At Hextek Corporation of Tucson, Arizona, we use Gas-Fusion™ to manufacture large lightweight substrates. The term Gas-Fusion™ refers to the process we use to manufacture our glass lightweight mirror blanks. Simply stated, the fabrication starts with several individual components that are fused together and subsequently pressurized to form the final structure. The glass components used to make a blank consist of tubing and plates. We use only Schott Borofloat 33® plates and Duran® tubes.
The quality and consistency of this material is unmatched for borosilicate glass in these forms. A basic blank consists of an assembly of tubes (Duran) sandwiched between two face sheets (Borofloat 33). These components are loaded into a furnace and surrounded by tooling. The glass and tooling combination is heated to the point at which the glass starts to reach the plastic state. Concurrently, the tube ends create a seal by fusing to the faceplates (figure 1). With additional heating, pressurized gas is introduced into all the fused tubes simultaneously centered in holes on each tube through the back plate. The net effect is like expanding soap bubbles (figure 2). When the tubes continue to expand they bump into each other and form a vertical wall that becomes a rib (figure 3).