I recently wandered into the world of glass through my university architecture project, which is based around glass. To represent some thoughts I have on incorporating glass into architectural features I decided I wanted to cast a glass object representing a corner piece where the floor meets the wall.
I made a hollow mould with a plaster quartz mix and filled this in with bullseye glass I smashed into small pieces myself. When the programme ended and I opened the kiln, the reservoir on top where I put more frit glass had casted so I presumed that the rest of the inside was casted too. It is important to note that I made sure there was a 5cm thickness around the volume that I wanted to cast just to make sure the mould did not crack open due to the 10kg weight of glass added inside.
Unfortunately, I have just started to remove the mould and noticed that only the first top 4cm of the mould has casted, the rest remain exactly as the frit I put into the mould. It never reached a temperature high enough to even deform. (Please refer to the picture) To be honest, I've never casted glass before and also never used this kiln to cast glass before so I was going in blind. Due to tight deadlines in architecture school I just had to go for it.
This is the schedule I used:
Segment 1; Target 50c. Ramp 50c p/h. Soak 4 hours.
Segment 2; Target 675c. Ramp 220c p/h. Soak 30 minutes.
Segment 3; Target 825c. Ramp 330c p/h. Soak 15 minutes.
Segment 4; Target 480c. Ramp 999c p/h. Soak 8 hours.
Segment 5; Target 85c. Ramp 300c p/h. Soak 4 hours.
Did I use the wrong programme? Was the plaster cast too thick that the heat never made it through the plaster to the glass?
I would really appreciate any thoughts and tips.