To: 
Reply-To: "Scott Berfield" 


Since I think I have a shot at actually finishing my mirror in this decade,
my thoughts are turning again to the mirror cell. I have a full scale
design for a 6 point cell all laid out and ready to go, but the more I
think about it the more it seems like there should be a better answer than
all that aluminum.

I have searched the archives and found many references to using astro-turf
type cells and these seem to be a very neat solution. The one complain I
see anywhere is that the air flow around the mirror would be limited.

I am currently polishing on a bed made from a Home Depot plastic
"grass" doormat. This is covered in stiff plastic
"blades" which are arranged in small circles. When polishing,
even with considerable weight, the mirror does not shift appreciably on
this mat. Like a bed of nails, the hundreds of support points add up to
very even support.

Since the mirror is held some distance off the substrate, and since the mat
has regular perforations (app. 1/4" holes regularly spaced), it seems
that airflow to the back of the mirror could be ensured by mounting the
whole thing on a stiff perforated backing plate. A fan could be used to
either blow or suck (not sure which would be better) air across from the
sides or up through the middle. The mirror could be retained at the edge
using clips or RTV. The whole thing would be light and cheap and very quick
to construct.

Are there flaws here I am missing?

Scott

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Don't worry about people stealing your ideas. If your ideas are any good,
you'll have to ram them down people's throats.
- Howard Aiken

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