Rib Tool

What it is

A rib is the tool that turns a rough thrown cylinder into a considered form. Run flat against a rising wall, it compresses the clay surface, aligns the particles and closes the microscopic fissures your fingertips leave. That compression is not cosmetic — a well-ribbed wall is measurably stronger and less likely to crack in drying.

The family is large. Wooden ribs come in kidney, oval and teardrop profiles and are the gentlest on the clay, making them the standard for finishing. Rubber ribs flex against a curved wall and give a glass-smooth surface. Metal ribs are stiff and used for aggressive shaping and for shaving a wall thin at speed.

Beyond smoothing, ribs are shaping tools. A rib held at an angle inside a form will flare a rim; held outside it will narrow a neck. A sharp-profiled rib makes a clean shoulder line. Because they are cheap, most potters accumulate a dozen and reach for whichever profile suits the form in front of them.

How to use it well

• Rib both inside and outside of a wall, working from the base upward, to compress evenly.
• Lubricate with a light film of water or slip — a dry rib drags and tears the surface.
• Hold the rib at a shallow angle to smooth; steepen the angle to move clay.
• One slow pass beats five fast ones. Repetitive ribbing over-works the surface and can pull it out of round.

Safety notes

• Sharp metal ribs will cut; keep fingers behind the edge and store them in a roll, not loose in a pocket.
• Discard cracked wooden ribs — the splinter catches on clay and drags across the surface.

Compatible materials

Clay bodies

• All bodies
• Best results with plastic stoneware

Glazes & surface

• Not applicable — throwing tool

Where it sits in the process

Forming on the wheel, from centring to shaping.

Throwing  Wheel & Shaping  Entry tier

Browse every tool in this stage from the Wheel & Shaping category.