Kiln Space & Loading

Time lapse video of loading up the kiln for a bisque firing

Bisque Firing

Loading up the kiln for a bisque firing is much less precise and much more forgiving than loading it for a glaze firing. Since a bisque firing doesn't require that items aren't touching, you can also fit a lot more things by stacking and nesting your items. Bowls can sit inside bowls, plates can be stacked with edges resting against each other, and smaller pieces can tuck into gaps around larger ones. At this stage, the clay is still porous and unglazed, so there's no risk of pieces fusing together in the heat.

Glaze Firing

A glaze firing is a different story. Once glaze melts in the heat, it basically turns to glass, and if two glazed surfaces touch, they'll fuse permanently to each other (or to the kiln shelf). That means every piece needs its own space, with enough clearance on all sides so nothing drips, touches, or bridges onto a neighbor during the melt.

This also means glaze loads take a lot more planning:

• Spacing: Each piece needs breathing room, so a shelf that held a dozen bisque pots might only hold four or five glazed ones.

• Footing: Feet and bottoms are typically wiped clean of glaze (or waxed beforehand) so pieces don't fuse to the shelf itself.

• Shelf placement: Taller pieces dictate shelf height, so posts often need rearranging between firings to make the most of vertical space without wasting it.

• Glaze behavior: Some glazes run or drip during the melt, so pieces with especially fluid glazes need extra clearance to account for movement and to ensure that the kiln walls and floor aren’t at risk.

Time lapse video of loading up the kiln for a glaze firing