What Equipment Is Used For Ceramics?
Wheel Throwing
The most essential piece of equipment for wheel throwing is the potter’s wheel. The potter’s wheel is a rotating disk that allows potters to raise and shape clay into symmetrical forms. Potters wheels were first used over 5,000 years ago, with early examples dating back to Ancient Mesopotamia and Egypt (Potter’s wheel). While initially rotated by hand or foot, most modern pottery wheels are powered by electricity.
There are several types of pottery wheels used today, including kick wheels, electric wheels, and treadle wheels. Kick wheels are turned by foot power, while treadle wheels use a pedal mechanism. Electric wheels offer variable speed control and reverse rotation to aid in centering clay. They are considered the easiest for beginners to learn on (Potter’s Wheel).
To throw on the wheel, a lump of clay is centered and opened using only the hands. The potter uses techniques like coning, lifting, ribbing, and pulling to raise and shape the clay into the desired form. Skills needed include patience, hand-eye coordination, and a good sense of timing and pressure. With practice, the motions become almost intuitive for skilled potters.
Hand Building
Hand building is one of the oldest and most basic techniques for making pottery. It involves shaping clay by hand without the use of a pottery wheel. Some common hand building techniques include:
Pinch pots – A simple method where a ball of clay is pinched and pressed into a pot shape using fingers. Pinch pots were likely the first type of pottery made, with examples dating back over 20,000 years to the paleolithic era [1].
Coil building – Long ropes or coils of clay are stacked on top of each other and blended together to build up vessel shapes. Coiling likely emerged after pinch pots as a way to make larger and more stable ceramic forms.
Slab building – Rolling out flat sheets or slabs of clay which can be cut, stacked, joined and shaped into pottery. Slab pots allow for more uniform wall thickness compared to pinch or coil building.
Molding – Pressing soft clay into a pre-formed mold to create a specific shape. Plaster, wood, clay, foam and other materials can be used to make molds.
Loop tools and ribs are common hand building tools. Loop tools are used to smooth coils and bridge slab seams. Ribs compress and refine vessel walls and create texture.
Glazing
Glazes are vitreous coatings applied to ceramic wares to provide a glassy, impermeable surface during firing. According to the Encyclopedia Britannica, glazes were first used on stone materials as early as the 4th millennium BC in ancient Egypt (wikipedia.org). Glazes serve both functional and decorative purposes, including sealing the ceramic material against liquids, strengthening it, changing its color and surface properties, and adding decorative effects.
There are many different types of ceramic glazes, but most contain 3 main ingredients: a glass former such as silica or feldspar, a flux like calcium oxide, and an additive like zinc oxide or alumina. The ingredients are mixed together with water to create a suspension that can be applied by brushing, dipping, or spraying (greyfoxpottery.com). Common glaze types include transparent, opaque, matte, glossy, crystalline, and colored glazes. Popular stylistic glazing techniques include dripping, pouring, and layering multiple glazes.
Glazes must be carefully tested and evaluated to ensure they fire properly in the kiln. Factors like thickness, firing temperature profile, and glaze chemistry can greatly affect the final results. With experimentation, ceramic artists can create a wide array of dazzling glaze effects to complement their pottery.
Kilns
Kilns are essential equipment used for firing ceramics to high temperatures to induce physical and chemical changes. Modern electric kilns were developed in the late 19th century, allowing more precise control over firing.1 Kilns heat ceramics gradually according to a programmed schedule to temperatures between 1,830-2,375°F (1,000-1,300°C).
There are several types of kilns used in ceramic firing:
- Electric kilns allow the most control over firing with adjustable shelves, vents, and electronic controllers that follow custom programs. Most models reach cone 6 temperatures (2,200°F/1,200°C).
- Gas kilns burn propane or natural gas for fuel. While temperature control is more difficult, some artists prefer the atmospheric effects from the flames.
- Wood-fired kilns use wood as fuel, requiring constant stoking during the firing. They create unique atmospheric effects but are labor-intensive to operate.
- Raku kilns are small, portable kilns used for raku firing, which involves removing ceramics at red heat and cooling rapidly to induce cracking.
- Pit/sawdust kilns are improvised outdoor kilns constructed from bricks and covered with sawdust during firing.
Choosing the right kiln involves considering the size, durability, temperature range, and features needed for finishing ceramics with the desired surfaces and colors.
