GMT mirror casting at UA
GMT3: Members of the Mirror Lab casting team load 38,500 pounds of Ohara E6 borosilicate glass into the oven mold in preparation for spin casting the 8.4 meter diameter mirror blank. The photo was taken shortly before the first layer of glass was completed. The entire proceedure takes three experienced casting team members about eight hours to completely load the glass. L to R: Randy Lutz, casting team manager, and senior staff technicians John Martin and Phil Muir load individual hand sized chunks that have been inspected, graded and weighed previous to the loading operation. The distribution of each glass chunk is closely monitored to guarantee the best result when the glass is heated in the covered spinning oven. Protective eyewear is mandatory, and special gloves are used not only to protect Lab personnel handling the glass, but to keep skin oils and moisture from contacting and contaminating the glass, further assuring the cleanliness of the casting process.