Vague fusing question.....

[Highland_Tony]

Im trying to find out some information about fusing 2 circular pieces of 19mm thick float glass together to make an approximate 38mm disc for a telescope mirror (another hobby of mine) the disc will be 500mm in diameter. I have no idea on what temperature I need to achieve to do this sucessfully and what kind of annealing I need to do to the finished disc. Its way bigger than anything I have done before and I was wondering if anyone out there with a big kiln could shed some light on what I need to know or point me in the right direction. Thanks

[Zeldazog]

I can remember seeing in one of the Prof Keith Cummings books, a table for schedules for thicker glass, it was probably in this book:

http://www.amazon.co.uk/Techniques-Kiln-Formed-Glass-Keith-Cummings/dp/0713661208/ref=sr_1_1?s=books&ie=UTF8&qid=1333213373&sr=1-1

(if I recall correctly, there's actually a piece about a giant telescope mirror in it too, which took days/weeks to anneal)

I would think the information would be out there on the web somewhere with a bit of time and Googling.  


Edited to add:  I think I also saw some notes on Bullseye Glass website about annealing thick slabs, it will be in the tech notes somewhere.

[dinah46]

This is all I can find for you online http://fusedglass.org/tools/firing_schedules 
I have a printed chart of firing times for different thicknesses and sizes but I can't remember where it came from and, unfortunately, there is no clue on the printout but the site above seems pretty useful.

[Moreton]

This is what you want.

http://www.bullseyeglass.com/images/stories/bullseye/PDF/other_technical/bullseye_annealing_thick_slabs

Anealling thick slabs is a pdf file

Pete

added. www.bullseyeglass.com   will take you to Bullseye's main site with all the info you could ever need on gusing and kiln work . Well nearly all 

[Moreton]

Not sure what "gusing" is  ....just a typo for Fusing.

Pete