This week we’re dealing with the following two questions regarding the tempering process:

1. Is it theoretically possible to temper clear and Low-E glass in the tempering line at the same time?
2. What causes small interior half-inch cracks on the edges and corners of the glass when tempered?

For this week’s questions, see our full video response below!
As always, remember to learn, share and succeed!

Is it theoretically possible to temper clear and low-E glass in the tempering line at the same time?

Well, if you want to run Low-E and clear glass at the same time with the best quality, that is not possible. Even if you would be able to utilize your latest convection system to get it heated evenly, the challenge will be in the quenching. If you put the same pressure on Low-E and clear glass, they will get different bending results. So, one will be bent in one way and the other in a completely different way.

What causes small interior half-inch cracks on the edges and corners of the glass when tempered?

The cracks usually happen during the pre-processing phase, either when cutting or grinding the glass. The cracks are not visible before tempering because the glass hasn’t heated up. After tempering, when the glass has heated up, it thermally expands and these cracks become visible. Our recommendation is to check the cutting pressure of the cutting line and the grinding force of the grinding line.

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