# Why Throw in Sections?

Unit: Advanced Throwing Techniques
Topic: Sectional Throwing for Large Pots
URL: https://claybook.studio/learn/why-throw-in-sections/

# The Weight Limit of a Single Throw

Every potter reaches a point where they want to make a pot bigger than they can physically throw in one session. Centering 5 or 6 kg of clay is hard work, and above a certain weight the clay starts to behave differently: it slumps under its own weight before the walls have time to stiffen.

**Sectional throwing** (also called coil-and-throw, or adding on) solves this problem by throwing the base section first, letting it firm up to leather hard, then adding a coil of fresh clay to the rim and throwing that coil upward to extend the walls.

## When to Use Sections

*   Pots taller than about 40 cm are candidates for sectional throwing.
*   Large storage jars, floor vases, and statement vessels almost always require this technique.
*   It is also used to correct proportions: you can see the full base form and decide how much taller you want to go.

## What You Need

*   A bat so you can move the piece without distorting it.
*   Patience: each section must reach leather hard before you add the next.
*   Fresh, well-wedged clay for the added coils.
*   Slip or water for the join.

## Timing Is Everything

The base section must be firm enough to support the weight of a new coil without collapsing, but not so dry that it will not bond. The sweet spot is **soft to firm leather hard**: the clay holds its shape when you press it lightly, but still feels cool and slightly damp to the touch.

## The Bigger Picture

Sectional throwing has been used for centuries to create monumental ceramic vessels, from ancient Greek [earthenware](https://en.wikipedia.org/wiki/Earthenware) storage jars to the large [stoneware](https://en.wikipedia.org/wiki/Stoneware) crocks of European and American traditions. The technique bridges the gap between wheel throwing and hand building, combining the precision of the wheel with the additive logic of coil construction.

## Common Mistakes and Quick Fixes

*   **Adding coils while base is too wet**: Wait for soft-to-firm leather hard before building upward.
*   **Waiting until base is too dry**: Rehydrate join zone lightly and trim to fresh surface if needed.
*   **No bat workflow for large pieces**: Keep forms on bats to reduce handling distortion.
*   **Rushing growth in one session**: Plan sectional builds over multiple controlled stages.

## Practice Exercise

Throw one base section and test three join timings on separate pieces: soft leather hard, firm leather hard, and near-dry. Track cracking and join strength after bisque. This identifies your best timing window.

## Check your understanding

### Question 1: What is the main reason potters use sectional throwing for large pots?

- [ ] A. It uses less clay than throwing a large pot in one go
- [x] B. Clay slumps under its own weight above a certain height; sections let each stage stiffen first
- [ ] C. Electric wheels cannot centre clay heavier than 2 kg
- [ ] D. It produces thinner, more even walls than single-throw large pots

Tip: Very tall or heavy pots cannot be thrown in a single session: the clay slumps under its own weight before the walls firm up. Sectional throwing builds the height in stages, letting each section stiffen before continuing.

### Question 2: At what stage of dryness should the base section be before adding a new coil?

- [ ] A. Completely bone dry so it is as rigid as possible
- [x] B. Soft to firm leather hard: holds shape but still cool and slightly damp
- [ ] C. Still soft and plastic, just as it was when first thrown
- [ ] D. After bisque firing: then the next section is thrown separately and glued on

Tip: The base should be at soft to firm leather hard: firm enough to support a new coil's weight without collapsing, but still cool and slightly damp enough to bond with fresh clay.