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Reflecting materials - Light Reflectivity
This table compares different aspects of potential reflectors for the Papasan Chair Solar Cooker:
|Material||Reflectivity||Weight||Internet price quote||Advantages||Disadvantages|
|Polished Anodized Aluminum||~95%||Light||~$7/square foot||Reflective, lightweight, can be salvaged, structurally durable, easily flexed and shaped||Easily scratched, not super cheap|
|Mylar||>98%||Super light||$30 for a 4'x'50 roll||Super reflective, super light, super cheap||Not good at standing up to the elements, forms 'bubbles' if glue starts to give, requires a rigid backing|
|Aluminum Foil||88% on bright side||Super light||$3.29 for 1.5'x70' roll||Extremely cheap and widely available||Not so reflective, corrodes when mixed with acidic juices, structurally weak, would only last one or 2 sessions|
|Can lids||70-80% (my estimate)||Light||FREE||Widely Available, effective, salvageable, did I mention free?!||Not super reflective, non-uniform shape is labor intensive to use|
|Acrylic Mirror||99%||Medium/Heavy||$78 for 1'x4' plane||Very reflective, nearly unbreakable||Comes in plane, likely very difficult to fit to parabola and still maintain reflectivity, super expensive|
|Glass Mirror||99%||Very heavy||At least $100/square foot||Super reflective, widespread- meaning it could be salvaged||Very expensive new, comes in rigid plane- could be broken to fit paraboloid in mosiac in exchange for a precise focus|
|Astro-foil||76%||Light||$37 for 1'x50' roll||Relatively strong||Not so relective|
- Many potential materials with high reflectivity and strength are only available by special order from industrial companies. Though I have not tried to order or to ask for a donation of these fine products, the manufacturers usually deal in bulk.
In addition, I am not sure a special-order industrial super-reflector meets this projects criteria of salvageablility and wide availability. That said, a bulk roll of high quality reflective material may be a wise investment for the aspiring do-it-yourself solar technician.