Re: [ATM] mirrors

["Richard Ozer" <rozer@pacbell.net>]

And the scary part is that I couldn't remember if we had really done this or 
not!!!

Thanks Bill..

R (clearly suffering from early stages of dementia) O

----- Original Message ----- 
From: "Bill Marriott" <bmarriott@pacbell.net>
Cc: <atm@atmlist.net>
Sent: Wednesday, May 25, 2005 4:29 PM
Subject: Re: [ATM] mirrors


> Richard;
>
> Probably a year ago or so, I did indeed polish flat both sides of an ASM 
> 8" blank, when held up to the light, you can see inconsistantcies in the 
> 'color' distribution of the black, with areas of green 'Pilkington 
> technical glass" color showing through here and there.
>
> I then brought it to the Chabot Mirror making lab, and with Richard O, set 
> up a light and a pair of polarizing filters, the glass was illuminated 
> just fine,  and we were supprised to see the glass darken evenly, with no 
> sign of stress or straie.
>
> That was just one piece of glass, btw. Who knows what lurks in other, 
> bigger, ASM blanks.
>
> Regards
>
> Bill Marriott
> VA Optical Labs
>
>
>
>
>
> Richard Ozer wrote:
>
>> Oh yes... one more thing.
>>
>> Considering the lengthy thread on annealing this week and the importance 
>> of testing for stress; one thing that is difficult (nearly impossible) to 
>> do with the ASM product is test it for stress... it's black and cross 
>> polarizers are a useless with an opaque material.
>>
>> However, I remember Bill Marriott was able to flash polish both sides of 
>> a piece of BVC and I seem to recall him getting light to pass through 
>> it.... I may have imagined this; maybe he'll chime in....
>>
>> RO
>>
>> Cec & Cris wrote:
>>
>>> Hi everyone
>>>
>>> My name is Cristian and I have just joined your group.
>>> I'm in the process of grinding out a 250mm mirror(I'm up to the fine 
>>> grinding stage) and I'm already looking into my next project. In 
>>> Australia it's difficult to find mirror blanks, most come from overseas 
>>> and cost a small fortune. Through your links I came across ASM products 
>>> page and I was wondering if anybody out there had made mirrors using 
>>> their products and if they hold their shape due to temperature changes. 
>>> I want to make a 24 inch mirror.
>>>
>>> regards Cristian
>>> _______________________________________________
>>> ATM mailing list http://www.atmlist.net/
>>>
>> _______________________________________________
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>>
>
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