Schematic diagram of Ceramic temper, highlighting sand or grog, clay, water settling test, material and major working relationships.

Field briefing

Ceramic temper is the deliberate addition of non-plastic material to clay. It turns a promising deposit into a more workable body for vessels, bricks, molds, tablets, or kiln parts.

What you are trying to make

Find an addition that reduces cracking and improves workability without making the clay weak, leaky, or hard to form.

Minimum viable version

A basic version compares small test tiles using clean sand, crushed fired clay, shell, grit, or plant fiber.

Better versions

Better versions sort particle size, keep source records, match temper to object thickness, and retain fired samples.

Prerequisite tree

Materials and sourcing

Sources include sand, crushed old pots, fired clay scrap, shell, crushed rock, chaff, dung fiber, and trade. Recognition focuses on cleanliness, size, angularity, and whether the addition causes cracking or weakness.

Acquisition is local geology and waste recovery. Preparation includes washing, crushing, sorting, drying, and labeling. Substitutes include changing vessel shape, drying slower, or finding a better clay. Geography controls whether clean sand, shell, volcanic grit, or old sherds are available.

Tools and workshop requirements

Useful tools are mortars, sieves or cloth, settling vessels, drying trays, labels, and test molds.

Hazards and controls

Dust and sharp grit irritate skin and lungs; fired fragments cut. Work damp when crushing dusty materials and keep ceramic grit away from food.

Procedure

  1. Select candidate additions.
  2. Wash or crush as needed.
  3. Make small comparable clay samples.
  4. Dry slowly and observe cracks.
  5. Fire test pieces when possible.
  6. Keep the best and worst samples as references.

Verification and quality control

Good temper improves drying and firing without making the object crumble, leak, or tear during forming. Compare break surfaces and repeated batches.

Sources and provenance

Generated expansion for ANA-37. No source pack was used; specific historical and technical claims need human source review.