Heaven's Flame Solar Cooker Assembly and testing conducted by Kathleen Jarschke-Schultze copyright1990 by Kathleen Jarschke-Schultze Having some experience with solar cooking and eager to try more I was excited by Joe Radabaugh's simple design. After seeing him demonstrate his solar cooker at SEER '90 I purchased his book, Heaven's Flame, and using it as a guide, assembled and tested a working solar oven. Documentation Joseph has spent the last 15 years designing and using solar ovens. His book, Heaven's Flame Solar Cookers, is easy to read and understand. What is even nicer is that it is interesting and informative. Seven chapters cover the topic thoroughly including history, theory, design and tips on cooking. One complete chapter gives you detailed instructions on building the Heaven's Flame solar cooker. It is simple to make and simple to use. Joe encourages experimentation and modification to your personal preference and needs. There are some hints I have found out through my experience that I will share with you. Cost and materials So far the materials for the oven have cost me $3.37. I used anything that I already had on hand and that kept the cost way down. Had I bought everything I needed it still would have been under $10.00. I already had a piece of glass, left by a previous tenant, that was double thickness (single thickness will do). I built my box to fit the glass, 14" x 22". This is larger than the model in the book, which allows me to use my regular cookware, a point I will discuss later. Joseph's method of construction, using cardboard boxes, does involve some searching. In my correspondence with him, he mentions this as the most difficult part of assembly. Most stores crush their boxes and band them with metal straps in huge bundles, making them inaccessible. I have found that the produce dept. of large supermarkets is likely to have useable boxes if you ask to see them. Also, canned food outlets and some small convenience stores save their boxes. For the larger flat pieces, used for insulation and reflectors, I recommend furniture and appliance stores, their dumpsters are a veritable wonderland of pristine cardboard, and many times it will be of a double thickness. By using three nested cardboard boxes for the main body of the oven the construction is greatly simplified. You will probably use a whole roll of tin foil as it is used for insulation in the main body of the oven and as the shiny surface of the reflectors. Because I live in a canyon, I experience varying degrees of wind every day. To help stabilize my solar cooker I used two sheets of double thickness glass (again on hand) and some silicone caulking to make a thermal pane (using a technique described in the book) to insulate and weight the bottom. Although it was not called for I also found that by gluing a small wooden knob onto the glass door I was able to open and close the hot glass much easier. Following is a list of materials that I used. Those with an (*) asterisk are the things I bought, followed by their prices. * 1 roll of aluminum foil $1.38 * 1 can flat black spray paint $1.99 3 nested cardboard boxes 4 flat pieces of cardboard for reflectors Assorted flat pieces of cardboard for insulation Elmer's glue three panes of double thick glass silicone caulking razor (or sharp) knife string small paintbrush small wooden knob six metal spring clips Cookware Although the book describes an effective method to use recycled jars as cooking vessels I prefer to use my own cookware. Joseph believes that when solar oven use is more wide spread a specific solar cookware will be developed and marketed. I believe it is here. I use the Corning 'Vision' cookware with excellent results. It is an amber colored material that allows you to see the food cooking, reducing the times you open the oven to check the food. Visionware also holds heat incredibly well, aiding the cooking process and keeping the cooked food hot longer. You can place the lid upside down in the pot and stack another on top of it to cook two dishes at the same time. There are also small casseroles available with flat lids that stack easily. In the photos you can see that I have three dishes cooking at the same time. The large casserole contains the main dish, the two smaller are the vegetable and dessert, respectively. I can throw together a quick salad and dinner is done. Clean up is a breeze because nothing ever burns in a solar cooker. Any black pot or pan with a lid works well, my favorites there are cast iron dutch ovens and 'Miracle Maid"cookware. When baking bread or cookies black or dark colored