Compression

To prevent cracks in pottery, especially those dreaded "S-cracks," compression is key. Compressing the clay, particularly the bottom and walls, helps align the clay particles, reduce water absorption, and minimize stress during drying. This process involves pushing the clay inward, causing it to collide with itself and become denser, resulting in a more even and stronger piece. 

Methods for Compressing Clay:

• Bottom Compression:

  After forming the base, compress the bottom using your fingers, a sponge, or a rib tool, ensuring it's flat and of even thickness. A needle tool can be used to check thickness. 

• Wall Compression:

  When throwing, compress the walls by pushing your fingers inward, guiding the clay to collide with itself, creating a denser, stronger structure. 

• Slab Compression:

  When working with slabs, compress them in multiple directions, flipping the slab and compressing again to ensure evenness and prevent cracks. 

Why Compression Matters:

• Reduces S-cracks:

  S-cracks often occur when the centre of the piece is too wet or uneven in thickness. Compression helps to prevent this by ensuring evenness and density. 

• Improves Strength:

  Compressing the clay makes it denser and less prone to cracking during drying and firing. 

• Promotes Even Drying:

  By ensuring evenness in thickness and density, compression helps the piece dry more evenly, reducing stress and the likelihood of cracks.