Solar oven problem-won't heat up?

The focal length of your oven is incorrect or the position of the hot spot is different than where you are placing your food. The solution is too complex to answer here. I can only suggest you Google "build a simple solar oven". The entire interior surface must be reflective, no painted black surfaces.

If you can find an oven thermometer, put that in to see what temperature you're getting. 350 to 400 degrees F is considered good, but that won't toast bread very well.

Make sure that you have a clear cover on the oven - glass or plastic. If there is any airflow at all getting inside, that will cool the oven and ruin it. Also feel the outside of the box. If it feels warm at all, then you need to insulate the outside, including the bottom.

Other answer is true. Foil will just not have the best reflection either, and black absorbs heat , not reflect it at your food. focus is very important.

You may want to look into Fresnel lens cookers for your project. Edmund Scientifc online has lens and kits for them. They really do work, and well. Also, you could make a heliostat out of small mirror squares, search online ,homemade heliostat, and see what you get.

amasci dot com has some article on heliostats and other great science fair type stuff.

have fun and be safe, messing with the sun and lenses can be dangerous

If you live in a hard water area, as I do, the HW cylinder may be choked with lime. After some time this stuff envelopes the heating coil and prevents heat transference. When I changed my cylinder it was a third full of lime which resembled glass! You can check that the heat is travelling around the coil by feeling the flow and return pipes immediately next to the cylinder. Both should be pretty hot. If they are, you need a new cylinder.

Homemade Solar Power Videos - http://solarpower.duebq.com/?pLM

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