Sourcing for cheap big cast of glass for water jet lens making

Is there any source for cast big chunk of glass pieces ? Like 15x15x15 cms or 6x6x6 inches. May be an glass studio would help but is there such a business like this ?

Umut

These guys might be able to provide what you are asking for. I'm sure the're not cheap.
http://www.artglassproduction.com/CastGlass.htm
or
http://www.robertkaindl.com/CastCrystalFurniture.htm
or
http://image.made-in-china.com/2f0j00TBEaVjvsqzrY/Fused-Cast-AZS-Block.jpg

Casting large pieces of glass is a very time consuming process. After the casting process, it takes weeks to cool, as if it cools too fast it will break.

Greg Lundgren is an artist in Seattle that does a lot of work with thick cast glass. He or his assistants may be able to provide you with information.

http://lundgrenmonuments.com/index.html