Re: [ATM] Updated my website - casting a large light weight mirror.

[Ric Rokosz <radicell2@yahoo.com>]

--- Thomas Janstrom <thomas@moiler.com> wrote:

>  
> 
> Basically I'm casting a 16" cellular mirror blank
> 2.5" thick with the face
> plate being about 13mm (1/2") thick, I say about as
> it's contoured to be
> able to take an F3 curve and have a near uniform
> final thickness.
> 

Tom,
 About the lack of info from the Mirror lab - you
might look at the  http://www.SPIE.org web site.The M.
lab published a lot of their work in their various
journals in the late 70's to mid 80's on the lab's
early casting work.You might wont to look up the SPIE
material at most University library enginnering
stacks.

If you ever decide to cast any more blanks consider
going to a triangular cell dseign - that has proved to
be a better design than the hex layout.FEA work done
after the first Mirror lab 8M was cast proved the hex
configuration was too prone to central polishing
pressure.An article about this appeared in one of the
SPIE journals as I recall in the mid 80's.The Mirror
lab hasn't bothered to change due to their huge
investemnet in already existing shop material.

When it comes to annealing the longer the better as
you say but it does chew up the kiln...:)

Ric


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