Complete Advanced Coil Building: From Foundation to Monumental Vessels
Coil building allows construction of vessels far larger than any wheel can throw. This campaign covers advanced coil techniques, large vessel construction, surface treatment, and structural engineering.
Chapter 1: Coil Building Fundamentals
Technique
Coil Size
Wall Thickness
Vessel Size
Speed
Basic coil
1/2 inch diameter
3/8 inch
Small (under 12 inches)
Moderate
Fat coil
1 inch diameter
1/2-3/4 inch
Medium (12-24 inches)
Fast
Slab coil
1 inch wide flat strips
3/8-1/2 inch
Large (24-48 inches)
Moderate
Pinch and coil
Varied
1/4-3/8 inch
Small to medium
Slow
Paddle and coil
Fat coils + paddle
3/8 inch (compressed)
Large
Fast
Chapter 2: Large Vessel Construction
Building sequence: 1) Start with thick base slab (3/8-1/2 inch). 2) Score and slip base edge. 3) Apply first coil ring. 4) Blend coil into base on inside. 5) Add 3-4 coil rings. 6) Blend inside joints (leave outside textured or blend). 7) Allow to firm up (15-30 minutes). 8) Add 3-4 more coil rings. 9) Repeat: build, firm, build. 10) Large vessels may take 2-3 days to build (allowing firming between sessions).
Vessel Height
Build Sessions
Firming Time Between
Total Build Time
Under 12 inches
1 session
None needed
1-2 hours
12-24 inches
2-3 sessions
1-2 hours
1 day
24-36 inches
3-5 sessions
2-4 hours
2 days
36-48 inches
5-8 sessions
4-8 hours
3-5 days
Over 48 inches
8+ sessions
Overnight
1-2 weeks
Chapter 3: Structural Techniques
Technique
Purpose
Method
Buttressing
Prevent bulging
Add thick coil on inside at stress points
Tapering walls
Reduce weight at top
Gradually thinner coils as height increases
Corrugating
Add strength
Leave coils visible (corrugated surface)
Paddle compressing
Densify walls
Beat walls with paddle after coiling
Internal ribs
Prevent collapse
Add thick coil ribs on inside
Slow drying
Prevent cracking
Cover with plastic between sessions
Paddle and anvil: 1) After coiling, hold smooth stone (anvil) inside vessel. 2) Beat outside with wooden paddle. 3) This compresses and thins the wall. 4) Compressed walls are stronger and more uniform. 5) Paddle marks can be decorative or smoothed away. 6) This technique is used worldwide for large storage vessels.
Chapter 4: Surface Treatment
Treatment
Stage
Tool
Effect
Smoothing
Leather-hard
Rib, scraper
Smooth, uniform surface
Burnishing
Leather-hard
Smooth stone
Semi-glossy, sealed surface
Texturing
Soft to leather-hard
Stamps, tools, fingers
Decorative texture
Slip coating
Leather-hard
Brush, pour
Colored surface
Carving
Leather-hard
Loop tools, knives
Relief decoration
Corrugated (left as-is)
During building
None (natural coil texture)
Rustic, textured
Chapter 5: Drying and Firing Large Vessels
Challenge
Cause
Solution
Cracking during drying
Uneven drying
Dry very slowly, cover loosely
Cracking during firing
Trapped moisture
Bone dry before firing, slow ramp
Warping
Uneven wall thickness
Consistent coil size and blending
Collapse during firing
Walls too thin for size
Adequate wall thickness, slow firing
Thermal shock
Rapid temperature change
Very slow heating (50°F/hour to 500°F)
Firing schedule for large vessels: 1) Ensure completely bone dry (may take 2-4 weeks for large vessels). 2) Fire very slowly: 50°F per hour to 500°F (water smoking). 3) 100°F per hour from 500°F to 1000°F (quartz inversion). 4) 150°F per hour from 1000°F to target temperature. 5) Hold at target temperature for 1-2 hours (heat soak). 6) Cool slowly: do not open kiln until below 300°F.
Reference Card
Build in stages, allow firming between (large coil-built vessels cannot be built in one session; the weight of upper coils will collapse lower walls that are still soft; allow each section to firm before adding more). 2. Paddle and anvil compresses and strengthens (beating coiled walls with a paddle while supporting from inside with a stone densifies the clay, thins the walls evenly, and dramatically increases strength). 3. Consistent coil size produces even walls (roll all coils to the same diameter before building; inconsistent coils produce uneven walls that crack and warp during drying and firing). 4. Score and slip every joint (the bond between coils must be strong; scoring both surfaces and applying slip before joining ensures a solid connection that will not separate during drying or firing). 5. Dry very slowly (large vessels have thick walls that dry unevenly; the outside dries and shrinks before the inside, creating stress that causes cracks; cover loosely and dry over weeks, not days). 6. Fire very slowly (large vessels contain more moisture and have more thermal mass; rapid firing causes steam explosions and thermal shock; fire at 50°F per hour through the critical early stages). 7. Coil building has no size limit (unlike wheel throwing, which is limited by the potter's reach and the clay's strength, coil building can produce vessels of any size; ancient storage jars exceeded 6 feet in height). 8. Coil building is humanity's oldest pottery technique (before the wheel was invented, all pottery was coil-built; this technique connects modern potters to 10,000 years of ceramic tradition).
