Every windshield that gets replaced has to be cut out in some way, shape, or form. After all of the necessary trim pieces are removed, a technician will proceed to cut out the windshield. To cut out the glass, the technician must cut between the glass and the urethane seal. Techniques for doing so can vary, and there are many tools. After the glass is cut, the remaining urethane seal is trimmed to a height of 1 to 2 mm. During one or both of these steps, the pinch weld (the bonding surface for a windshield) can become scratched.
A scratched pinch weld is not the end of the world. In many installations, it's guaranteed to happen. All a technician has to do is prime the area before installing the new windshield. This step only takes a few minutes, and yet, time and time again, it's not done. The end result is the long slow death as rust spreads. It can leave holes in the pinch weld, making it unsafe, and it can continue all of the way up the roof of a vehicle.
If you are reading this as a person looking to get a replacement done on your own vehicle, then I urge you to make sure that whoever does the job primes any damaged areas on your pinch weld. If you're looking to save twenty dollars, make sure you don't end up spending thousands later at a body shop. If you are a member of the auto glass community, then I urge you to make sure that you and your colleagues are doing everything right to insure proper and safe installations. It's sad to see so much poorly done work that shows so little pride in workmanship and reflects negatively on the industry as a whole.
Thanks for stopping by,
David