Sovereignty Module: Shape the Clay
Complete Ceramics: From Earth to Vessel
Pottery provides storage, cooking, and water vessels essential for civilization. This campaign covers clay sourcing, forming, firing, and glazing.
Chapter 1: Clay Sources and Preparation
| Source | Quality | Processing | Color (fired) | Best For |
|---|---|---|---|---|
| River bank clay | Variable | Wash, screen, wedge | Red-brown | General pottery, bricks |
| Subsoil clay (dig 2-4 ft) | Good | Dry, crush, slake, screen | Variable | General pottery |
| Glacial deposits | Good-excellent | Minimal processing | Gray-white | Fine pottery |
| Decomposed granite (kaolin) | Excellent | Wash, settle, dry | White | Porcelain, fine ware |
| Commercial (bagged) | Excellent | Ready to use | As labeled | All purposes |
Clay preparation: Dig raw clay. Dry completely (sun). Crush to powder. Slake in water (dissolve). Screen through mesh (remove stones, roots). Let settle (heavy particles sink). Pour off excess water. Dry to workable consistency on plaster or cloth. Wedge thoroughly (knead 50+ times to remove air bubbles). Air bubbles = explosion in kiln.
Chapter 2: Forming Methods
| Method | Skill Level | Speed | Symmetry | Wall Thickness | Best For |
|---|---|---|---|---|---|
| Pinch pot | Beginner | Slow | Low | Variable | Small bowls, cups, learning |
| Coil building | Beginner-intermediate | Slow-moderate | Moderate | Controllable | Large vessels, sculptural |
| Slab building | Beginner-intermediate | Moderate | Low (angular) | Even | Boxes, tiles, plates |
| Wheel throwing | Intermediate-advanced | Fast | High | Thin possible | Bowls, cups, vases, plates |
| Mold pressing | Beginner | Fast (after mold) | High | Even | Repetitive forms, tiles |
| Slip casting | Intermediate | Fast (after mold) | Very high | Very even | Complex forms, production |
Coil building: Roll clay into ropes (coils) 1/2-3/4" thick. Build walls by stacking coils in spiral. Score and slip (scratch surface, apply wet clay) each joint. Smooth inside (and outside if desired). Can build very large vessels. Slow but requires no equipment. Oldest pottery method. Smooth or leave coils visible (decorative).
Chapter 3: Firing Methods
| Method | Temperature | Fuel | Time | Equipment | Results |
|---|---|---|---|---|---|
| Pit firing (open) | 1,200-1,500°F | Wood, dung | 2-6 hours | Pit in ground | Unglazed, variable color, fragile |
| Bonfire firing | 1,200-1,500°F | Wood | 2-4 hours | None (open fire) | Unglazed, smoky, primitive |
| Sawdust kiln | 1,000-1,400°F | Sawdust | 8-24 hours (slow burn) | Metal container | Black/carbon finish, decorative |
| Updraft kiln (catenary) | 1,800-2,300°F | Wood | 8-24 hours | Brick/stone kiln | Stoneware possible, good results |
| Downdraft kiln | 1,800-2,400°F | Wood, gas | 12-36 hours | Brick kiln (complex) | Even heat, professional results |
| Raku | 1,800-2,000°F | Gas/wood | 1-2 hours (fast) | Small kiln | Metallic/crackle glazes, decorative |
Pit firing procedure: Dry pots completely (2+ weeks). Pre-heat near fire (prevents thermal shock). Dig pit 2-3 ft deep. Layer: fuel (wood/dung) → pots → fuel → pots → fuel. Light from top or bottom. Maintain 2-6 hours. Let cool completely before removing. Expect 10-30% breakage. Results are waterproof but not as strong as kiln-fired.
Chapter 4: Glazing
| Glaze Type | Temperature | Ingredients | Result | Difficulty |
|---|---|---|---|---|
| Ash glaze | 2,200-2,400°F | Wood ash + clay + feldspar | Natural, variable, beautiful | Moderate |
| Salt glaze | 2,300°F+ | Salt thrown into kiln at peak | Orange-peel texture | Moderate (damages kiln) |
| Slip (engobe) | Any | Colored clay (liquid) | Matte, colored surface | Easy |
| Lead glaze (historical) | 1,800°F | Lead oxide + silica | Glossy, clear | Easy but TOXIC (avoid) |
| Feldspar glaze | 2,200-2,400°F | Feldspar + whiting + silica | Glossy, durable | Moderate |
| Borax glaze (low fire) | 1,800-2,000°F | Borax + silica + colorants | Glossy, colorful | Moderate |
Simple ash glaze: Collect hardwood ash (oak, maple, fruit trees). Sieve through fine mesh. Mix: 40% ash + 40% feldspar + 20% ball clay. Add water to cream consistency. Apply to bisque-fired pottery by dipping or brushing. Fire to cone 6-10 (2,200-2,400°F). Results vary beautifully with different wood species.
Chapter 5: Essential Projects
| Project | Method | Firing | Use | Difficulty |
|---|---|---|---|---|
| Water storage jar | Coil built | Pit or kiln | Store water (2-10 gallons) | Beginner-intermediate |
| Cooking pot | Coil or wheel | Kiln (stoneware temp) | Cook over fire | Intermediate |
| Bowl set | Wheel or pinch | Any | Eating, serving | Beginner |
| Oil lamp | Pinch or mold | Any | Lighting | Beginner |
| Tiles (roofing) | Slab, mold | Kiln | Roofing, flooring | Beginner |
| Pipe (water) | Coil or wheel | Kiln | Plumbing | Intermediate |
| Crucible | Coil (thick walls) | Kiln (high fire) | Metal melting | Intermediate |
| Fermentation crock | Coil or wheel | Kiln + glaze | Food preservation | Intermediate-advanced |
Reference Card
- Wedge clay thoroughly: 50+ kneading cycles. Air bubbles = explosion in kiln. Most common beginner failure.
- Dry slowly: 2+ weeks in shade. Fast drying = cracking. Even thickness dries evenly. Cover thin edges.
- Pit firing: simplest method. Dig pit, layer fuel and pots, burn 2-6 hours. Expect 10-30% loss. Pre-heat pots first.
- Coil building: no equipment needed. Score and slip every joint. Can build any size. Oldest method. Works everywhere.
- Thermal shock: heat and cool slowly. Rapid temperature changes crack pottery. Pre-heat before firing. Cool in kiln.
- Temper: add sand or crushed shell (10-20%) to clay for cooking pots. Reduces thermal shock during use over fire.
- Waterproofing: fire to stoneware temperature (2,200°F+) or apply glaze. Low-fired pottery is porous (good for cooling water by evaporation).
- Test fire: always fire test pieces first. Every clay body is different. Adjust temperature and time based on results.