How To Make The Best DIY Solar Oven For Under $50 Bucks
by Guerrilla Homesteader
Have you ever wondered how you would cook food or boil water if the power went out? How about if firewood was unavailable? I’m guessing the answer is yes since you’re reading this right now. A great solution is a DIY solar oven. At least it is during mostly sunny days of course.
A solar oven is a device that reflects and focuses the sun’s solar energy into the oven box to heat food or even boil water, if you need to. Solar ovens are a great way to cook food without using propane, natural gas, or electricity!
They are also not too difficult to make if you have some tools and some scrap wood laying around.
In this step-by-step guide I will show you how to make your own solar oven. It is NOT made from a pizza box like some articles describe. The design in this article is superior to many other DIY solar oven designs I’ve seen and it does a kick butt job if I do say so myself.
There are some very nice pre-made solar ovens for sale on various websites if you’re willing to spend $300 to $500 for them.
Official All American Sun Oven is an example of a nice one in my opinion. I haven’t personally tried it though. I did base my reflector angles from that design and they work well.
Supplies You’ll Need For Your DIY Solar Oven Build
- Some scrap plywood(amount varies by how big you want make it)
- Small wood screws or small nails
- One roll of reflective HVAC aluminum foil duct tape
- Heavy duty Velcro or Alfa-Lok fastener strips
- A piece of clear acrylic or plexiglass sheet for the lid that is larger than the finished size of your solar oven box opening
- A small piece of twine or wire for lifting the lid
- Cardboard for the reflector panels
- Scissors or utility knife
- Jig saw with fine tooth blade for cutting the lid
- Circular saw for the wood box
- Battery drill and bit for screw holes (to prevent thin plywood from splitting if you’re not using nails or wood glue)
- Card board boxes cut to make the reflector panels
- Optionally-wood glue if you don’t have nails, screws or drill. Disclaimer: I haven’t tried the glue so use it at your own risk.
- For best results I use a cast iron dutch oven for cooking in it but it’s not a deal breaker. A black pot will be the next best thing.
Note: Using epoxy instead of wood glue might stink up your food and water, fyi. I’d avoid that.
Decide On Your Solar Oven Box Size
The dimensions of the inside of my DIY solar oven box are 16.5 inches wide by 12 inches deep by 9.5 inches tall. This gives me enough room for my dutch oven and for most of what I want to cook in there. Feel free to make it larger or smaller to suit your own needs.
Just remember to take into account the thickness of your plywood if you measure from the outside of your solar oven box because the inside will measure to a smaller size than the outside. I would start by measuring and cutting the floor of your box first and then measure the walls to fit from there.
If you want to fit a standard size cookie sheet inside I would go 3 or 4 inches wider. The cookie sheet I have in there was too long so I had to bend up the ends to get it to fit inside.
The cookie sheet is handy because it catches the occasional spills or boil overs from whatever you’re cooking. It also keeps you from wearing out the reflective tape on the bottom of the box.
How To Make The Cardboard Reflector Panels For Your DIY Solar Oven
Once you have your oven box made to the size of your liking, you’re now ready to make your reflector panels out of cardboard. You can use the cardboard from any cardboard boxes you can find as long as it’s large enough for the sizes of your panels.
Your reflector panel sizes are dependent on the size of your wood box. A picture is provided below that shows the approximate sizes of the panels that I made along with the angles I used. The ‘front’ reflector panel shown below, will sit at a 45 degree angle leaning towards you if you were standing in front of the solar oven.
How To Apply The Reflective Duct Tape To The Box And Panels On Your DIY Solar Oven
You now have your panels cut out to size and shape as well as the oven box assembled. Remove any dirt or dust from the panels and box to ensure the tape sticks well. Get your reflective tape and stick it to the inside of your box until it’s completely covered on the bottom and sides.
Some solar cookers have a black colored surface inside the oven box which probably works well, but I chose to use the reflective tape which works well in my design. I didn’t want to use any kind of paint in my solar oven for health and safety reasons.
I’ve heard of people using black construction paper for this purpose.
Now you will apply your reflective tape to one side of all of your reflector panels. Try not to leave any areas uncovered by the reflective tape so the full power of the sun is reflected and focused to the oven box.
