Can a Utility Knife Scratch Car Window Glass?
2 Answers
Theoretically, it cannot scratch the glass because the hardness of steel is far inferior to that of glass. Types: Car windows are typically divided into four types: front and rear windshields, ventilation windows, heat-insulating side windows, and sunroofs. The front and rear windows of a car usually use curved glass that is both aesthetically pleasing and conducive to visibility, embedded in the window frame with rubber sealing strips or adhered with special adhesives. To facilitate natural ventilation, the side windows of a car can usually be moved up and down or back and forth. Window Materials: As early as 80 years ago, glass was installed on the Ford Model T, using flat glass at the front of the compartment to protect the driver from wind and rain. In the decades since, the glass industry has gradually become involved in the automotive industry, creating various types of safety glass—such as laminated glass, tempered glass, and zone-tempered glass—greatly improving the performance of automotive glass.
With over a decade of car repair experience, I often encounter this concern. Using a utility knife to scratch car glass can indeed leave fine marks, but it depends. Regular side windows use tempered glass, which is harder than utility knives, so minor scratches usually don't cause issues. However, windshields are different—they're made of laminated glass with a softer surface. I've seen cases where someone didn't control the pressure while scraping off adhesive with a blade, leaving white marks on the glass. More importantly, if the knife tip carries sand particles, it essentially becomes a mini sander, capable of even scratching rearview mirrors. That's why it's best to avoid metal tools for cleaning car windows; specialized plastic scrapers are the safest option.
