Try saving your Potato chip bags when you purchase them. They contain the mylar that's needed to build a solar cooker! I'm currently starting to save about 9 of them and start small in building a solar cooker and see how its able to preheat water and if it's a success then maybe I'll try a bigger setup and re-use the mylar for an actual cooker to try periodically! Let me know if anyone else out there has tried this or is going to. I'd like to hear from you

...Willi-C

You can get cheap mylar from "grow-op" supply houses. The reflective quality seems very good. I expect to use this material for a big-dish solar concentrator. Once the system heats water controllably I may attempt to make it serve as a computer controlled oven.

I assume you know of the dangers involved in concentrating sunlight but it bears repetition for any who are new to the idea. Wear eye protection! Concentrated sunlight can be extremely hot and should be handled with care. If you can shade your concentrator reliably or face it away from the sun before approaching it you will be much safer.

Why am I still the mad scientist, even at a high-tech company ;-) ?

I've made a lot of solar cookers (box type with reflectors) using potato chip bag mylar, or coffee bag mylar (check with coffeehouses or stores that sell bulk beans for big bags) for the reflectors. they work great. They do degrade eventually but I think all mylar will eventually. I've done it in the southwest us where the sunlight degradation should have been extreme, the first one I've checked lasted over a year with no change of the mylar needed. Using aluminum foil is really good too for the reflectors. I like the Heavens Flame cooker and mine are a hybrid of his and the regular old Telkes styles.

Some Christmas wrapping plastic should be cheap at the moment. It reflects microwaves too

willi-c,
Buy your chips in multi - pack form. This will give you bigger bags. Also keeps the price down.
Don't forget to exercise daily
regards
dva