This week, we’re dealing with the following two questions:
1. Can annealed glasses with bubbles or with other defects be tempered?
2. What are the recommended exit temperatures for glass thicknesses from 4 to 10 millimeters?
For this week’s questions, see our full video response below. Special thanks to our experienced engineers Eloi Bottura from Glaston South America Ltda and Tony Neo from Glaston Singapore Pte for sharing their knowledge with us.
As always, remember to learn, share and succeed!
In my opinion you should not temper any defected glass. Every defected glass can break inside the furnace or in the chiller. So, in general it is better to minimize the risk of breaking the glass and leave all defected glasses untempered.
The recommended exit temperature for glass thicknesses from 4 to 10 mm is 630 degrees Celsius. For thinner glass thicknesses you might need to use slightly higher temperatures to achieve the desired fragmentation counts.
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