Building a solar oven that could have the ability to reach 220 F inside 2 hours of direct sunlight is relatively effortless. The solar oven I developed and built has served me well for many years. My oven fits over a platform with wheels to tow about, and is so sturdy it’ll work for decades.
Basically, a solar oven or wax melter is a wooden box having a double – glazed removable lid, propped up at an angle of about 40 degrees. But geometry comes into play here, as that would mean the bottom of the box itself wouldn't produce a level cooking surface. That predicament is overcome by placing a metal plate for the bottom so its level when the box is tilted up. Then the sun can shine directly into the box, so reflectors aren’t essential.
Preparing to melt wax.
The minimum external dimensions of a solar oven are about 21″ wide and 24″ long, with a depth of about 21 inches. When the leveling plate is put squarely while in the bottom, the depth decreases to about 14 inches (assuming an angle of declination of 40 degrees), which is deep enough for most cooking pots. (The bottom level cooking plate will be 9″ above the bottom while in the front, and touching the bottom for the back, reaching from side to side, for a cooking surface of 14 by 18 inches, approximately.). The within back from the solar oven is then automatically set for a reverse angle of 130 degrees, so it reflects solar heat directly to the cooking containers.
Let’s try to make it less difficult to style a solar oven. The drawing at proper shows a solar oven from the side while using minimum dimensions to hold an 8 x 8 inch pot or pan. The pot have got to sit over a surface which is level at 40 degrees. Employing a 9″ wide board as the flat surface, the forward edge is 5″ high on the front side and 8″ back for the bottom. That means the height of the solar oven must be 14″ plus the length 15″ just to hold an 8″ pot level at a 40 degree angle. Utilizing this easy layout method it is possible to design the size of a solar oven to hold the size of pot or pan you intend to use.
The easiest material with which to build the solar oven is ½” plywood. The within is then covered with either 1 ½” thick wood, if obtainable, or so-called “insulation board,” which may be a dense foam with a heavy metal foil on every side. There may be a temptation to utilise Styrofoam, but you would find out instantly that Styrofoam melts at the temperatures of over 250 degrees reached inside a solar oven! Wood is often a great insulator, and if covered with thin sheet metal makes a very sturdy unit. However, the oven becomes also heavy to move about with ease, so mine is mounted over a little trailer (Using a child’s discarded wagon wheels and axles.).
Miles produced his oven portable with wheels from a discarded child’s wagon. Note the thermometer in the very ideal left corner from the frame.
The lid or cover for a solar melter may be constructed utilizing 1″ by 4″ clear board, on edge, about three-eight’s inch Larger in within dimensions than the outside dimensions belonging to the box, so it might be effortless to remove. For glazing I utilised Plexiglas: its far lighter and sturdier than glass. To make the double glazing, I laid the top down on a flat surface, made sure it was square, and nailed on ½” x 3/4″ square molding for the bottom. Then a piece of Plexiglas was cut to fit, laid on the molding, and one more round of molding fitted with Tiny screws, then another piece of Plexiglas, then one more round of molding. When inverted, the top will fit over the box to a depth of about an inch plus a half, which is adequate for strength and security, plus the double glazing of Plexiglas having a ½” air gap has a fine insulation element. I put a grab handle within the center with the back on the lid, just to allow it to be less difficult to maneuver.
How does one elevate the solar oven and allow it to be portable? I utilised the wheels, axles, and tongue from an old child’s wagon that Bette found at the recycling center (A.K.A. “dump”), mounted under a piece of 3/4″ plywood measuring 15 x 30.” The solar oven is fastened near the front belonging to the plywood base applying two door hinges, and near the back I have an 11″ tall piece of plywood that’s also hinged at the bottom. For the bottom from the solar oven, at the back, I placed two left over strips of molding about 3/4″ apart, which offer a slot to the plywood prop. Because the solar oven and also the prop are secured with hinges, it may be stored when not in use inside the down, or flat, position. To keep the glass clean in storage, cut a piece of flat cardboard to fit the glass, then make a tab with duct tape while in the middle of the top so the cardboard can be effortlessly removed.
To utilise the solar oven, I merely raise the back, lift up the prop, set the box down so the prop is in the slot, and it\’s automatically raised to about 40 degrees and ready for use! I can tow it with the tongue handle to move it wherever I want it to become, comfortably turning it directly facing the sun. And I cheated: I drilled a 3/8″ hole via the lid (under the glazing) as well as the solar melter, so an oven thermometer are usually inserted via the hole and read the temperature within the oven.
SOLAR WAX MELTER
People who intend to melt paraffin to make candles need to do one further issue. A melting pan need to be created which hangs from the sides of the oven, is about 3″ deep, and is about 3 inches a smaller amount in length than the length on the box. The front with the pan is “boxed” to retain the wax sliding down, and three ½” holes drilled near the center permit melted wax to pour out directly inside the center in the lowest point for the pan when it elevated to 40 degrees. It is best to have a sheet metal shop stamp one out in your case from galvanized 16 gauge sheet metal.
In use, the melting pan is filled with adequate wax to fill a bread pan, and also the bread pan placed for the flat cooking surface under the front of the pan. The heat belonging to the sun melts enough wax (about 4 pounds) to fill a bread pan in about an hour plus a half, the melting wax operating down the melting tray, due to the holes inside the bottom of the tray, and into the bread pan. Get rid of and replace the bread pan when the temperature is close to 200 F, add even more wax, turn the solar oven to face the sun again, and also you should be able to get 4 or 5 bread pans full per day from Will via September. Set them aside in a safe place – the wax is hot! – and they will cool overnight adequate to comfortably drop out as nice ingots for later use (in the case of reclaiming applied wax for later use), or pour the wax directly into candle molds.
If the wax getting melted is recycled and contains any foreign matter (bits of wick, etc), cut a piece of aluminum window screen and bend the sides so it fits tightly over the bread pan, and all the debris is collected for the window screen as well as the wax is left pure.
Earliest USE OF A SOLAR OVEN
Newly built solar ovens are always an excellent disappointment, as they fog up the glazing inside and won’t heat everything! Don’t get discouraged. Wipe off all of the moisture, and repeat that for about a week, and by then all the moisture within the wood and insulation will have been evaporated as well as the solar oven will begin to work at maximum effectiveness.
CLEANING THE Clear SOLAR COVER
The glass or Plexiglas cover of a solar oven will turn into dirty over time, which reduces the effectiveness or solar heat transmission by a considerable margin. Both the top and bottom surfaces of the top, be they Plexiglas or glass, could be cleaned and polished with a fine automotive cleaner/wax just like Meguiar’s Cleaner Wax, which is as efficient as Plexiglas polish and a smaller amount than half the cost. The auto cleaner/wax will won’t leave any moisture residue to fog up the glass for a couple of days, and as cleaning the glass is a weekly event when in daily use, that's an important thought..
