Porcelain is prized for its whiteness, translucency, and refined surface quality — but it has a reputation for being difficult. It is less forgiving than stoneware, has less plasticity, and requires more attention during drying and firing. With the right approach, though, it is an extraordinarily rewarding clay to work with. Here is what you need to know across the three main forming techniques.
Why Porcelain Behaves Differently
Porcelain is made primarily from kaolin, feldspar, and silica — with relatively little of the iron, organic material, and grog that give stoneware its plasticity and forgiveness. This composition gives porcelain its whiteness and translucency but also makes it:
Less plastic — it fatigues faster and has a shorter working window
More prone to warping — it stays soft longer and needs careful support during drying
More sensitive to thermal shock — requires careful attention during drying and firing
More translucent — which shows imperfections, fingerprints, and tool marks more readily
Throwing Porcelain
Work efficiently — porcelain fatigues quickly. Every time you work the clay it becomes slightly less plastic. Develop a rhythm that accomplishes what you need in fewer moves.
Use less water — porcelain absorbs water readily and becomes too soft quickly. Use just enough water to reduce friction — not as much as you might with stoneware.
Pull from the bottom — porcelain walls are less self-supporting than stoneware. Keep walls slightly thicker than you think necessary, especially at the base.
Use a rib — compress and refine the outside wall with a rib rather than relying on your hand alone. It removes excess water and gives a cleaner surface.
Work in short sessions — if a piece is not going well, stop, let it stiffen slightly, and return. Pushing through usually makes things worse with porcelain.
Handbuilding with Porcelain
Let slabs firm up before assembling — porcelain slabs are floppy when fresh. Allow them to firm to a soft leather-hard state on a canvas board before working with them.
Score and slip every join thoroughly — porcelain joins are more prone to failure than stoneware if not properly prepared. Use joining slip or magic water and score generously.
Dry slowly and evenly — porcelain dries unevenly and warps easily. Cover loosely with plastic, rotate pieces regularly, and allow 1–2 weeks of slow drying for complex forms.
Support during drying — support flat bottoms on level surfaces and prop any forms that might sag under their own weight.
Slipcasting with Porcelain
Porcelain is the ideal clay body for slipcasting — it captures mold detail precisely, fires to a dense, translucent body, and produces refined, elegant results. Key points:
Specific gravity is critical — maintain consistent specific gravity (typically 1.70–1.75 for most porcelain casting slips) for predictable casting times and wall thickness. Check before every session.
Do not over-deflocculate — too much Darvan makes the slip watery but dense, which can cause casting problems. Add deflocculant gradually and test.
Demold carefully — porcelain at leather-hard is fragile. Do not rush demolding. The piece should release cleanly from the mold — if it resists, wait longer.
Trim greenware promptly — porcelain trimming works best at leather-hard. Bone dry porcelain is very brittle and chips easily.
I am a visually impaired ceramic artist. I have been making for around 8 years now. I specialize in functional colorful pottery. Mainly nerikome and other decorative processes.
