[ATM] BVC material properties

[Thomas Janstrom]

Has anyone taken a look in the "photos" section of his website? 

The last two photos give me the creeps! He does seem to be wearing eye
protection but it worries me greatly that he is using a belt sander to do
his bevelling (not the action in and of itself), but that he is doing so a.
dry and b. with out any sort of dust protection..... Well it's his life.

Having seen a guy pass away from silicosis (a lapidarist) not too long ago I
can now heartedly say it's not a nice way to go!

As to BVC I have a F5.6 10"er that I did about 8 years ago now, it still
performs great (although it is on its second coating now). So points I found
when I did it, the material is soft, you can hog to great effect with
120grit SiC. Pits show up more as they appear white on a black background.
When I was figuring it (the material) acted rubbery, not in an elastic
literal way, but in that when you did something that would give a "known"
result with pyrex the effect on BVC was either greater or lesser. This was
not really related to force or duration, it just was. I know this sounds
nonsensical but it is really hard to put an emotive/tactile memory into
words....

Cheers, Thomas.

-----Original Message-----
From: atm-bounces at atmlist.net [mailto:atm-bounces at atmlist.net] On Behalf Of
George Anderson
Sent: Saturday, 9 December 2006 4:01 PM
To: Mitch
Cc: atm at atmlist.net
Subject: Re: [ATM] BVC material properties

More information than this can be had at the manufacturers site 
http://www.ajstelescopeworkshop.ca/ where he (the new manufacturer of 
BVC) gives the same information that used to be on Andre's website.

George Anderson
Montreal Canada

Clear skies and good health

Mitch wrote:
>      Perhaps some tidbits here?
> 
>
http://bi-staff.beckman.uiuc.edu/~melockwo/telescopes/holmes32/mirror32/mirr
> or32.html
> 
> Mike Lockwood's site.
> 
> Mitch
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 

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