How To Cut The Clear Plexiglass Lid For Your DIY Solar Oven
After you have the wood box sized to your liking and assembled with the wood screws or glue etc., lay your clear lid material on top of the assembled box. Then use a sharpie or other fine tipped marker to trace a line around the box onto the lid as accurately as possible. Then when you cut the lid with your jig saw, you will cut to the inside of your markings.
Try to use a fine toothed jig saw blade as it should reduce cracking and leave a cleaner edge on the lid. A file can be used to smooth out any sharp edges that are left.
That way you should have a lid that is slightly smaller than the box and will fit within your reflector panels after they are velcro’d onto your oven box. If you can’t get your hands on some clear plexiglass you could try using plastic wrap as other people have described.
I’m not sure how plastic wrap will hold up to the high heat generated by the oven that I have made so use caution if you do that.
How To Apply The Velcro To The Box And Reflectors On Your DIY Solar Oven
You’ll need to put your velcro strips on all four sides of the oven box at the top so the reflector panels have something to stick to. I used three strips on each side of the box as you can see below in the photo.
You will need to match up the velcro on your box to velcro on your reflector panels. I would use the velcro to attach your reflector panels to each other as well. This allows you to take down your oven and panels for better storage.
Troubleshooting Your DIY Solar Oven
The following are some variables that affect how your solar oven will work. If you aren’t reaching at least 200 degrees F, see the list below for remedies.
- Is it a sunny day or cloudy
- Is it windy
- Is it hot or cold outside(summer, winter)
- Are the reflector panels made correctly
- Do you have enough time to cook (for a few hours)
- Are you using a thick enough cooking pot (cast iron works well-the heavier the better as it will absorb and hold the heat better)
- Is your solar oven pointed in the right direction
How To Use Your DIY Solar Oven
Time, Temperature And Wind
Your solar oven requires a fairly long time to cook food thoroughly. I would plan on a few hours to be safe. And always use an digital meat thermometer to verify proper cooking temperatures for what ever type of meat you’re cooking.
I can reach anywhere from 200 to 250F in my solar oven and on really hot summer days I will get it up to 300F! As you get used to what it can do and keeping it aimed at the sun, you’ll get the hang of what works and what doesn’t.
I cooked a few chicken legs in my cast iron dutch oven, in my DIY solar oven for roughly three hours and that was enough time in my situation. Less time might have even worked as I was not attending to it too consistently.
I live in Arizona near Phoenix and it was summertime and sunny with 110 degrees F. In cooler climates your cook time will vary from mine.
Wind is another factor that will change things. The reflector panels, as I made them, won’t stand up to too much wind before they blow off. Calm days are best.
Summer, Winter And The Sun’s Position
Winter or summer sun will affect the performance of your DIY solar oven. The sun is higher in the sky in summer than it is in winter. As the sun progresses lower when winter approaches you’ll need to raise the rear of the solar oven to compensate for the lower positioned sun.
Also, as the sun crosses the sky you’ll want to rotate your solar oven to face the sun periodically to maintain the highest heat level. Use an oven thermometer like the one in my pics to monitor the air temperature in the oven. This will help you to position your oven by watching the heat raise or lower.
How To Position Your DIY Solar Oven
I’ve found that if you stand directly behind your oven and aim it straight to the sun, this gives your oven the maximum cooking temperature. Not much tilting is needed, if any in summer because the sun is at it’s highest in the sky.
In winter when the sun is lower, some tilting of the oven toward the sun is needed. Just place a couple rocks or a piece of wood under the rear side of the oven to raise it, to better face the sun. Using an oven thermometer inside the box will quickly tell you how well you’re aiming the oven.
How Outside Air Temperature And Cast Iron Pots Can Increase Performance Of Your DIY Solar Oven
The outside air temperature will affect the heat levels in the oven. This is another good reason to use cast iron cookware in the oven as it has a greater thermal mass and will absorb and hold heat more consistently than thin metal cookware.
The black color of cast iron cookware also increases the solar heat gain inside the oven.
This will help to maintain higher heat levels when passing clouds go by and block the sun for brief periods of time.
To Sum Things Up
In conclusion, a solar oven is a great way to cook without using any fossil fuels. They are easy and fun to make, and they teach about the power of the sun. Solar ovens can be used to cook anything from a simple meal to a gourmet feast. With a little creativity, solar cooking can be a great way to save money and energy.
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