Splits on the bottom while fusing
Occasionally, splits can occur on the bottom, while the top is still in one piece. this usually happens when the rate of advance is just a little too fast. On the piece that is shown in this blog –
the clear capping piece allowed the darker glass to split while the top remained unbroken. This kind of uneven heating of glass of different colours shows that the rate of advance needs to be pretty slow on these – much slower than normal.
I looked up the S96 site and could not find a schedule for slumping 3 layers. Slumping a 9mm piece should be possible at 55C/hr, but all the way up to about 630C with no soaks until then, so that everything is heating gradually and evenly. With a 300 mm span you shluld not need much more than 20 mins for it to fall and conform to the mould, unless is it a highly detailed one.