2. Cracks Due to Scratch In Glass Surface

2) How to determine if glass damage is due to a scratch in the glass surface.

Cracks from a scratch in the glass surface





Glass is produced by fusing together various raw materials such as silica, soda ash, and limestone, and has hardness of 5 to 6 on the Mohs scale (for reference, a diamond has a hardness of 10 on the same scale).

Since earth and sand can contain substances harder than that of glass, glass can be easily scratched by:

^ Fine sand particles

^ Hard metal

^ Rubbing action of contaminated wiper rubbers, or sand partials caught between the wiper and the glass, especially when operating the wipers in a dry condition.

A magnifying glass (10X magnification) must be used to identify wiper scratches as a start point of cracks in the glass.

^ Inspect the wiper paths (may be a single scratch of a group of scratches)

^ Small scratches can cause a small rupture in the outer glass surface, which can lead to a crack from thermal conditions, vehicle vibration during driving, or wind pressure.

A magnifying glass (10X magnification) must be used to identify metal object scratches as a start point of cracks in the glass.





^ Scratches can occur from metal objects such as keys and metal buttons. These scratches are typically sharp and can be found anywhere on the glass surface.

^ Thoroughly examine the entire length of the crack to identify any scratch as a start point.

^ Small scratches can cause a small rupture in the outer glass surface, which can lead to a crack from thermal conditions, vehicle vibration during driving, or wind pressure.

A magnifying glass (10X magnification) must be used to identify scratches caused by a contaminated towel as a start point of cracks in the glass.





^ Scratches can occur from wiping the glass with a towel that has sand particles or dirt on it.

^ These scratches are typically long and have several scratches concentrated together.

^ These scratches can be found anywhere on the glass surface.

^ Thoroughly examine the entire length of the crack to identify any scratch as a start point for cracks in the glass.