My dad has a pretty good collection of scrap and devices he's bought on sale or at the thrift shop. He is a first rate scavenger. I came to visit my parents for a two week vacation. Looking at his collection I just knew I had to Make something.

After a quick look around I decided on one of the projects he would have certainly vetoed when I was a kid. A solar furnace built from the lens of an overhead projector.

Having recently been to a Maker Faire and greatly impressed with the open source building system called Grid Beam  I decided to incorporate it into this project.


Step 1: Gather Materials

You won't need much for this project and only one item is at all hard to find.
  • A sunny day. I found mine in Southern Colorado in June. 100F in the shade. Plenty of sun.
  • The Fresnel lens out of an overhead projector or back of an RV or other source.
  • Some wood.  4 to 6 feet of 1.5" or 2.0" square stock is ideal. (In reality mine was 1 2/8ths square)
  • A drill or drill press with a 5/8ths bit.
  • Six to Ten 1/4" carriage bolts and nuts. The bolts should be 1/4"-1/2" longer than twice the width of the square stock.
  • A socket or wrench for the bolts.
  • Some bricks are nice to have. Firebricks if you have them.

Thanks for the post, and I have to say that I remember making a solar <a href="http://www.romaniukheatingac.com" rel="nofollow">furnace</a> in junior high as a school project. And I have to say that if you can make it right then they can work really well.

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