted black to more efficiently turn the sunlight into heat. High temperature paint would probably be best here, but I just used what I had on hand.

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After painting the inside of the aluminum box, I first put a couple of inches of fiberglass insulation at the back of the solar cooker and then placed the aluminum box on top of it. I then stuffed insulation around the sides of the box like you see in the picture below.

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Here you can see the solar cooker with the reflectors installed. The reflectors were first taped to each other with the same all weather foil tape used earlier and then they were taped to the aluminum box like you see in the picture below.

Solar Cooker

Pictures of the Solar Cooker in Action (Sort of)

I seem to have misplaced the pictures I took when testing out the solar cooker after it was completely finished. The picture below shows it before the insulation and aluminum box were placed inside. I’ll take more pictures once I get the chance, but, for the moment at least, we’ll have to wait until I have the time.

In this picture, I have three mirrors reflecting sunlight into the solar cooker. I can’t remember exactly, but I think the max temperature I measured with my IR thermometer at this stage was around 160 degrees Fahrenheit.

Finished Solar Cooker

[bad]

With the insulation and aluminum box installed though, I have measured temperatures around 225 degrees Fahrenheit. This was without any sort of glass or similar materials installed in the front of the solar cooker to help hold in the heat. I’ve since bought some high temperature oven bags to see if they will work. They will hopefully be easier to implement than glass which would be hard to cut to size.

I also need to see if I can find a better pot/container to cook the food in. The one I have has a handle which sticks out and is in the way. I think a container that isn’t very wide should work well. Something like a bread pan maybe.

In the future, I plan on making it so that the solar cooker isn’t quite so deep on the inside. This will decrease the inside volume while also, hopefully, simultaneously increasing the cooking temperature.

I’ll have to experiment to see what works best once I have the chance. Thanks for looking!

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