The kiln’s manual is like your car’s manual – it tells you what the buttons do, but doesn’t tell you how to use them. Going beyond the manual, there are a number of points to consider. To begin with, clays and glazes need to be chosen to have compatible firing temperatures, as well as having the desired appearance and other properties, such as being waterproof on functional pieces.  The kiln needs to be loaded so all pieces are fired evenly, and a firing schedule used that suits the clays and glazes and matches the kiln’s capabilities. And, of course, there will inevitably be pieces that don’t come out as planned, so having the ability to diagnose the causes of problems, whether from the making or the firing stages, is helpful.

Some people worry about the high temperature that a kiln can reach – up to 1300°C – but this isn’t really an issue, as most of the heat is contained within the walls of the kiln. The outside surface temperature can get hot, but even on a poorly insulated kiln it is unlikely to exceed 200°C. Kiln fumes can be a concern, particularly from the organic materials that burn out in the first (bisque) firing, whereas metal fumes are generally not an issue. The level of fumes given off varies significantly with the materials used, especially the clay. Consideration may need to be given to ventilation of the room, or using a kiln vent to ventilate the kiln.

Whilst kilns are essentially very simple pieces of equipment, the heating elements, relays and thermocouple will wear with time, and there may be cracks or glaze runs on the kiln bricks and shelves. Day to day maintenance can easily be done by school staff, generally without needing electrical training, whereas for more complex needs it is helpful to know enough to identify and describe the problem to a kiln engineer before they visit, so they come suitably equipped.