# Throwing and Closing a Sphere

Unit: Advanced Throwing Techniques
Topic: Throwing Doughnut Forms
URL: https://claybook.studio/learn/throwing-and-closing-a-sphere/

# Building a Hollow Ball on the Wheel

The hollow sphere is the essential closed form. Once you can throw a sphere, teapot bodies, closed vases, and doughnut forms all follow the same principles.

## Start with a Cylinder

Throw a short, thick-walled cylinder. The walls need extra mass because you will be moving them outward to belly the form, and then inward to close the top.

## Bellying the Form

*   Place one hand on the inside wall and one on the outside.
*   Apply outward pressure from inside while the outside hand guides the curve. The belly of the sphere develops.
*   Work the belly in a series of gentle passes, not one dramatic push.

## Beginning to Close

Once the body has the width you want, begin collaring the top inward: the same technique as throwing a bottle neck.

*   Use both hands on the outside, applying even inward and slightly upward pressure.
*   Gradually narrow the opening across multiple passes.
*   Keep the walls as even in thickness as possible throughout.

## The Final Closure

To fully close the top:
*   Use a wet finger to smooth and compress the last opening into a tight circle.
*   Or leave a small hole and close it with a tiny pinched patch, blending the edges.
*   Alternatively, leave a small opening and cut it out cleanly to become a lid gallery.

## For a Doughnut Form

To create a torus, insert a round stick or your hand through the centre hole after the form is partially closed, and gently push the clay outward while the wheel turns to open and define the central hole. This requires a great deal of practice to achieve without collapsing the form.

## The Bigger Picture

The hollow sphere is a fundamental form in ceramics that appears across cultures, from ancient [earthenware](https://en.wikipedia.org/wiki/Earthenware) ritual vessels to the refined [porcelain](https://en.wikipedia.org/wiki/Porcelain) teapot bodies of Chinese and Japanese traditions. The collaring technique used to close a sphere is the same skill that defines bottle and vase making at every level of the craft.

## Common Mistakes and Quick Fixes

*   **Bellying too aggressively in one push**: Build volume in gentle passes.
*   **Closing too quickly at the top**: Collar gradually to maintain even wall thickness.
*   **Ignoring balance while shaping**: Check profile symmetry every pass.
*   **Attempting torus center opening too wet**: Wait until partial stiffness for cleaner control.

## Practice Exercise

Throw a sphere progression set: one open-bellied form, one partially closed form, one nearly closed form. Focus on wall consistency and profile symmetry, not final decoration. This sequence trains control and confidence.

## Check your understanding

### Question 1: Why should you start a closed sphere with a thick-walled cylinder?

- [ ] A. Thick walls prevent the sphere from collapsing during drying
- [x] B. The walls need clay mass for bellying outward and then collaring inward
- [ ] C. Thick walls make it easier to cut the form open after firing
- [ ] D. Thin walls crack when the opening is fully closed

Tip: The walls need extra clay mass because they will be moved outward to form the belly and then inward to close the top. Thin walls will not have enough clay to survive both movements.

### Question 2: What throwing technique is used to close the top of a sphere?

- [ ] A. Pinching the top shut by hand while the wheel spins fast
- [x] B. Collaring: applying even inward pressure from the outside in gradual passes
- [ ] C. Pulling the walls upward and inward using an inside hand
- [ ] D. Compressing the clay downward from above using a bat

Tip: Collaring (the same technique used to narrow a bottle neck) is used to gradually close the top of a sphere by applying even inward pressure from the outside across multiple passes.