At the 2016 AT
course we had a
solar oven challenge. I took an old box, unfolded it and cut the biggest circle I could out of it, maybe 3 feet. Slit it so I could roll it into a cone. Covered it in tinfoil glued down with homemade flour glue. At the base of the cone maid a
cardboard platform to insulate The platform where I was going to set my bottle from the cone surface. On that platform set a black Metal stove pipe end cap where I set a dark beer bottle full of
water . Everything except the cardboard and cap was sealed in an oven bag to prevent convection heat loss. In June, on a sunny day, maybe 60°, pointing it about 25° in front of the sun, the empty bottle was too hot to touch after five minutes and boiled a bottle full of water in about 45 minutes. I won the challenge and the prize was A large organic chocolate bar that I ended up sharing with everyone. Which was fine...because the chocolate bar was organic and lived up to my organic rule: costs twice as much for half the quality... organic charcoal is in that category too