Read and interpret blueprints or specifications to determine size, shape, color, type, or thickness of glass, location of framing, installation procedures, or staging or scaffolding materials required. Determine plumb of walls or ceilings, using plumb lines and levels. Fabricate or install metal sashes or moldings for glass installation, using aluminum or steel framing. Measure mirrors and dimensions of areas to be covered to determine work procedures. Fasten glass panes into wood sashes or frames with clips, points, or moldings, adding weather seals or putty around pane edges to seal joints. Secure mirrors in position, using mastic cement, putty, bolts, or screws. Cut, fit, install, repair, or replace glass or glass substitutes, such as plastic or aluminum, in building interiors or exteriors or in furniture or other products. Cut and remove broken glass prior to installing replacement glass. Set glass doors into frames and bolt metal hinges, handles, locks, or other hardware to attach doors to frames and walls. Score glass with cutters' wheels, breaking off excess glass by hand or with notched tools. Cut, assemble, fit, or attach metal-framed glass enclosures for showers, bathtubs, display cases, skylights, solariums, or other structures. Drive trucks to installation sites and unload mirrors, glass equipment, or tools. Install pre-assembled metal or wood frameworks for windows or doors to be fitted with glass panels, using hand tools. Cut and attach mounting strips, metal or wood moldings, rubber gaskets, or metal clips to surfaces in preparation for mirror installation. Assemble, erect, or dismantle scaffolds, rigging, or hoisting equipment. Load and arrange glass or mirrors onto delivery trucks, using suction cups or cranes to lift glass. Measure and mark outlines or patterns on glass to indicate cutting lines. Grind or polish glass, smoothing edges when necessary. Prepare glass for cutting by resting it on rack edges or against cutting tables and brushing thin layer of oil along cutting lines or dipping cutting tools in oil. Pack spaces between moldings and glass with glazing compounds and trim excess material with glazing knives.