To build a solar furnace, attach lumber boards to a plywood back panel to form a box, insert the can stacks into the box, drill the hose and air inlet holes at the top and bottom respectively, and paint the surfaces black. Finally, place the furnace in the sun.Continue Reading
Measure and cut a plywood for the back panel, and cut out the sides, top and bottom from a 1- by 4-foot lumber. Glue the boards to the back panel, and secure them together with screws. Seal all the joints with adhesive caulk to prevent air escape.
Caulk ten cans to form a stack, and put it in the box. Repeat the process for the other cans, and let the caulk dry. Drill a hole through the top panel of the box for the vacuum hose, insert the hose, and caulk around the hole. Drill another hole at the bottom of the box, and match it with the bottom of each stack for letting cool air into the box.
Paint the cans and the inside surfaces of the box black and paint the entire exterior surfaces of the box. Black pain absorbs heat from the sun. Cut out a piece of plexiglass that fits the box, and cover it to the box, and then caulk and secure it with screws. Lastly, set the furnace in the sun.