chipped tempered glass

We have a piece of 10mm tempered glass sized 1x2 meter and it was chipped about 10mm into the glass and about 1 meter along the edge. Our machine had been tested to temmpered glass to meet TUV standard. Does it mean that my glass is not fully tempered or it is the nature of tempered glass? Thanks to the experts.

Guest User
Thu, 18/09/2014 - 13:18

Hi, this is not normal for tempered glass.

You would need to send me a photo of the damage and I should be able to give you a better idea of what was causing the problem.

Unfortunately you really need to deliberately break a piece of glass exhibiting the problem. The point of break with a centre punch should be right at a corner of the glass. This will give you the most uniform break pattern possible, and if it is not uniform then we need to look at what is happening during the heating and quenching.

If the break pattern of the glass looks normal then I suspect that the edge was slightly fractured either during cutting and breakout, or while edgeworking/polishing (overheated) and during the quenching the fracture ran down through the thickness of the glass. If the fractured edge was smooth then it would not cause the glass to fail in the quench.

If the deliberately broken glass shows a poor break pattern (or areas of poor break pattern) then you have a problem with the system.

You can email a photo to me at

Jonathan Barr

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