Flocculation is the process by which fine particles of clay or ceramic materials suspended in a slurry (a liquid mixture of clay, water and other additives) join together to form larger aggregates, called "flocs". This is achieved by adding a flocculant (such as vinegar, calcium chloride or other chemical substances) that modifies the surface charge of the particles, favoring their electrostatic attraction.
As the particles clump together, the mixture increases in viscosity, becomes more stable at rest and less prone to settling. This control over consistency and thixotropy is essential in the preparation of engobes and glazes, ensuring that they are applied more uniformly and that pigments or components do not separate during storage. In addition, flocculation facilitates the control of the fluidity of mixtures in techniques such as casting, helping to obtain more homogeneous pieces with controlled thicknesses.
Interesting Fact
In the casting technique, controlling slip flocculation is critical. A slightly flocculated slip can shorten casting times, allowing the material to adhere more quickly to the mold walls, creating parts with more uniform thicknesses and reducing defects related to particle settling.
Helpful Tip
Add the flocculant little by little, mixing well and checking the consistency of the slip. Too much can turn a useful mixture into a mass that is too dense and difficult to handle.
