Technique Links

Glass Loading

Casting

Lifting

Cleaning

Grinding

Polishing

Testing

Integration

Shipping

Glass Lifting Techniques

	Each large mirror blank is very carefully lifted in a special multi-sided handling ring with a lifting rig that provides for broad distribution of the weight of the glass. A 6.5-m mirror blank weighs ~ 12 tons while an 8.4-m blank weighs ~ 19.5 tons.
	The lifting rig contains 36 circular disks 60 cm in diameter that are glued to the front surface of the mirror blank. General Electric RTV silicon glue is used as the bonding agent.
	This image shows a cross-sectional view of the mirror blank (above) which has just been lifted off the oven floor. The gray attachments on the bottom of the mirror blank are silicon-carbide bolts that hold the hexagonal columns in place during the casting.
	The mirror blank has been lifted off the oven floor and will subsequently be rotated from a horizontal to a vertical position.
	This close-up image shows the front surface of the mirror blank and a typical 60-cm disk with RTV silicon glue and silicone tubing that aides in the bonding process.
	The mirror is being lowered into the multi-sided holding ring.
	The holding ring is being rotated from horizontal to vertical while the mirror blank is held in place by RTV glue.