Fossil fuels are becoming scarce and everyone is looking for alternatives’ Apple Inc is considering using solar energy to power its iPod, California’s Ironwood prison is installing more than 6000 solar panels and Boston’s Fenway Park is using solar energy for Red Sox games. After many years on the fringes solar power is soon to be Americas mainstream power source. Panel attached to the roof convert sunlight into electricity and still in the high end as far as expense goes and cannot compete with cheaper, less environmentally friendly fuels like oil and coal. Building a solar furnace yourself is one way of harnessing the sun´s energy without the expense of buying factory made equipment.
Buy or make yourself mirror chips from glass or plastic. Glass is less expensive because the material conducts heat better. The chips should be about ¾” long. If you need to cut them use and oil-fed glass cutter as the cuts are cleaner than a diamond wheel and you will spend less time trimming the edges.
Next use plywood that is ½” thick on the frame. It can be thicker if you are planning to make your solar furnace very wide. Before you assemble the frame, pre-drill the holes for the screws that you will use to secure the mirrors to the plywood.
If you are planning to make you solar furnace very wide make four squares of mirrors. Tilt the mirrors toward the middle of the plywood and use toothpicks secured with hot glue as spacers.
Make or buy hinges for the mirror. You can make them easily by putting a bit of RTV silicone caulk at the mirrors corners, again using a piece of toothpick as a spacer. If you need to adjust the mirrors later you will have no trouble using the screws. Your mirrors will need to be adjusted periodically to get the best focused light possible.
This step is very important. Once you have secured all of your mirrors, cover all of them except a single one near the center. Cover it with Post-it notes. Now take your solar furnace into the sun and use the one uncovered mirror as a reference to focus all of the other mirrors. Take your time and focus the solar furnace directly on the area that you want to heat.