The final product is graded from AA – sheets with the least distortion, to B – the kind with waves and bubles that we admire today. Double strength cylinder glass (24 oz. per square foot) could be made into 60” x 70”sheets. Sheets of single strength glass (18 oz. per square foot) could be as large as 36” x 50”.
In the early 1960’s Pilkington Glass in Great Britain developed and licensed a way to float molten glass on a bed of molten tin. Both the polished plate glass and cylinder glass processes were phased out. To see how float glass is made go to: How Float Glass is Manufactured
Modern float glass is perfectly flat, flawless and inexpensive. Makers of modern “reproduction glass” artificially add in the imperfections that the original process sought to eliminate. The old glass has an organic charm, a depth and fire-polish, that mechanical float glass can never achieve.