In reply to Terry Blanton's message of Fri, 1 Apr 2005 16:53:51 -0800 (PST): Hi, [snip] >Mylar. > >Robin van Spaandonk <[EMAIL PROTECTED]> wrote:I would estimate mirror costs >being at least ten times less. [snip] Close. Aluminised mylar as used in toy balloons is too thin, as it wrinkles easily. I estimate about 0.5-1 mm thick would be both sufficiently rigid to remain smooth, and also sufficiently cheap. It may be possible to use a cheaper plastic than mylar. The rigidity of the whole mirror could be maintained, by gluing the aluminised sheet to solid Styrofoam *cast* in a parabolic shape. IOW a parabolic mold is used to cast thousands of identical Styrofoam blocks. If necessary, the Styrofoam can be reinforced with chicken wire.
The whole thing would be very light weight, very rigid, and very cheap to make ($'s per kW, as opposed to $'s per Watt). The mirrors would become the cheapest part of the installation, iso the most expensive part. Most large scale mirrors currently in use have heavy metallic structures supporting the mirrors, which in turn require carefully balanced and machined supports. This is what makes them so expensive. Regards, Robin van Spaandonk All SPAM goes in the trash unread.
