[ainarssems]

Problem is that they try to do it as quickly as they can to keep costs down. If you scratch through the paint you need to apply primer to prevent corrosion, wait for it to dry, then apply different primers to both car and new windscreen all around the perimeter to help adhesion, wait some more for them to dry and only then glue the windscreen in. Audi also use 2 component adhesive which come in 2 cartridges and mixes as you squeeze it out with pneumatic gun. It hardens quicker and stronger then one component adhesives.

Many fitters ignore any scratches and do not apply any metal primer, don't use any adhesion improving primer but instead use cheap one component primer-less adhesive. This way they can do it 1.5hrs instead of 3-4 and offer cheaper price or pocket more money. This can cause metal corrosion if metal primer was not used and in most severe cases windscreen can fall out couple of years later because all the metal under glue has corroded away.