A less difficult method of making a blank would probably be the so called "fused cellular"blanks,
composed of 1/2" thick pyrex sheet ,faceplate with "ribs" fused to back of faceplate could be done at lower temps in a kiln,softening point is around 1850F and working point 2300F,perhaps around 2000-2100F the ribs may fuse to faceplate?,maybe use ceramic blocks to hold up ribs with faceplate on top of rib structure,heat until ribs fuse to plate and proceed to anneal cycle.
I know that pyrex sheet is pretty expensive,i was quoted a price of $1500 for a 25"x40"x2" sheet,have not checked the price on 1/2" thick sheet yet,but i know the price goes up dramatically with increased thickness.
Ive wondered if an acetalene torch and thin pyrex rod could be used to weld the ribs to the faceplate? thermal shock would probably crack the plate and/or ribs,if this method was successfull the blank could then be annealled in a kiln to relieve stress produced in the welding process.
It would be interesting to try this on a small scale,with a square grid structure of ribs like illustrated in newport glass works catalog,with an open back(no backplate).

• Re: fused cellular blanks - crockett - February 7, 2001 - 02:29 UTC
• Re: fused cellular blanks - bobmay - February 7, 2001 - 06:22 UTC
  • Re: Re: fused cellular blanks - stevec - February 7, 2001 - 21:06 UTC
    • Re: Re: Re: fused cellular blanks - louielouie - February 8, 2001 - 00:45 UTC
      • Re: Re: Re: Re: fused cellular blanks - stevec - February 8, 2001 - 06:31 UTC
• Re: fused cellular blanks - louielouie - February 16, 2001 - 20:23 UTC
  • Re: Re: fused cellular blanks - louielouie - February 16, 2001 - 20:28 UTC
  • Re: Re: fused cellular blanks - louielouie - February 16, 2001 - 20:32 UTC
    • Re: Re: Re: fused cellular blanks - louielouie - February 16, 2001 - 20:38 UTC
  • Re: Re: fused cellular blanks - stevec - February 17, 2001 - 07:19 UTC
    • Re: Re: Re: fused cellular blanks - louielouie - February 17, 2001 - 17:25 UTC