Wednesday, 25 May 2016

Scheduling Relates to the Piece

My piece cracked, but I've always used this schedule and it has worked.


One schedule is not for all pieces. A number of factors affect the scheduling of a firing.  Some of them are:

Thickness

  • The thicker the stack of glass, the slower the advance and anneal should be. 
  •  The more layers of glass there are, the slower the rate of advance should be. 
  •  The more uneven the thickness, the slower the temperature changes should be.

Angularity

  • Glass with right angles or even more acute angles needs slower schedules than round or oval shapes.  


Degree of fuse


Contrasting colours

  • Pieces with strongly contrasting colours of glass need slowing in heating and annealing.

Size

  • To some extent the increased size will need some slowing of the schedule. Size becomes more important as you near the edge of the shelf or nearer to the sides of the kiln. Jewellery scale items can have an accelerated schedule.  


Mould base

  • The size and shape of the mould will affect the speed and temperature of the scheduling.         
  • The type and style of mould affect the schedule.  Drapes and especially over steel moulds require slower schedules. 

Position in the kiln

  • The closer the glass is to the elements whether top or side, the slower the schedule must be.
  • The less central on the shelf, the more care must be taken in scheduling.  


  • A kiln constructed for ceramics needs different scheduling considerations than one for fusing.  
  • A kiln with side elements needs more careful firing than one with only top elements.