Chemically tempered glass is a great deal stronger than thermally tempered glass (up to 10x stronger than untreated glass vs. up to 2x, for an incredibly reductive yet illustrative oversimplification)
With the caveat that this is very much not my field (I just think it’s neat): I believe you wouldn’t see much of a benefit - they are different methods of achieving the same result (putting the surface of the glass under tension), and while chemically strengthened glass gives a more uniform result which gives greater strength, subsequently heat tempering that glass would likely not compound the effect. I also suspect that it would be exceedingly difficult to design a process where you could get the benefit of both techniques at once - chemically tempered glass requires a long cooling period, which is the inverse of the process to produce heat tempered glass.
Yep, prince rupert* drops are thermally tempered glass. As I understand it (again this is not my field, I just think it’s neat), prince rupert drops aren’t “frail” at any one point exactly - the long tails are just as strong as the rest, but because they have such a tiny cross sectional area (thus the force you apply isn’t distributed across a wide surface area) you’re able to overcome the strength of the glass. That’s why a failure there causes a cascade, because the force is otherwise evenly distributed throughout the whole surface. Because the glasses don’t have a similar feature where the cross section becomes miniscule, they’re not going to be significantly more or less frail at any one point.
Ah super cool! I worked as an engineer in an aluminum plant in the past, and I am always so blown away about how differently ceramics and metals behave.
Chemically tempered glass is a great deal stronger than thermally tempered glass (up to 10x stronger than untreated glass vs. up to 2x, for an incredibly reductive yet illustrative oversimplification)
Are they mutually exclusive? I would love to see tempered glass combined with chemically hardened glass for an even more durable dinner set?
With the caveat that this is very much not my field (I just think it’s neat): I believe you wouldn’t see much of a benefit - they are different methods of achieving the same result (putting the surface of the glass under tension), and while chemically strengthened glass gives a more uniform result which gives greater strength, subsequently heat tempering that glass would likely not compound the effect. I also suspect that it would be exceedingly difficult to design a process where you could get the benefit of both techniques at once - chemically tempered glass requires a long cooling period, which is the inverse of the process to produce heat tempered glass.
This is the idea behind a Prince Rupert Drop, yeah? So do the glasses have a point where they’re frail? Like the lip of the rim or something?
Yep, prince rupert* drops are thermally tempered glass. As I understand it (again this is not my field, I just think it’s neat), prince rupert drops aren’t “frail” at any one point exactly - the long tails are just as strong as the rest, but because they have such a tiny cross sectional area (thus the force you apply isn’t distributed across a wide surface area) you’re able to overcome the strength of the glass. That’s why a failure there causes a cascade, because the force is otherwise evenly distributed throughout the whole surface. Because the glasses don’t have a similar feature where the cross section becomes miniscule, they’re not going to be significantly more or less frail at any one point.
Ah super cool! I worked as an engineer in an aluminum plant in the past, and I am always so blown away about how differently ceramics and metals behave.