/diy/ - Do It Yourself

>>128095
>heavy aluminum insulated oven box
WUT

You know aluminum is an excellent thermal conductor, right?

Also, is this intended to be portable? If so, why not go with aluminum throughout?

Fixed? Go with steel throughout (mild for frame and box, possibly stainless for reflector. Mild can polish up quite nicely, but would be subject to corrosion from humidity and fingerprints).

I want it to be pretty sturdy but still somewhat portable, might put wheels on 2 legs like a grill. Once it gets where its going its not going to move much but it is going to live outside so it must be able to withstand the elements.

Also, equipment supplied but I will have to purchase my own materials so I'm trying to be price conscious as well. If it turns out nicely I might want to try to sell a couple and would like to be able to make a profit.

>>128095
suggestion: make a foldable frame with a giant fresnel lens, with a also foldable mount for a cast iron frying pan in the focus.

Should be cheaper, lighter and have some portability.

Thought about a lens but I like the traditional design because I want something that's easier to use and doesn't require much maintenance. If it works well It will be a prototype for a friends charity, it has to be user friendly to indigenous Mexicans in the middle of the desert.

google. and stop being a nigger

Protip: aluminum isn't as light as most people think. You end up using thicker material to make up for the lack of strength. Aluminum is also more costly than steel not to mention harder to weld. I would stick with a low thickness steel angle iron frame then weld plates or sheets on the side. You could mount it to a dolly (pic) then weight isn't an isue.

>>128113
>it has to be user friendly to indigenous Mexicans in the middle of the desert.

yes. because until you came along they'd never managed to cook anything. ever.

>>128117
nice tip.

also, aluminium being a wonderful heat conductor will take some of your preciously concentrated energy outside the over.

>>128118
Respiratory diseases caused by a life time of cooking in a little hut over a wood burning fire are a big health concern, also harmful to the environment.
>>128117
>>128119
Thanks for the input, I'll take that into account.

>>128129
>>128129

a few wood fires are not harmful to the environment, natural wildfires have been happening before humans even walked the earth

http://www.alro.com/

Here's the company we order steel though. The have information on weights so you could aproximate the weight of your oven before hand. I'm assuming you're out west so you can't order from them but a quote is always useful. their staff is good and will awnswer any questions you have about their stocked materials. When ordering br sure to ask if they have any drops this way you can avoid a cutting chare. Also it may be cheeper to order a regular stock increment (for alro 20ft) as oppsed to 17ft becuase of a cutting charge. Just an FYI.

copy a sunbox

Your idea screams HEAVY. Solar stills need to be lightweight and portable because, believe it or not, the sun does not stay in one spot for long.

hi. I used to build pizza box solars, but have never built a real one., probably a stupid question, but why not install a hinged fiberglass cover to retain heat?

I've made several types of solar cookers. From super cheap and small to one with lots of R-value.

I've made solar funnels, ovens, parabolics, and panel cookers. I've made around 100 meals thus far, have cooked in 2 feet of snow at 2 degrees Fahrenheit outside temp.

Plans and tons of info,

http://solarcooking.wikia.com/wiki/Solar_Cookers_World_Network_%28Home%29

My recommendations,

-Build as light as possible.
-Box cookers are best for just about everything and every type of cooking.
-More R-value insulation = hotter ambient ait temps for box cookers
-For affixing aluminum foil to wood or cardboard use a mixture of 1 part water and 1 part wood/Elmer's glue. Spread it with your hand, towel off hand, and roll foil over the glue, wait till it dries, and cut off extra.
-Foil works better than glass mirrors because there's no glass for light to go through
-2 glazings (glass, plastic, etc) are best for the window for a box cooker

continued...

pic is my main cooker

>>128295
From my experience,

-Funnel cooker: Novelty really. Lid gets super hot. Does okay cooking food. The funnel isn't all that great for portability and does not store well and has lots of heat loss. I'm sure you could make some sort of folding one. The unit is pretty light. A glass cooking vessel painted black seems to be best.

-Panel cooker: Functional and quick to set up. It takes forever to cook with for small unit, and has lots of heat loss. VERY portable. Very nice for reheating food.

-Parabolic cooker: Best as a stationary non-portable unit. Can take a long time depending on its size. Lots of heat loss and it has a very finite focal point. Left unattended and it could cause a fire if something was in the focal point and flammable. The focal point changes as the sun moves so helio-tracking by hand or electronically is a must.

-Box Oven cooker: Insulation is key, can be made portable, and collapsible. Depending on the design and size it can be easy to store or take up a lot of space. These can be stationary fixtures as well and can be very large and cook massive amounts of food. Smaller reflector space can be used because of its heat retention. I prefer these over the rest. Great for baking, pizza making, etc.

Another pic of the same cooker. This unit, when empty can easily and quickly reach 450F. All foods cook in about 1 hour or less on a sunny day.

>>128267

Strictly speaking, the sun stays in one spot forever.

Materials,

-If your solar box oven is to attain high temperature you should use clear thermally toughened safety glass for the inner glazing. You can usually get by with plate glass for the outer glazing and for low temp cookers.

-Portable units for traveling that may be taking hits, bumps, and jarring (ones for camping for instance) should use safety glass for the glazing(s).

-If you make a solar box oven, I recommend making the reflector panels in the style used by the Heaven's Flame solar cooker. They are easy to make, and can fold up for storage. They also capture a lot of sun at just the right angle.

-For winter use, the sun is low, a gimbled tray inside the cooker will come in very handy. You can also make a unit that is angled to the sun more than it normally would be.

-Tightly packed cardboard is a very good start with insulation. You can use it as the inner insulation shell. Other less heat-tolerant insulations can be used further away from the center of the cooking chamber. For instance, an inch of cardboard, an inch of Celetex(black fiberboard, and two pieces of blueboard foam are what I use on my main box cooker. The foam would melt quickly if it wasn't properly insulated away from the cooking box heat. The sides of that cooker are usually cool while inside temps are 400F+.

