Schematic diagram of Grog, highlighting fired clay scrap, clay, kiln firing test, material and major working relationships.

Field briefing

Grog is fired clay returned to the clay supply chain. Broken pots and failed test pieces become a useful ingredient instead of waste.

What you are trying to make

Crush fired clay into sorted particles that mix cleanly into fresh clay and improve behavior for the intended object.

Minimum viable version

A basic version breaks clean fired scraps, removes dirt and glaze-like contaminants if present, and tests the crushed material in small clay tiles.

Better versions

Better versions separate coarse and fine grades, keep clay-family batches together, and record how each grade behaves.

Prerequisite tree

Materials and sourcing

Sources include broken pottery, failed bricks, fired test tiles, kiln lining fragments, and trade waste. Recognition focuses on fired hardness, cleanliness, and whether the source material contains salts, ash, limey inclusions, or weak unfired pieces.

Acquisition is often scavenging from the workshop itself. Preparation includes breaking, crushing, sorting, washing when dirty, drying, and labeling. Substitutes include clean sand, crushed shell, chaff, fiber, or crushed stone. Geography matters less than whether ceramic work already exists nearby.

Tools and workshop requirements

Useful tools are a stone hammer, anvil stone, baskets, sieves, settling vessels, labels, and eye-distance discipline when crushing.

Hazards and controls

Sharp sherds cut and dust irritates. Crush away from bystanders, damp down dusty work, and keep grog out of food vessels.

Procedure

  1. Select clean fired clay scrap.
  2. Break into smaller pieces.
  3. Crush to useful grades.
  4. Remove sharp oversized fragments.
  5. Test in small clay samples.
  6. Store labeled by source and grade.

Verification and quality control

Good grog mixes evenly, does not create large weak spots, and improves drying or firing behavior in a labeled test.

Sources and provenance

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