Thanks DUMBGRUNT. The old term for glass was "vivacious liquid".
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Posted on 05/05/2019 8:54:57 AM PDT by DUMBGRUNT
Nothing fake about it. It also happens with glass tubing, which is why tubing in glassblower’s shops is stored vertically rather than horizontally.
Oh really!
Listen, I got a buddy in Nigeria, a member of the royal family, a great guy, he is willing to cut me into his im/ex business .
For just a few hundred dollars you too could become a partner!...
‘said Northwestern’s Sinan Keten’
‘Wenjie Xia, an assistant professor’
I still remember the days when at least a few Americans did research. I’m getting old, I guess.
That’s what I thought but apparently there’s a tiny little eety weety sub-category of phase states between liquid and solid that glass belongs in. Either it’s pointy-headed nit pickery or something real. I don’t have the expertise to decide.
Thanks DUMBGRUNT. The old term for glass was "vivacious liquid".
One of my all time favorite museums, in part due to the way it is constructed.
What has interested me about glass for decades is glass thickness and thermal shock. Because molten glass cools faster at outer edges than at inner area it fractures or even explodes from thermal shock after it has cooled.
Thick glass has to be annealed (slowly cooled in kiln) to prevent thermal shock. But really thick glass has to be annealed for days even weeks, which is expensive. Thus seldom do you find glass over 2 inches thick.
I have researched ways to make really thick glass without annealing. So far I haven’t found a way, except pure quartz glass which has such low thermal shock properties it can be poured very thick without annealing. But because quartz has such a high melting point it is very expensive to produce and difficult to work with.
Kilning quartz is the most practical way to get molten or even just softened quartz but you are very limited in shapes, and limited in sizes without a very large industrial expensive kilns.
A laser that can concentrate beam to get quartz to melting temperature is possible, and induction is another.
Any other ideas FReepers?
Borosilicate glass over a honeycomb mold was used for the mirror at Palomar, 15 tons of glass(IRC)about 24” thick months and months to cool.
And there are large spalls, from dropped equipment over the years! They still use it.
Yes the first attempt failed they had to anneal slower and longer...they succeed on second attempt.
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