Packing the Kiln Smartly
A well-loaded bisque kiln is a dense, efficient kiln. Because bisque-fired pieces have no glaze, they will not fuse to each other, which means you can pack them far more tightly than in a glaze firing. This is one of the great advantages of the bisque step.
The Golden Rule of Bisque Loading
In a bisque firing, clay can touch clay. You can stack pots inside each other, nest bowls rim to rim, and fill every available cubic centimetre of space. No piece of kiln furniture needs to separate pots from each other, only from the shelves and kiln walls.
This is the opposite of glaze loading, where every glazed surface must be kept separate.
Nesting
Nesting means placing smaller pots inside larger ones. A large bowl can hold several small cups inside it. A cylinder can have a smaller cylinder inside it. Each nested piece reduces the number of shelf levels you need.
Rules for nesting:
- The pots inside must clear the rim of the outer pot; they cannot protrude above it, or the shelf above will hit them.
- Nesting works best with similar forms: bowls inside bowls, cylinders inside cylinders.
- Do not overfill a nested form; you still need to be able to retrieve pieces after firing.
Stacking Rim to Rim
Two bowls of the same diameter can be placed rim to rim. The upper bowl rests on the rim of the lower, and both are supported. This doubles the number of pieces per shelf level.
Bisque Packing Checklist
Before closing kiln:
- Confirm nested pieces clear shelf above
- Keep peep/cone view unobstructed
- Verify no piece touches kiln wall/elements
Dense loading still needs airflow and visibility.
Keep Exploring
Dense bisque loading is possible because unglazed clay does not undergo vitrification at bisque temperatures, so surfaces cannot fuse together. For more on the kiln structures that support all those nested pots, the Wikipedia article on kilns covers the design of both intermittent and tunnel kilns used in studio and industrial ceramics.
