Aperture drops are apparently simple to do. But to have control of the process and to be able to get repeatable results is relatively complex. There are various elements that need to be considered when preparing to make one of these. The main technical considerations are:
The height of the drop from the shelf.
Material of the supporting ring or material.
Initial firing speeds
Height in kiln and relation to the distance from the heating elements.
Observation of the progress of the drop.
Arresting the drop
Annealing and cooling.
Finishing the resulting drop.
The above instalments will discuss these in turn.