Here's an idea: quartz requires 1700c to melt which is unachievable for an amateur, but fused quartz becomes syrupy at 1200°C, where a lot of kilns
get up to. Could I cheat the system by using silica gel melted at 1200°c to make fused quartz glassware? Or is the silica gel not actually pure
amorphous sio2?
[Edited on 20-1-2021 by John paul III]
[Edited on 20-1-2021 by John paul III]rockyit98 - 19-1-2021 at 20:48
there is no need. just buy it, not that expensive.UV quartz sleeve / test tube. if you need fused quartz tube, UV water sterilizers have them just be careful it filled with toxic Hg vapor !more
thin but long ones can be found on not working Quartz tube heaters. thin yet shorter ones are in burnt halogen flood lamps (500W to 1kW).
just because you asked, NO! silica gels are not pure .they explode when heated and some may contain toxic Co salts! also, depend on manufacturing lot
of Na impurities can be found.in theory fine SiO2 powder can be used to make stuff by sintering at 900°C, 1000°C, 1100°C, and 1250°C. unionised - 20-1-2021 at 04:10
A major reason for borosilicate and soda glass to exist is that quartz glass doesn't soften. Much like a metal, it gets hot, maybe softens a tiny bit,
and then it's suddenly a liquid. Maybe in an extremely narrow temp range would it be syrupy, right before it melts.
Haven't tried it myself, but that's what I've read.unionised - 25-1-2021 at 10:14
Quartz can be worked like glass, but it has a much narrower (and hotter) temperature range.
A similar idea is how the material called Vycor is produced. A very alkali-rich borosilicate glass is extensively leached with acid leaving behind
porous almost pure silica. It's then heated in a kiln until it starts to soften resulting in slight shrinkage and loss of porosity.
