broken glass
Jun. 9th, 2003 12:02 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
miriam_eDamn! I was just making my brekky. I washed out my bowl in hot water and then prepared my oats-and-currants brekky pouring the cold milk in last. Then I heard a sound like somebody stepping on potato crisps. I was puzzled until, with a terrible uh-oh feeling I bent down and peered at the bowl. It had fractured in many lines. Now I did the most stupid thing I could: I gently picked up the bowl to carry it to the kitchen so I could put it in the sink. This caused the bowl to fall apart in my hands, cutting them in a few places and distributing milk in a wide path from the fridge room to the kitchen sink.
Stupid! Stupid! Stupid! I should know better!
Cheap glass is cooled rapidly so that the structure is under tremendous stress with the bonds between atoms pulling at one another, stretched like rubber bands almost at breaking point. Glass can actually be very, very strong if allowed to relax those stretched bonds letting the atoms move to better positions of equilibrium. I believe this is how Pyrex achieves its great strength.
I've tried something to see if I can improve these cheap bowls. I've put them in the oven. The idea is to see if heating them over some hours then letting them cool slowly will help ease their atoms into stronger positions. Will it work, I wonder? The trouble is, I will only find out by doing something to a bowl that would normally break it.
Stupid! Stupid! Stupid! I should know better!
Cheap glass is cooled rapidly so that the structure is under tremendous stress with the bonds between atoms pulling at one another, stretched like rubber bands almost at breaking point. Glass can actually be very, very strong if allowed to relax those stretched bonds letting the atoms move to better positions of equilibrium. I believe this is how Pyrex achieves its great strength.
I've tried something to see if I can improve these cheap bowls. I've put them in the oven. The idea is to see if heating them over some hours then letting them cool slowly will help ease their atoms into stronger positions. Will it work, I wonder? The trouble is, I will only find out by doing something to a bowl that would normally break it.
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no subject
Date: 2003-06-10 08:26 am (UTC)Do you understand what I mean about the structure of the glass at atomic level? If anybody would, I'd expect you to.
Glass is really a liquid, but it is a very slow liquid. Glass is also quite elastic. When it is hot and can be squeezed into a mold it has a lot of stretchy forces on it. When it is cooled quickly those tensions are frozen into that shape. A piece of glass may look peaceful, but most glass has a lot of tension inside it. Relieving that tension by heating it up to a high enough temperature for long enough, and letting it cool very, very slowly should make the glass much stronger.
Trouble is I'm not sure how high the temperature should be, how long it should be held there, nor how long the cooling process should take.
What is worse, the quality of the glass may have an important part to play too.
no subject
Date: 2003-06-11 01:07 am (UTC)