That is indeed the question. According to the US National Windshield Repair Association many types of stone damage can be successfully repaired and ultimately depends upon four factors; the size, depth, type and location of the damage.
New technologies are making it possible to repair wider chips and longer cracks than what we have been traditionally able to, but all cases are still determined on an individual basis so it is best to get in touch. At NOVUS Glass, we say that if the damaged area on the windshield can be covered by a credit card, the chances are excellent that it can be repaired.
There are many different types of stone damage, some more easily repairable than others. For example, circular bulls-eye, partial bulls-eye, star breaks, linear cracks, ding and pit types can be easily repaired without having to replace the glass. Multiple cracks and cracks much larger in size will be more difficult to repair.
Generally, if the damage is in the driver’s line of sight, a repair could decrease clarity and reduce visibility so this must be considered by a professional before repair. Another issue would be if the crack happens to be at or very near the windshield’s border as this would most likely affect the strength and integrity of the windshield and it’s original bonding to the surrounding metal frame. This then becomes another issue regarding passenger safety. Other damages that usually lead to a replacement windshield are those on the inside of the windshield, or when there is deep damage on both layers of the glass, complex multiple cracks and long or contaminated cracks.
Laminated glass allows the windshield to remain basically intact even with impact damage and therefore repair is possible. Firstly, any dust or debris should be thoroughly cleaned away with a small vacuum, before injecting a clear, curable resin into the outer layer of glass in order to restore its integrity and improve the appearance of the glass. The resin is then cured and polished to create a smooth surface and at this point, no further damage can be caused by that crack or chip. Typically this takes around 30 minutes, depending on the severity or type of damage. If it is a very deep crack or chip then the intermediate Poly-Vinyl Butyral (PVB) layer may also be damaged, in which case the crack or chip will be slightly enlarged or further deepened in order to make the hole smoother enabling the resin to reach the intermediate PVB layer. The excess resin is removed and then a UV light is applied for curing and hardening the resin.
The original windshield is cut from the edges and removed, along with the seals and glues, leaving behind only the frame. A primer is then spread on the inside of the frame and the new windshield’s edges are coated with a special adhesive sealer with a polyurethane base. After a short time, the windshield is carefully fitted and bonded to the frame.
There are many factors that must be evaluated by a professional before a final decision will be made on whether a windshield can be successfully repaired. Those that cannot be repaired, must instead be replaced. So if you notice that your windshield is damaged, don’t delay seeking out a professional for advice. Quite often cracks will lengthen before you know it, so the sooner you ask for help, the more likely your chance of getting away with an inexpensive repair rather than being caught out by an expensive replacement.