>>128303
Nope, not quite.

The sun orbits around the center of our galaxy just like our planet orbit around it and the moon around us.

>>128303
>>128303
>>128303

>sun orbits galaxy
>galaxy is constantly moving too

>>128095
>so much metal

This will weigh a ton, as others have already stated. If you wish, you can us thin sheet metal for the inner cooking chamber of a solar box cooker. The rest of the cooker can literally be all cardboard, even the reflectors. For the reflectors, it is best that they are not a mirror polish. A mirror polish creates a smaller focal point. You need a focal point that hits the entire window of the cooking chamber, not one smaller area of it. This is why simple aluminum foil works best.

There's no real reason to make a metal one unless you are making it to withstand an outside environment 24/7. In which case go for an all metal oven. If it needs to be portable, use a dolly for something that heavy, if it is going to be big unit.

>>128101
This is why I should read ahead when starting to answer questions. lol

>might put wheels on 2 legs like a grill

Great idea. Make sure you put lots of insulation in it and that it can't get wet in rain. A handy tarp and bungie cords is a must. Build a compartment under the cooker to house these things. Then if it rains while the panels are up they won't pool water of you put a tarp over it.

Pic is of my bread riser and my main cooker. Most solar box ovens are low enough temp that you can rise your bread and bake it in same cooker. Mine gets too hot even without the panels attached.

>>128108
A solar furnace is very specific when it comes to alignment. You will also need a massive Fresnel lens. Like one from an old dead Rear-projection TV. Those can be 4 feet wide. This type of solar cooker relies on clear skies at all times and has very high heat loss.

>>128113
Google, "Cookit solar cooker". These are easy to make, light, portable, easy to learn and use, and work very well. There's a massive world wide program to hand these out to peoples such as you listed. They are literally rape prevention (in Africa, no joking) and respiratory disease prevention devices.

>>128138
Smoke is not good inside your lungs.

>>128283
The use of multiple glazings over the main box os common. Normally no more than 2 glazings are use. 3 causes too much blockage and reflection. 1 causes heat loss when wind hits it and causes condensation inside on the glass which also affects heat absorption of the cooking chamber.

>>128303
As the sun moves across the sky it is best to rotate your cooker to directly face it. Panel cookers and especially box ovens need to be realigned far less than a parabolic cooker for instance.

I'll post a few pics of the different solar cookers I've made.

This one is a collapsible solar box oven. I used it for years. I kept it behind the seat of my truck. It was great for heating up road food and for camping and hiking trips.

A dog destroyed it while it was cooking. The dog actually dug under a 6 feet tall fence to get to it. lol It was only a prototype anyway.

Here's a tiny one I made to toast a cheap off-brand pop-tart. I didn't use the glue though, only the tape. The foil is from the tart wrappers, glazing is the plastic bag, box is the tart box, and the black thing is black-painted foil. The towel acts as insulation as does the one in >>128323

I think this took about 30 minutes to cook though it may have been done sooner than that. With 4 reflectors the plastic glazing was starting to melt.

This is a solar funnel cooker. I used coat hanger wire to make the jar hanger and for making a cage so that the plastic shopping bag didn't touch the jar sides. It would have instantly melted if it had. The bag acts as a wind break and slight insulation. This works fairly well but is cumbersome to use because of its shape. I put scotch tape over a section of the jar then painted it and removed the tape so there would be a small viewing port to check if food it baking or boiling. The mason canning jar also acts to pressure cook the food. Don't make any kind of pasta in this as it will pressure cook it to oblivion and be HORRID. This is good for beans if you leave room for the foam.

The collapsible cooker cooking terrible pizza for a terrible but tasty American dinner.

>>128095
OP, this is a 2-second sketch I did some years ago. It was to be a pizza oven that I never got around to making. This uses a non-tinted glass sliding patio door as the glazing (taken out of the frame and put into a less weighty wooden frame). Pitty I never fleshed out the design. I'm only posting it because your description reminded me of it.

Here's plans for a panel cooker like the Cookits.

>>128340

>>128342

>>128343

Plans I made for a solar funnel cooker. I never made plans for the cooking jar or the hangers though. There's a few plans online though.

Also, for your panels of any cooker, using aluminum means it will corrode over time. Making the panels so they can be easily removed, stored, and replaced cheaply.

Thanks for all the input Solar Star it sounds like you have plenty of experience in the area. Your sketch >>128339 looks pretty much like what I had in mind.

>>128390
Glad to have helped.

The best advice is more reflector area the faster your food will cook.

You can also pre-heat an oven by lining it with brick or stone then heating it up for a while before putting your food in. The thermal mass will keep temps even when clouds pass by. When the sun goes away completely you can wrap the unit up and hold all that heat in for longer so it is still cooking your food. Paint the stones/bricks black with oven safe paint.

A black interior oven will raise the ambient air temps inside while a reflective interior oven will reflect some back out and a lot on the food or container you are cooking. Both had advantages. I prefer the black interior so no heat it lost.

Check out this style of box cooker and how you adjust the reflector panels. This is a modified kyoto solar cooker. It normally only has 1 reflector in the back. I edited 3 more in which is a design I plan on making next.

i appreciate the work you are doing for mexicans who are inhaling too much smoke.

please make their lives better so they dont feel the urge to antpile into my state anymore. i have to move now, and ive been here for 30 years

>>128477
Humans are originally nomads. Moving shouldn't be that bad. A lot of people move like every 2 years...usually leaving angry landlords and unpaid rent. lol

>>128328
Good choice of magazine.

bump for love of solar cooking devices