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Re: [ATM] 40" mirror some ideas



Like this ?

http://www.cablevision.qc.ca/astro/alex-36ins.jpg

36" dia. x 5" thick, 120 lbs, faceplate to f/4.5, flat back, homemade.

Jean-Guy Moreau


----- Original Message ----- 
From: <vorblesnak@peak.org>


> Keeping in mind the original discussion.  Why not a two stage approach. 
> Cast the front as a 2" x 40" disk of pyrex.  Then create a cellular blank
> by fusing ribs and a back to the pyrex front.  The front will weigh less,
> cool and anneal easier, generally be a better disk to work.  Then you
> could pick up the thickness needed to combat flex by fusing a structure to
> the back.  Do it right and you could slump it to the right curve and save
> on grit and back muscles.

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