It's done by taking the flat glass, heating it, and 'drooping' it over a form. Then the surface is blasted with air, through holes in the form and above it, to temper it. In a message dated 5/18/2005 1:21:09 PM Eastern Standard Time, pottsf at msn.com writes: I'm trying to figure out how you make a curved piece of glass by floating it on some liquid.