Introduction: Best Solar Oven

Picture of Best Solar Oven

In my Engineering class, my teacher told us that we had to invent or modify something and post it on the Instructables web site. I looked at three or four solar oven, and using their findings and ideas, I built the Ultimate SOLAR OVEN!  

This Solar Oven is very cheap and easy to make.  It uses around-the-house items that you use every day.  

I hope you enjoy my solar oven.

Ben G.
 

Step 1: What You Need!

Picture of What You Need!

Like I said, almost all the items are things you find around you house.  You will need...

-1 big box (You probably want it to be a square box that is bigger than 2 feet long)
-1 small box  (It should also be square and 4-6 inches smaller than the big box)
-Styrofoam insulation (you can cut it up to fit in the big box)
-Tinfiol
-Black spray paint
-Newspaper
-Glass (One person used glass from a broken scanner.  It will need to be big enough to cover the box.  You can also buy a sheet of glass and use a glass cutter to cut it so it has the right dimensions.) 
-Tape or glue
-Glass cleaner
-Pare towel
-Sharpe (who says it can't be pretty)
-Thermometer
-Baking rack (optional)
-Timer (optional)
-If it isn't sunny, you can try a very bright light.  It probably won't work as well.

Once you have gathered all the materials, you may go on to the next step...
 

Step 2: Paint and Dry

Picture of Paint and Dry

First, you must go out side with your small box and paint the bottom of the box black with your spray paint.  DO NOT breath in the fumes!  Depending on you paint bottle, it should dry in 15 minutes.

Step 3: Tinfiol in the Small Box

Picture of Tinfiol in the Small Box

After the small box is dry, bring it back inside.  Then use the tinfoil to cover the 4 sides.  It should look like the picture below.  You must use the shiny side of the tinfoil.  Also, it is better if you use see-through tape.

Step 4: Insulation

Picture of Insulation

While the spray paint dry's, you can work on the main part of the oven.  The insulation is what keeps the oven warm and that is what cooks the food.  Because the insulation is sooo important, I used two different kinds of insulation. 

The first kind was the syrofoam insulation.  I used half inch white stryfoam plate.  I then cut them down to the length of you box.  I should surround all 5 sides with no cracks.  It is okay if there are cracks, but try to make sure there aren't any.

The second kind of insulation is newspaper.  Place the small box in the bigger box.  If the dimensions are good, there should be 1-2 inches on all sides of the boxes.  Crumble the used pieces of newspaper and stuff them in the area.  Make sure there are gaps between the newspaper.  Those gaps will store the warm heat in the air pockets, which will make the oven warmer. 

Step 5: Reflectors

Picture of Reflectors

By now, the oven sould be almost be complete.

The next step is to make the reflectors.  One person said that unless you live near the equator, you must need these, or the solar oven wont work.  Hopefully, you kept the tops of the boxes that fold over the top to close the box.  You will then cover them with tinfoil.  It is best to be kept at a 45* angle, although if anyone has any thoughts on how to keep it up, please tell me.

Remember to use the shiny side of the tinfoil, and the see-through tape. 

Step 6: Glass

Picture of Glass

The last main step of my awesome solar oven is the glass part.  The more exact it is, the less hot air will escape, which will let your food product to cook faster and better. 

I used a big picture frame, and cut it down to its apropiate shape (My dad helped me with the sharp parts). 

I am not going to tell you how to cut glass, so that will be part of your job to figure out how to cut it.  It will probably tell you on the glass cutter, though.

Step 7: Clean and Protect

Picture of Clean and Protect

After you carefully cut the glass to your desired dimensions, you must make sure it is safe.

The way I did this was I put Super Duty Duct Tape on all the edges.  I also put two layers on the corners there are no injury's.

After, I used glass cleaner on both sides to clean it so it is shiny.  I recomend not spraying the cleaner near the tape; just incase the tape gets soggy and comes off.

Step 8: Rack's

Picture of Rack's

Before you place the glass on your oven, you might want to do this...

An optional idea is that you can place a baking rack on the bottom of the oven.  It would be better if all the sides cooked (top, bottom, and inside).

Step 9: Thermometor

Picture of Thermometor

Another good idea is to use a thermometer.  Depending on the kind you own, you can just place it in the oven and check on after a while. 

My last suggestion to have a timer, and double the timing on your timer for a regular oven.

Step 10: Please Enjoy

Picture of Please Enjoy

I hope you can cook some very edible meals in my oven.  If you have an suggestions or ideas, PLEASE TELL ME!  I also want to hear what your findings were to.  If you have any questions, you can also ask me.

