Choosing a varnish for pottery necessitates the following considerations. What temperature are you firing your ceramics to and how do you intend to use them? Will your pottery be decorative or utilitarian? Additionally, there are aesthetic concerns. Various varieties of ceramic glaze produce remarkably distinct finishes for pottery ware.
Identifying the Function of Your Pottery Is the Primary Consideration When Selecting the Appropriate Glaze. When you hear the types of glazes, such as Matte Finish, Transparent, Translucent, Opaque, Underglaze, and Overglaze, you can rapidly become confused and overwhelmed.
Discharge Temperatures
The temperature of your kiln has the greatest influence on the glaze you select. Low-fire pottery glazes, mid-fire pottery glazes, and high-fire pottery glazes are the three primary glaze varieties.
What exactly is a mid-range glaze?
On porcelain and stoneware clay, the mid-range or mid-fire glaze is used. Stoneware is the most common mid-fire clay, but it is increasingly used for porcelain. Mid-fire glaze temperatures range between 2167 and 2262 degrees Fahrenheit (1186 and 1186 degrees Celsius) (1239 C).
Historically, potters employed mid-fire and high-fire glazes for more earthy hues, but they are now also employing livelier hues. Ceramics Monthly estimates that 75 percent of potters use mid-fire glazes. Mid-fire glaze temperatures typically range from Cone 5 to Cone 6. Glazes with low-fire, mid-fire, and high-fire temperatures mature at different temperatures.
Many potters choose a mid-fire glaze when the object’s function is more important than its appearance. Mid-fire glazes are typically employed for functional purposes because they are more resilient. As technology has progressed, we now have livelier mid-fire glazes, whose hues were previously more muted.
What constitutes Intense Fire Glaze?
High-temperature glazes are fired to Cone 8 to Cone 10 temperatures. Numerous porcelain and stoneware clays employ high-temperature firing and high-temperature glazes. High-fire glaze temperatures will range from 1249 degrees Celsius to 2345 degrees Fahrenheit (1285 C). Similar to mid-fire glazes, the colors may appear muted and drab, but modern technology has enhanced the color spectrum.
Why You Should Select Glaze for Pottery Based on Firing Temperature?
The most essential consideration when selecting a glaze is compatibility with your Choice of Clay. In other terms, a low-fire glaze is required for low-fire clay and so on. Preference and artistic style do play a role, but this is the most important factor.
Any glaze, whether high-fire, medium-fire, or low-fire, should be tested prior to use. This allows you to account for kiln personality and glaze and clay compatibility. The glaze and clay must expand and contract simultaneously.
In order to avoid unanticipated results, it is necessary to consider both the Clay and the glaze. Low, medium, and high fire glazes are created for a very good purpose. The addition of fluxes to glazes causes silica and alumina to melt at various temperatures.
It is always optimal to synchronize the glaze firing temperature to the clay firing temperature. I suggest you first test the glaze on a sample piece to determine how it will interact with the clay to produce the desired effect.
Underfiring Glaze and Overfiring Glaze – What Happens When You Choose the Wrong Pottery Glaze?
Underfiring a glaze occurs when it is fired at temperatures lower than intended. Because the glaze was underfired, it never reaches maturity. The glaze will appear harder, rougher, and dryer than before it was placed in the kiln. Glazes that have been severely underfired will not have a glossy or glassy appearance because they never attained the proper temperatures to vitrify. Also possible are problems such as pinholes.
Fortunately, it is usually possible to refire an underfired vessel at a higher temperature, thereby saving your ceramics.
On the other hand, there are overfired glazes, which occur when a glaze is fired at a higher temperature than the manufacturer intended. Some potters intentionally overfire their glazes to develop crystals on them.
Overfiring glazes is not always problematic, but it can lead to issues such as glaze flaking off pottery. Beginner potters may encounter issues if they overfire, so they should adhere to the recommended temperatures. If a low-fire glaze is fired to a mid-fire (cone 5) temperature, it will dissolve all over the kiln shelf.
What is the Kiln Firing process for Pottery Glaze?
The glaze’s appearance will be altered by a chemical reaction triggered by the kiln’s heat. Ceramics fired in a gas kiln will have a distinct appearance than ceramics fired in an electric kiln. Typically, ceramics fired in a gas kiln lack the brilliance and vibrancy of those fired in an electric kiln.
Choosing a Kiln based on your knowledge of how the kiln will affect your glaze. Electric kilns are designated neutral or oxidation kilns and are more prevalent. Oxidation is a chemical reaction in which electrons are removed from a substance. In contrast, gas kilns are Reduction processes that add electrons.
Gas furnaces use a damper because their combustion requires oxygen. As an experiment, you could partially close the damper, and the oxygen from the clay and glazes will be absorbed by the atmosphere. It would have a novel influence on glazes. With this additional instrument, you are able to create dazzling glaze coloring effects.
Choosing a varnish for pottery necessitates the following considerations. What temperature are you firing your ceramics to and how do you intend to use them? Will your pottery be decorative or utilitarian? Additionally, there are aesthetic concerns. Various varieties of ceramic glaze produce remarkably distinct finishes for pottery ware.