Float glass technology is quite attractive for cellular glass and writing a blog is good method to think about the advantages and disadvantages. I spent already a blog on a patent and on a paper, which showed that the powder method could be history. One major question is why the flat glass world converted to float glass technology?
Before the float glass process became developed, quality glass needed to be ground and polished to get a smooth surface. Like described in this patent of Pilkington, introducing the hot glass on a molten metal bath with temperature treatment delivered a plan parallel glass pane, which could be used without grinding and polishing. The non-interaction between 100% flat molten metal and molten glass is the main reason for this huge development. However, a fire finished glass surface is not needed for cellular glass.
Like shown in the previous blogs, the tin bath is suggested only to be used as transport carrier during the foaming of the glass. This is a much more expensive solution than the a belt which turns around within the furnace without leaving and so reheating. A glass fleece can be used to avoid sticking of the foam on the steel belt.
The more I think about using a tin bath, I see a lot of advantages evaporating if compared with a steel belt, turning around strictly inside the furnace. Especially the previous paper, which gives an an alternative to the powder method, could be much easier executed by putting the ribbon on a belt, instead on a tin bath. But on the other hand, the float process could become a 100% non-waste process because the ribbon should be perfectly flat and plan parallel. If the non-powder method on a belt would be the second generation, on a tin bath would it become the third generation process. I have the feeling that after almost 90 years cellular glass, we are just at the beginning.