For those aware of my open source solar energy project, I've just finished giving the first free construction workshop at the Riverside community in Motueka, New Zealand, which went really well. Details to be posted to the blog in the next couple days. But the point of this post is; for the previous two prototypes of the device I used kitchen foil for the reflective surface, stretched over the back of a welded wire mesh. This worked actually quite well, but takes a bit of prep and you can put your finger straight through the thing. But during the course of the workshop I was donated some 60 cm x 90 cm aluminium lithographic offset printing plates, which a guy had picked up for $1.50 a piece from a local newspaper. I rang their printers and was told that they were not only aluminium, but of a particularly high grade. His company alone, and it wasn't large, apparently scraps about 900 of these every week. He said it was a very common printing process, tho I don't know about countries other than NZ. I didn't really need to polish them, despite being over three years old, and they were a nice thickness to curve into a parabolic trough. So: very cheap, very highly reflective, can get everywhere and nice to work with. Should take environmental wear and tear well. Perfect? We just make home concentrated solar a lot more achievable?