RE: ATM New substance mirrors

["Andersen, Clark R." <clanders@utmb.edu>]

>RPM's and f/ratio...)  I just have something for the acrylic mirror thread:

>acrylic/plexiglass has a coef. of thermal expansion of 74 x 10^-6cm/cm/deg
>C., while (plate) glass has 7.  I.E. 10x more expansion.  For those that
>want to put carbon threads into their mirrors:  graphite has a CTE of 3.6 x
>10^-6cm/cm/deg C.  or about half.  I don't know about epoxy, though.  Hope
>this helps some...

>Ryan Hess

I had not seriously considered non-epoxy polymers.  That's a pretty
impressive coefficient for acrylic/plexiglass (are they one and the same
material?).  Would plexiglass need to be melted and formed, or is there a
resin/hardener combination which would permit it to be handled at room temp?

Incidentally, an issue for spin-casting would be the expansion/contraction
upon hardening.  Any figures for this?  I suspect this may be part of the
story with epoxy.

Clark Andersen