Ben G.

Comments

JoeG17 (author)2017-06-03

A small tip. To remove the sharp edges of the glass use fine sandpaper.

Second prob: Can't boil water at 100 deg C then how can bake things at 180 or more???

ClefairyT (author)JoeG172017-09-01

For your second problem, you're asking how things can bake at above 180°C if water boils at 100°C, right? Well... I mean, water boiling is not really a problem. It's not like all the water will instantly evaporate the moment the temperature hits 100°C, so it doesn't really matter.

ladybugrules (author)2017-08-26

If you want a nontoxic insulation,use cotton or wool batting.I like the idea of using a black cotton tee shirt like one person commented.I will be using an emergency Mylar blanket instead of tinfoil,they are great fro holding in heat

Ev (author)2010-09-22

Doesn't make sense to paint it black then cover with aluminum foil. I say skip the painting step. You DO want to put black cooking pots in it to convert the light energy into heat. Solar cooking recipes even say you can bake a potato by putting it in a black cotton sock!

ChuckMeIntoHell (author)Ev2014-08-01

It may not seem to make sense when you first think about it because visible light can't pass through aluminum, but keep in mind it's not the visible light that's cooking the food, but the infrared light, what we commonly refer to as heat. Aluminum is a good conductor of heat, and hence the heat travels to the other side of the aluminum and is absorbed by the black surface. Black surfaces absorb both visible and infrared light. The heat absorbed will slowly radiate back out, increasing the temperature in the oven. You can set up an experiment to test this out, by making two ovens, one with black material under the foil, one without, and checking the temperature of both to see the difference.

Infrared radiation does carry energy, you're right, but it's not the only one. Actually all radiations carry energy: visible, infrared, ultraviolet, X-rays, etc. Visible light having a shorter wavelength than infrared, they carry more energy than the later. Regarding the properties of aluminum, it does reflect infrared light, almost as well as visible light (I have read about a reflection coefficient of 95% on the internet).

Anyway, the heat absorbed by the aluminum coating is not really of matter. The working principle of solar ovens is to reflect (concentrate) sun beams into one point, not to absorb heat and then conduct it. To come back to the original comment: I also believe painting the inside of the box in black is useless, and if it has en effect of the heat received in the focal of the parabola it will account for less than 1%.

nataliejewell290 (author)Ev2016-05-19

If you paint it black it traps more heat in just fyi and I knew that

RickZ1 (author)Ev2015-06-15

You paint the bottom black to absorb the heat, you don`t put the tin foil on the bottom just the four sides like it says!

pennerwolff (author)2017-05-30

the best

MichaelM745 (author)2016-05-22

What was the point of painting the bottom black if you were going to put tin foil over it. I donut understand

jstoss (author)MichaelM7452017-05-02

lol

JFirsoff (author)MichaelM7452017-01-16

Mmm. Donuts.

You only cover the sides with aluminum foil, so the bottom stays black to absorb heat.

azure639 (author)MichaelM7452016-07-26

Wasted step.

JCookie20001 (author)2016-11-09

Going to make this for my Science class!

RuthC14 (author)2015-11-05

WHAT is the use of glass?

azure639 (author)RuthC142016-07-26

Trap's hot air. You need a good seal around the glass.

MotomiyaN (author)azure6392016-09-10

Where do I put the glass

IsabelK5 (author)2016-05-25

Does anyone know this model is safe to boil water in?

azure639 (author)IsabelK52016-07-26

Water won't boil in it, but after a few hours on a sunny day you can get it up to pasteurization temperature at least (165F).

brad ley (author)2016-06-26

I don't want to be a spoiler here but you might consider a few changes to you oven design. First and foremost, never use any kind of foam, Styrofoam, spray in foam or the like in the solar oven. The foam, as it heats up, will out gas and fill your cooking chamber with poisonous gases. Second, you will want to use watered down white glue or homemade wheat paste glue for the foil. The scotch tape will quickly deteriorate in the heat and will release. If you do not wish to use glass, you can use oven bags. The kind you use for roasting turkeys work very well.

Owenisthebest (author)2016-06-15

Thx Ben it was very helpful

you could also probably use saran wrap in place of the galss but im not sure

I think that the Saran wrap will just melt. You have to use glass or maybe plexi-glass.

no saran wrap isn't enough insulation

KaitlinArmstrong (author)2016-03-30

Hi i'm just wondering if the glass is compulsory or if you can replace it with something else?
Thanks

i went and bought a ginormous picture frame from the dollar store and used the glass from it if that helps

ofiddlestickso (author)2016-05-10

How exactly do you open the oven and put things inside?

