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Build It!
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Tools and Materials
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Corrugated cardboard (large flat sheets from appliance boxes work best)
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Duct tape
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Black tempera paint, powdered
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White glue
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Plastic container, approximately 500 ml
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Oven thermometer
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Aluminum foil (45.7 cm by 7.6 m roll)
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1 large aluminum foil cake tin (15 cm by 30 cm by 8 cm deep)
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1 large (turkey-sized) transparent oven bag
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Shredded paper (for insulation)
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Cardboard box (with flaps, approximately 25 cm by 35 cm by 16 cm deep)
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Plastic spoon
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Utility knife
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Meter stick or metric tape measure
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Felt tip marker
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Sunglasses
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Paint brush, 3 to 5 cm wide
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Oven mitts
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| Solar oven construction materials.
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A. Prepare the Reflective Panels
Organize your workspace. You will need a large tabletop to work on. It is very helpful to have a sink nearby for cleaning up. Arrange your materials and tools so you can get to them conveniently.
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Measure and cut two each of these two panels from corrugated cardboard.
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Using a meter stick and felt pen, draw the outlines of the reflector segments on your cardboard. Use the measurements on the blueprint above.
Using the utility knife, carefully cut out the 4 cardboard segments. Use a ruler or straight-edge to help guide your cuts. CAUTION: Utility knives can be dangerous.
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Smooth out the foil carefully, removing any wrinkles or bubbles as you go
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Remove the top from the white glue bottle and pour approximately 100 ml (about 1/3 cup) into the plastic container. Add 4 tablespoons of water to the glue and stir thoroughly. This will make the glue thinner and easier to spread evenly.
Carefully unroll enough aluminum to completely cover one section. Keep the foil as smooth and flat as possible. Wrinkles and creases in the foil will reduce the efficiency of the reflector. If the cardboard is wider than the foil, use two pieces of foil and plan to join them near the middle.
Using the paintbrush, apply a thin layer of white glue over the entire surface of the cardboard. Be sure to spread the glue right to the edge of the cardboard. Use the flat edge of a piece of scrap cardboard as a squeegee to spread the glue out evenly.
Before the glue dries, place the foil on the cardboard shiny side up, and smooth it down over the entire surface. Try to press out any wrinkles, bubbles, or creases in the foil. If your foil gets badly wrinkled during the gluing process, tear it off and try again with fresh glue.
Using the utility knife, trim the foil so that it is flush with the edge of the cardboard all around. Set the panel aside to dry.
Repeat steps 3 through 5 for the remaining sections.
Rinse the paint brush thoroughly under the tap to remove any glue. The glue-water mixture can be used in Part D below, so put a lid on the container to keep the glue from drying out.
B. Join the Panels
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Cut 8 pieces of duct tape 60 cm long and set them aside (stick them to the edge of the table for easy retrieval).
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Arrange the segments as shown in the photo below, foil side down, wide sections alternating with narrow ones. The narrow end of each should point toward you.
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Carefully position the first two panels, keeping a 2 mm space between them. Position one of your 60 cm strips of duct tape over the joint between the panels. Press it onto the joint, being sure it sticks securely to both panels over its full length.
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Join the third and fourth panels as in step 3 above.
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Carefully flip the joined panels over on the table. This may require two people. Reinforce the joint between each panel using another strip of duct tape.
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Stand your reflector up (foil side in), bringing the edges of the outer two panels together. Have your partner hold the reflector in position while you add the last piece of duct tape.
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Finish the last joint inside the reflector by applying the remaining piece of duct tape.
C. Add the Insulated Box
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Using duct tape, fasten the cardboard box securely to the bottom of the reflector by its flaps. Be sure the box is centered. Add a few strips of duct tape to the corners to make the assembly more rigid.
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Shred some newspaper by tearing it lengthwise into thin strips. You can also use paper from a mechanical paper shredder. Stuff shredded paper into the gaps between the box and the reflector. Leave a little of the paper on the bottom of the box, as shown in the illustration.
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Insulate the box below the reflector using shredded newsprint.
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[CP-4K: Cross section. Corel Draw / jpeg illustration. Caption: Insulate the box below the reflector using shredded newsprint. Copyright: The Pembina Institute]
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Use two coats of black paint to coat the inside of the baking chamber.
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D. Prepare the Baking Chamber
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In the plastic container, use your plastic spoon to mix 2 teaspoons of black tempera paint with one teaspoon of white glue and two teaspoons of water (you can substitute glue and water from Part A above if you had any left over).
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Using the brush, apply the black paint evenly over the inside of an aluminum foil loaf tin. Set this aside to dry. It may be necessary to apply two coats of the paint to ensure full coverage of the aluminum.
[CP-4L: Painting the baking tin. Caption: Use two coats of black paint to coat the inside of the baking chamber. Source: original digital photo. See CD. Photo Credit: The Pembina Institute]
Test It!
(Click to continue)
Download:
 Solar Oven Construction Plans
[PDF Format - 537 Kb]
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