Compress your clay to avoid warping and cracking!
Today I am sharing another useful trick for hand-building with clay- which is compressing your slab before you start working with it. This is another step which up-levelled my process by leaps & bounds!
When I talk about compressing clay slabs, I am referring to the process of applying pressure evenly across the surface of the clay to remove texture and air pockets, but primarily to align the clay particles so the clay is ready to build with. Here's why this practice is a game-changer for any hand-builder:
- Enhanced Structural Integrity: Compressing your clay slab ensures that the particles are aligned/ tightly packed, leading to increased structural integrity. This step significantly reduces the likelihood of your final piece developing cracks or warping during the drying and firing stages.
- Minimized Air Pockets: Air pockets trapped within the clay can sometimes be a nuisance. Compressing the slab helps eliminate these air pockets, resulting in a more homogeneous and reliable clay body.
- Smooth surface: You can get rid of any unwanted texture on the clay slab by compressing your clay with a rib. Usually the clay slab will have the texture of the canvas it was rolled on. Some potters use this texture in their work, while others like me, who like to add additional texture prefer a smooth clay surface. Compressing the clay gives you a smooth surface upon who you can add your own texture or carving.
How to Compress the clay
You can compress clay using the flat side of any pottery rib. In my opinion metal and silicon ribs work better. My favourite is yellow silicon rib from Sheryl mud tools.
To compress your clay slab, hold the rib in your hand with the flat side facing the clay. With the rib held at an angle, go over the clay surface in a sweeping action with medium pressure.
Now medium pressure is subjective- here's how I define my medium pressure- make sure that you press the rib hard enough that it gets rid of any texture on the clay surface. The texture usually is from the canvas you've rolled your clay slab on. But at the same time, make sure that your sweeping action doesn't end up leaving deep marks on the clay surface. This sweeping medium pressure action should be done multiple times in different directions. You may find your slab stretching out a tiny bit, and that's alright.
Once you are done with one side, flip the slab over and compress the other side, as well, in exactly the same manner. And that gives you a nice compressed slab, ready to hand-build with.
Once I religiously started including this as part of my process, I saw a substantial reduction in warping and cracking in my pieces. This was especially true for the large flat plates and platters.
Warping & cracking in large flat forms is a common problem lot of potters face, especially at the beginning. This one step in your process can make a huge difference to your outcome!