glasuurimist

Glasuurimist is the practice of applying a glaze to ceramic objects to form a glassy, impervious surface, enhancing decoration and functionality. A glaze is a glassy coating that fuses to the clay body during firing, resulting in a waterproof, sometimes colored surface.

Glazes are mixtures of silica, fluxes, and stabilizers such as alumina. Fluxes such as soda ash, feldspar, and borates lower the melting point of silica. Color is added with metal oxides or commercial stains. Historically, some glazes contained lead or tin to achieve opacity; contemporary practice often avoids lead due to safety concerns.

Application methods include dipping, brushing, pouring, and spray coating. Glazes may be clear or colored, transparent, translucent, or opaque, and may be applied in single or multiple layers. Techniques such as underglaze decoration (color applied on the unfired body or under a clear glaze) and overglaze decoration (on top of a fired glaze surface) are common.

Firing characteristics depend on the ceramic body and the glaze. Glazes mature at specific temperatures (low-fire, mid-range, or high-fire), typically within a wide range of cone numbers. Incompatibilities between glaze and body can cause defects such as pinhole defects, crazing, shivering, or crawling; quality control and testing are important.

Safety and regulation: Glazes may contain hazardous substances; lead-based glazes are restricted in many countries for consumer wares. Proper formulation, testing for leaching, and compliance with standards protect users and the environment.

Glasuurimist is a central technique in ceramic art and pottery worldwide, with regional traditions and evolving formulations. In Estonian, the term glasuur is commonly used for glaze, and glasuurimist denotes the practice of applying that glaze.