how bored are you with looking at this yet?
after about 20 minutes it looks like this and pretty much stays this way. you can see the side of the crucible if you look hard enough.
never try this at home. i prefocused the camera then stuck my hand into the exhust. OH & S lookout! heh heh heh .. nah as if, i had it higher than it hurt. ;)
this is how when you open the lid the crucible sits with in. cool. no hot. cool.
and looking above again. seeing the inport really swirls the fire round.
after cooking my batch at ~1050ºc for 8 hrs, and having run out of lpg gas, i cracked it open. note the use of piss weak gloves. it's touchable, but only briefly, more fibre would help with this.
the batch recipe was taken from 'The science and archaeology of materials. an investigation of inorganic materials' p.51 - 70% silica, 25% soda ash, 5% calcium oxide. hooray
so having picked up the crucible, i then tipped the molten glass into a bucket of water to frit it
the glass was only just beginning to fine out, and is still pretty seedy. but most of it came flowing nicely
you can kinda see the glass in the bottom there, it has a vague blueish tint to it, which i really like.