pans and sheets are the best. One must always remember that this is a real oven. You need to have hot pads handy when you open your solar cooker to check or remove the food. Keep your face away from the glass door as you open it as the steam from some foods can burn you. Kid Sized Solar Cooker The increased awareness about solar cooking in our house bore fruit. My husband brought me three small nested cardboard boxes and exclaimed, "Look, a Cabbage Patch solar oven!". Having already made one oven using Joe's directions I didn't need to refer to them again. In one afternoon I had built a small working Heaven's Flame for my niece. It is big enough to cook a single serving size casserole, as you can see from the photo. Cons and Pros The disadvantages of the Heaven's Flame solar cooker are few, but important to be aware of. Since it is constructed of cardboard, for the most part, it must be brought in at the first sign of wet weather. Even a heavy dew point will cause damage, as will setting it on wet ground. The oven itself is light in weight and must be weighted or watched in windy conditions. There is also a simple tie that can be utilized to secure the reflectors to the oven body. To position the oven at a correct angle I used short pieces of 6 x 6 lumber, although rocks or bricks could be used, the wood was easier to move and adjust. The lightness is a plus in that the oven is easily moved by removing and folding the reflectors flat and closing the outer flaps on the box. I used a box with handholds for the outer box to further simplify the task. The lack of cost and ease of construction makes this model oven available to everyone. By being able to choose the size of oven the utility will be suitably matched to your cooking needs. Conclusion You cannot fry food in solar cookers. The ovens never reach a high enough temperature, but just about any other recipe can be adapted for use. Recipes for crock pots need no adjustments. A rule of thumb for solar cooking is that it will take twice as long to cook the dish as in a regular oven. Vegetables cook in their own juice so there is no need for additional water. I have had great success with beans, rice, spaghetti sauce, stews, and anything that benefits from a long slow cooking. You can also bake bread, muffins, bread and rice puddings. The thing I found I really liked was being able to start dinner in the morning and not think about it again until dinner time. It was surprising to me how easily solar cooking fit into our lifestyle. It does take some planning early in the day but you are rewarded with a hassle free, hot dinner when you want it. My testing was conducted in the midst of firewood gathering and Autumn yard work when it came in very handy to have a hot meal waiting at the end of the day. If you are interested in solar ovens but can't afford the manufactured model, I recommend building your own. Heaven's Flame is an easy, informative and affordable book that will get you cooking with the sun in a short time. Your personal experience will convince you of this cooking style's utility and fun. Access Joseph has a small supply of books left. He is rewriting more of his experiences into a revised edition yet to be published. The book is $5.00. You can get a shortened one page version containing the plans for the Heaven's Flame solar cooker by sending a S.A.S.E. and $1.00 to Joseph Radabaugh, POB 1392, Mt. Shasta, CA. Recipes for Solar Ovens Sunshine Chili by Bonnie Reynolds 1 lb. grnd chuck 2 med. onions 1 small green pepper 1/2 cup minced parsley dash of salt and pepper 28 oz. canned tomatoes 1 lb. small red beans (dry) 1 TBSP. chili powder 4 cups V-8 juice In your solar oven, brown ground chuck, onions, pepper, parsley and dash of salt and pepper. Drain well after about an hour, then add tomatoes, red beans, V-8 juice and chili powder. Bake covered about 4-5 hours; serves ten; you may add more V-8 juice as cooking proceeds. Solar Lasagne by Karen Perez Take a quart of spaghetti sauce and mix with 3/4 cup water. Take 1 pint of ricotta cheese and mix with 1 beaten egg. Chop one pound of fresh spinach or thaw two 8 oz. packages of frozen chopped spinach. Slice 1/2 lb. fresh mushrooms. Slice or grate 1 lb. Mozzarella cheese. Have ready 1 pound uncooked lasagne noodles and some Parmesan cheese. Spread some sauce on the bottom of a covered dutch oven, place a layer of uncooked noodles over that. Proceed to layer the rest of the ingredients alternately ending with sauce topped with the Parmesan cheese. Bake covered in a Dutch oven inside a solar oven about 2 1/2 hours. Makes six servings.