Infectednuke (author)2016-05-09

Yeah man i got chu

Infectednuke (author)2016-05-09

Dude ride it out man it's good

I'm freaking out man

Sam_Rosenbaum (author)2016-05-05

Hey man this look awesome is it possible to use pelexise glass instead?

nikkireidenbach (author)2016-04-26

I was wondering if you but the glass just on the small box or the whole thing? I really like the oven though!

herobrine1q (author)2016-04-04

thank you very much.

PahalaW (author)2016-02-25

This was neat thank you. I was thinking of making something at home to help me dehydrate fruit. I think this idea will give me more options. Thanks for the information and good luck to everyone with their ovens.

Blackguyver made it! (author)2015-10-28

Greetings. I work on construction sites, and sandwiches for lunch gets old quick. I NEED this solar oven. Greatly appreciated the instructions, but a finished product photo would've been more helpful than cookies.? Anyway, just made the oven. However, I'm somewhat confused regarding the glass top; should it completely cover both boxes, or simply the smaller inner box?? Here's my finished product:

Anyway, just c

CoryG3 (author)2015-08-31

To keep the flaps up at 45 degree angles, just use a coat hanger and poke holes in each corner of the flaps in the middle and use the right amount of length that will give to the 45 degrees

RickZ1 made it! (author)2015-06-15

I just made this solar oven but I still need to get the glass for the top of it!

fhhuber (author)RickZ12015-08-09

They can work (not as well) without the glass. Its to trap hot air.

fhhuber (author)2015-08-09

Instead of tape 3M77 spray glue on the cardboard and foil. Let the spray dry a few minutes then apply the foil.

Reflector angle depends on angle of the sun and can be used to moderate the heat. Use scrap cardboard an duct tape to make supports for the reflectors.

You NEED the termometer and do not let temp go ever 425. The boxes can spontaneously combust if the oven gets too hot. (You know you made a goodsolar oven when it lights itself on fire...)

You are working with head and flamable materials... have a fire extinguisher or bucket of water handy.

Made camp stove and solar oens for Boy Scouts long ago.

Lee Ann Bledsoe (author)2015-07-25

My kids and are going to spend the month of August without electricity. We made lists of the things we will miss the most: oven was first on my list. Thanks so much! It's fun to make with your kids, safer than an Easy-Bake Oven, and it works!.

SnowB1 (author)2015-06-29

What is the reason of putting a small box into the larger box???

bbjw81 (author)SnowB12015-07-17

Insulation, to increase the temperature by slowing dissipation if heat. "Putting on another blanket" if you will.

Rubeus Hagrid (author)2015-05-10

I really liked your idea I thought you had to have special equipment to make the oven hot anof to make it cook coocies.

CaSe.L.k.PiNk22 (author)2015-03-24

How hot did your oven get? and what is the recipe for the cookies that you made?

lbuchholz (author)2014-08-01

why not try smoothing he edge with a high heat blow torch used in glass blowing.

it softens the edges once it cools so the rough shards are removed. you can tape after for added safety or leave the UN-burry pieces in place. or just re enforce the corners where sharp (if you can find a way to punch a hole in glass, a couple handles may be a nice addition)

Tihomir G (author)2014-05-15

I have an idea to put copper plate painted black on the bottom of the small box. The copper plate will warm up by the sun rays and in contact with the dish where the meal is it will transfer the heat to it. Copper is one of the best thermal conductors.

RadiantLux (author)2010-06-15

Your next step will cover the box with foil. Why do you need to paint it? I would rather not add the toxins to m y oven. Does it make a difference?

Paulus44 (author)RadiantLux2014-05-14

Using black illustration board is better as spray. You also can make a small frame at the bottom and put there small stones or a big tile. Those stones keep the oven longer warm. Make sure the small stones are level. Any way a good presentation.

I live in the Philippines and the angle for the reflectors I use is 67 degrees. I try different angles but 67 work it best.

I also use duck-tape to cover the glass and after more as a years it is still OK. No problem if it is hot.

donhudson (author)RadiantLux2013-08-31

radiant good call. the box doesnt have to be black, my first cardboard cooker i used a black t shirt, ( i too dont like toxins and being a painter i know what nasty things are in them ) you can use reflective material inside, the side effect is that the oven will not get as hot standing alone with no cookware. if however you add a nice piece of black cookware you get good heat. elevate the cookware a bit off the bottom for optimum performance.

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