Re: [ATM] ATM Digest, Vol 31, Issue 14--- Box beam mirror blank

["Russell Jocoy" <russjocoy@hotmail.com>]

>
>Message: 3
>Date: Sat, 15 Jul 2006 15:36:47 -0700
>From: "Bob May" <bobmay@nethere.com>
>Subject: Re: [ATM] Box Beam Mirror Blank
>To: <atm@atmlist.net>
>Message-ID: <004301c6a85f$28a37bc0$ddadfea9@amd>
>Content-Type: text/plain;	charset="iso-8859-1"
>
>Richard Schwartz (on this list) is making mirror blanks with just
>a large kiln, slumping the faceplate and then cooling and adding
>in the spacers in a triangular pattern and then putting the back
>on top and then rewarming evrerything to fuse the glass together.
>There's another guy (don't remember his name at the moment) that
>is doing square pins between with the same method.  Either method
>appears to work well and produce a lightweight mirror.
>I've done one Richard mirror for him successfully and have
>several more that are on the back burner as they are rather long
>focal length for a Cass so they will end up being Newt type
>mirrors.
>Gluing things together is a sure road to failure as the glue will
>eventually fail and you are then stuck with a failed mirror.
>Bob May
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX


   Bob May is correct.... Glass and Glue only work's in aquariums , and not 
very well.
        My first question on this list was about epoxy sandwiched between 
two pieces of 5/8" plate glass. My initial idea was to make a thicker blank 
to make a telescope mirror. This was over 5 years ago and I have learned soo 
much since that time.. and this list helped me on the way.. The response is 
always
the same ....epoxies, glues, air, water, just don't have the same "thermal" 
properties of the glass..
    Webbed mirrors are the new wave of large diameter mirrors (as far as the 
ATMer) Also the advances in mirror cells has exstended(sp) the limits on how 
far and how thin you can go with any type glass.  Do some homework and 
educate yourself on webbed blanks (you will need a big kiln),
much better, look at large mirror cell structures that can support large 
thin mirrors. Which ever way
you decide make sure your bankcard is fat, and get ready to learn about 
microns,wavelength's, and
actually dealing with glass on a molecular skating rink...    Russ Jocoy

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX


_______________________________________________
ATM mailing list http://www.atmlist.net/