Creating the right centred shape on the pottery wheel is vital for a successful throwing session.
Ideal Centered Shape: Aim for a shape with a flat top and only slightly curved sides that meet the wheel head flush. This form provides a stable base for further shaping and ensures the centre of gravity is optimal for opening the clay.
Avoiding Indentations and Bulges: Be cautious not to create a deep indentation at the bottom of the clay. A lower centre of gravity can make the opening process more challenging. Similarly, avoid forming a bulge in the middle of the clay. This would require additional effort to flatten and could complicate the process of forming the base of your pot.
Dealing with Gritty Clay: If you're working with groggy or coarse clay and the surface starts to feel like sandpaper, it's advisable to scrape away the outermost layer. This will make the centring process smoother and prevent the gritty texture from affecting your work. A gritty texture can also indicate that you're spending too much time centring. While it's important not to rush, excessively long centring times can be counterproductive.
Centering Time: Efficient centering is key. Ideally, you should aim to complete the centring process in about 10 to 40 seconds. However, this can vary depending on the size of the clay lump, with larger lumps taking more time. Practice will help you become faster and more efficient at centring without compromising the quality of your centred shape.