The panes of glass are fitted after painting and lacquering the car bodywork. In days gone by, the front and rear windscreens were fitted into the bodywork using a profile made of an elastomer that surrounded the glass. A cord-like tacky elastomer sealant was then applied to improve the seal.
Since the start of the 1970s, so-called direct glazing has been increasingly used. Moisture curing 1-component (1-C) polyurethane adhesives, or alternatively modified siloxanes (MS) polymers are used for this. Besides providing an excellent seal, the advantages of this technology are that larger panes of glass can be used and this reduces the overall weight of the car bodywork. This is because the glass panes become a structural material due to the adhesive curing as an elastomer. The rigidity of the structure therefore increases and this so allows thinner metal sheets to be employed.