Plaster Bat

What it is

Plastic bats are rigid and cheap, and they hold a pot firmly while you throw it. Their weakness is that they are impermeable: moisture can only leave the pot from the top, so wide plates and platters dry unevenly and crack at the rim.

A plaster bat solves that by being porous. The disc wicks water out of the base of the pot while the top dries, so drying happens from both directions at once and the whole piece shrinks at a more even rate. Plates and large shallow bowls are the classic case, but the technique also helps with anything you want to leave on the bat and come back to the next day.

Plaster bats are made by casting in a ring mould, usually 30–40 cm in diameter and 3–4 cm thick. They need a wheel head with pins or a bat-mate system to stop them spinning off, since plaster is slick and has no friction of its own.

How to use it well

• Soak a new bat briefly before first use so it does not steal water aggressively from the first pot.
• Dry bats standing on edge, never stacked flat — trapped moisture warps them.
• Wipe the pot free from the bat when leather-hard; do not lever a wet pot off plaster.
• Store bats in a dry rack; a saturated bat is useless until it dries out again.

Safety notes

• Cast plaster in a well-ventilated area; the exotherm gets genuinely hot.
• Never let plaster dust enter clay or glaze — a single chip causes lime pops in a fired piece.
• Keep a dedicated plaster bucket and tools; cross-contamination with clay ruins both materials.

Compatible materials

Clay bodies

• All bodies, especially for plates and platters

Glazes & surface

• Not applicable — forming accessory

Where it sits in the process

Preparing and homogenising clay before forming.

Wedging  Clay & Preparation  Entry tier

Browse every tool in this stage from the Clay & Preparation category.