Editing Windshield (section)

==Repair of stone-chip and crack damage==
According to the US National Windshield Repair Association, many types of [[stone damage]] can be successfully repaired. Whether the windshield can be repaired always depends upon four factors: the size, type, depth and location of the damage.<ref>{{cite web | url=http://www.carwindshields.info/is-your-windshield-repairable | title=Is Your Windshield Repairable? | publisher=Car Windshield Info | access-date=22 February 2014}}</ref>

===Size and depth===
Repair of cracks up to {{convert|2.4|in|cm|abbr=in|order=flip}} is within permissible limits; automobile glass with more severe damage needs to be replaced. However, this is dependent on local laws. If a crack extends to the edge of the panel then this would compromise the structural integrity of the windshield. Aircraft windshields are designed in such a way that even if a crack were to extend all the way across the panel, the structural integrity is maintained via multiple failsafe methods in both frame and the glass plies. A sacrificial outer layer that cracks rather than devitrifies is the first failsafe.

===Type===
Circular bullseyes, linear cracks, crack chips, dings, pits and star-shaped breaks can be repaired without removing the glass, eliminating the risk of leaking or bonding problems sometimes associated with replacement.

===Location===

Some damages are very difficult to repair, or cannot be repaired:
* on inside of the windshield
* deep damage on both layers of glass due to solar absorption or oxidation.
* damage over rain sensor or internal radio antenna
* complex multiple cracks
* very long cracks (i.e. over {{convert|18|-|24|in|cm|round=5|abbr=in|order=flip|disp=or}} long)
* contaminated cracks
* edge cracks

In cracked windshield repair, air is removed from the damaged area on the windshield with a specified vacuum injection pump. Then using the injection pump, the clear adhesive resin is injected to replace the air in the windshield crack. The resin is then cured with an ultraviolet light. When done properly, the damaged area’s strength is restored, as is 90–95% of the clarity.