1 November 2021.
The ratio we tried was 65% SiO2, 23% Na2O, 12% CaO.
For this we weighed and mixed:
Quartz: 600x0.518=310.8g
Soda: 600x0.312= 187.2g
Lime: 600x0.17=102g
Total 600g of material.
11:45: part of the material is in the crucible, we start the furnace
12:25: 902 °C, the powder is pouring off the walls of the crucible
12:36: 980 °C, soft foam
12:55: we add more material
13:12: all remaining material is added
13:21: 1147 °C, the new material has already turned to foam
13:36: 1183 °C, sample #1
13:50: 1191 °C, large gas bubbles on the foam surface
14:20: 1200 °C, sample #2
14:42: 1200 °C, the glass is not foamy anymore, many bubbles on top, small white pieces inside, sample #3
15:10: 1170 °C, definitely getting clear, sample #4
15:30: we have never seen glass this clear in all our experiments, sample #5
16:01: 1185 °C, sample #6, more bubbly than in the previous one
16:08: We start working with the glass.
Very warm, liquid, even with a fine blow we get instantly very thin walled spheres.
We wait a bit before blowing into it, so it's more manageable. No longer glowing when we do the neck, but still we can form it.
Also, when shaping horses, we find that it is much better and can be shaped much longer (around 50-60 seconds). Great!
We are trying more spheres, cups and other shapes. Lots of mini bubbles in there. Even if it doesn't glow, it can still be shaped.
Then we sat down to evaluate the results.
How this glass is different in use:
- it's platicity last much longer (even if it doesn't glow)
- it heats back up faster
- more liquid
- it had a lot of very small micro-bubbles (maybe that's what makes it seem more liquid?)
- there were small white pieces in it (maybe we could sieve the materials before mixing)
- not as foamy as the first attempt
- the colour needs to be checked later because it looked yellowish when working
- looked smirly to some but not to others
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