Open Firing Ceramics Definition

Most breakage in open outdoor pottery firings occurs because of either moisture in the clay or thermal shock.

Open firing ceramics definition. The final aim is to heat the object to the point that the clay and glazes are mature that is that they have reached their optimal level of melting. The goal of bisque firing is to convert greenware to a durable semi vitrified porous stage where it can be safely handled during the glazing and decorating process. Stoneware is a rather broad term for pottery or other ceramics fired at a relatively high temperature. The firing process is measured in cones a standard unit of measurement that accounts for time and temperature.

It may or may not be glazed. The melting that occurs is on the molecular level. Failure to do so could cause the piece to burst putting you back at square one. It s important that the temperature rises slowly and cools slowly.

When loading the kiln it is important to handle the pieces carefully so the glaze does not come loose. A very fluid slip of high specific gravity obtained by deflocculation and used for forming ware using the casting process. Both of these issues are easily dealt with. Firing is the process of bringing clay and glazes up to a high temperature.

When the ceramic is fired a process known as vitrification takes place whereby the glass phase liquefies and fills the open spaces between the particles. It is bisque fired and then glaze fired. While it is true that pottery fired outdoors breaks more often than pottery fired in a kiln the breakage rate can be drastically reduced by taking certain precautions. Ceramic work is typically fired twice.

This is where the magic happens. The pre firing of a ceramic material to remove all moisture and burn off any oxides and gases. Forming pottery by pouring slip into a porous mould usually made from potters plaster. Whether vitrified or not it is nonporous does not soak up liquids.

When the body cools the glass solidifies and acts to bond the unmelted particles together. If you can have the students take a look at the loaded kiln before the firing and then again when you open the lid. Firing converts ceramic work from weak clay into a strong durable crystalline glasslike form. The glaze firing is the most exciting part of the process for a lot of people.

In essence it s already been fired once and you re just going to put the glaze on it in order to fire it again. The purpose of this initial firing is to turn your pottery into ceramic material. A modern technical definition is a vitreous or semi vitreous ceramic made primarily from stoneware clay or non refractory fire clay.