#AskGlaston Episode 45: Why does a white line appear in the center of any broken tempered glass?

This week, we are dealing with the following two questions:

  1. Why does a blurry white line appear in the center of any broken tempered glass particle?
  2. What will happen after the tempering process if we put the coating side in direct contact with the rollers?

For this week’s questions, see our full video response below!

Why does a blurry white line appear in the center of any broken tempered glass particle?

Usually, in the fragmented glass piece there is a different kind of roughness on the surface and the middle area of the glass piece. Therefore, you can see the white haze or the white area in the center of the glass. This happens because there is a compression on the surface and the tension in the middle, and when the glass breaks, roughness in the middle area and the surface is different. In the end, you can see the white area in the middle just because the light reflects differently there.

What will happen after the tempering process if we put the coating side in direct contact with the rollers?

If we are using a coated glass, we usually don’t put the coated side against the rollers. If the coated side is on the rollers, it might get defects.

If the glass is a hard-coated, this possibility of getting defects might be a little bit less. But with soft-coated glass, there is a very high possibility that you will damage or get some defects on the coated surface.

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Antti Aronen

Senior Research Engineer at Glaston

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