I liked the simplicity of the CooKit design so I hope you don't mind if I follow your lead. I made a cooker with some titanium sheets and polycarbonate mirror sheets that were leftover scraps from other people's projects. The first thing I did was to draw a parabolic curve on each titanium sheet. Visit Mr. Mike Scirocco's site to download his excellent program that calculates the numbers for any parabolic curve you might desire. It is freeware. I drilled and tapped holes alternating, first on the inside then the outside, the thickness of the polycarbonate on each side of the curve. To hold the polycarbonate in place, I used 4-40 stainless steel screws for the inside and 4-40 stainless steel threaded rod on the ouside. The two pieces of polycarbonate meet at the vertex of the curve. It's a good thing that it was two pieces, as the polycarbonate was not very cooperative about getting bent into a parabola. The polycarbonate sheets are constrained and forced to follow the parabolic curve at the top and bottom edges, but they bow outward through the middle. A thinner sheet of polycarbonate would have been much easier to work with but the thicker sheet supports itself better structurally. I hope the bowing may actually help for cooking food by spreading the heat over a larger area instead of the thin line that a parabolic trough would make. A Pyrex bell jar makes a seal on top of a flat, round piece of glass. Another scrap titanium tube, 7 1/2 long x 5 inches in diameter x .065 wall and painted on the outside with black BBQ paint is used for a bread container. A 5 inch diameter glass with an AR coating sits on top of the titanium tube. I am sure you could use aluminum for the tube and aluminum sheeting for the top and paint it all black on the outside and achieve similar results. A large size windshield reflector goes in the front. A few bricks help shape the windshield reflector to direct more sunlight to the bell jar, much like the Cookit design. The bell jar is a budget buster, but glass plates could be put into a framework and substituted for the bell jar, just as W. Adams (see Solar cooking timeline) did when he made his solar cooker in Bombay India in 1876.
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Mike Pool has lived in Canyon, Texas (latitude of 35 degrees north and 102 degrees west...
Summary I liked the simplicity of the CooKit design so I hope you don't mind if I follow your...
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|current||22:31, March 15, 2009||2,048 × 1,536 (597 KB)||Mike Pool||I made a cooker with some scrap titanium sheets and leftover polycarbonate mirror sheets. I liked the simplicity of the CooKit design so I hope you don't mind if I follow your lead. I drew a parabolic curve on each titanium sheet and drilled and tapped|