#AskGlaston Episode 12: Can we temper clear and Low-E glass together?

Thanks again for your excellent questions! We’re continuing to provide answers to your challenges with the tempering process. This latest #AskGlaston episode will cover the following two questions:

  1. Can we temper clear glass and Low-E glass together?
  2. Does the tempering line equipment play any role in spontaneous breakage?

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

We process high-volume clear and hard-coated Low-E glass. In our process, the Low-E coating is run against the rollers. Can we temper clear glass and Low-E glass together?

When we are tempering glass, we put it into the furnace where it starts to absorb the heat. In cases when the glass has a coating, it reflects the heating in a different way. So, in order to achieve maximum quality, our advice is to always run one glass type at a time and not to mix Low-E and clear glass.

I am aware about nickel sulfide inclusions and the heat soak test. My question is: does the tempering line equipment play any role in the spontaneous breakage of tempered glass?

Briefly, what is spontaneous breakage? Spontaneous breakage, also known as nickel sulfide inclusion breakage, is caused by the nickel sulfide stones. These are residual stones left inside the float glass from the float glass process in which they can be nickel contaminated. As to the actual question, the answer is that there is no way that the tempering line can affect this phenomenon. The only thing is that if the glass is heat strengthened, the tension is smaller. Therefore, the probability for nickel sulfide breakages with heat-strengthened glass is smaller than with tempered glass.

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About the author

Miika Äppelqvist

Encourages transparent solutions in buildings and ways of working. Seven years of experience from being a glass-man in product management, sales and projects with a focus on glass heat treatment. Believes helping is the best marketing any company can do. Father of two toddlers and a wannabe sportsman with an internal love of ice hockey.