Re: ATM Desert

[Brad Davy <bdavy@fred.net>]

No one said anything about the non-flat mirror back because for an 8",
it really shouldn't make any difference.  Your source of stress may be
that the silicone pads are too wide.  I recall you said in a previous
post that the pads are approximately 2 inches wide.  Thats probably too
much for an 8 inch mirror.  If your pads are too wide, the temperature
changes during the curing process may have induced the stress.  For my
8", I used three pads at the 50 percent zone that are no more than 1
inch in diameter and used 16d nails as spacers.  I let that assembly
cure for 72 hours in a constant temperature basement before moving it. 
The mirror hasn't budged in over 2 years now and no visible signs of
stress.  

"Slc.Dennis Bishop" wrote:
>  So it looks like if  I ever get  the  8in working,  I'll have to do
> it outside during the winter when it's a high of 32F.

I'm pretty sure at 32f, the silicone will freeze before it cures
properly.  

A possibility might be to use a six or nine point mounting scheme but
use much smaller pads.

Finally, silicone just may not work in your environment.  You may need
to use some rubber pads (computer mouse pad) and mounting clips, or even
a sling to hold the mirror in the cell.

Brad
bdavy@fred.net                  http://www.fred.net/bdavy