Clays
There are several main types of clays used in ceramics, each with their own properties and characteristics:
Stoneware clay is very strong, durable, and watertight, making it excellent for functional ware that will be used frequently. It is fired at high temperatures between 2,200°F and 2,400°F. Stoneware contains different amounts of flux, resulting in colors ranging from grey to brown. It can be decorated using colored glazes.[1]
Porcelain clay is highly refined and free of impurities, firing to a white or near-white color. It is fired at very high temperatures above 2,300°F. Porcelain is lightweight yet strong and can be thinly potted. It has very low porosity, making it an optimal material for tableware.[2]
Earthenware clay contains iron and other minerals, firing to a reddish color. It fires at lower temperatures, between 1,800°F-2,100°F. Earthenware is highly porous and absorbent unless glazed. It’s often used for flower pots, decorative figures, and tiles.[3]
Terracotta clay is an orange-red earthenware high in iron oxide. It’s used for pottery, bricks, and architectural decorations. Terracotta has a coarse texture and can be left unglazed.[1]
Clays can be categorized as earthenware, stoneware, or porcelain based on their firing temperature and properties. The clay body composition and preparation process also impact its plasticity, shrinkage, porosity, color, and texture when fired.
Tools
Some essential tools used in ceramics include:
- Clay extruders – Used to push clay through a die to create a uniform shaped piece of clay. This allows efficient production of handles, feet, or other cylindrical shapes (Source: https://www.potterycreative.com/pottery-tools-names-uses/).
- Slab rollers – Used to roll out slabs of consistent thickness for handbuilding and assembling projects (Source: https://fowlersclayworks.com/basic-pottery-tools-for-beginners/).
- Bats – Canvas or plaster coated boards used to support pottery pieces for throwing and drying (Source: https://www.thesprucecrafts.com/survey-of-basic-pottery-tools-2746328).
- Banding wheels – Rotating tables used to trim and smooth pottery edges when pieces are leather hard (Source: https://www.potterycreative.com/pottery-tools-names-uses/).
- Ribs – Flexible metal or wood tools used for shaping, smoothing, scraping, and compressing clay (Source: https://www.thesprucecrafts.com/survey-of-basic-pottery-tools-2746328).
- Loop tools – Used for detailing, carving, smoothing, and scraping clay surfaces (Source: https://fowlersclayworks.com/basic-pottery-tools-for-beginners/).
Decorating
Decorating ceramic pieces has been done for thousands of years using various techniques. Some of the earliest decorative techniques include impressing patterns with stamps, making incisions, and finger gripping the wet clay. Using slips, a liquid clay mixture, for decoration has been traced back over 10,000 years.
Popular decorating techniques used today include:
Slips – A slip is a liquefied clay mixture applied to the surface of wet or dry clay as decoration. Slips come in various colors and can be used to accent, paint patterns, or coat the entire piece. Engobes are similar to slips but contain clay and other additives like feldspar or oxides to alter the working properties or color.
Sgraffito – This technique involves scratching through a slip coating to reveal the clay color underneath. It was used thousands of years ago across many cultures. Sgraffito creates textured, contrasting colored designs.
Mishima – In mishima, slip is inlaid into incisions made in the leather-hard clay. When fired, the color contrast outlines intricate patterns and images.
Stamping – Stamping tools have been used since ancient times to press repetitive designs and patterns into soft clay. Everything from rope and fabric to carved wood or stone can make stamp designs.
Piercing – Piercing involves cutting out sections of clay to create decorative voids and patterns. This can be done when the clay is soft or leather hard.
Safety Gear
Proper safety gear is crucial when working with ceramics to protect yourself from hazards. Some important safety gear includes:
Respirators – Wearing a respirator like an N95 mask is highly recommended to avoid breathing in fine ceramic dust that can cause silicosis. As recommended on https://ceramic.school/pottery-studio-safety/, respirators should have a tight fit around the nose and mouth to effectively filter out dangerous dust particles.
Goggles – Protective eyewear like goggles or safety glasses should always be worn in the studio. Clay dust can irritate eyes and goggles protect against debris when chipping, grinding, or throwing clay.
Aprons – Wearing an apron keeps your clothes clean while working with messy clay. Look for thick aprons that cover your torso, arms and lap.
Gloves – Gloves protect your hands from irritation and help grip slippery clay. Use heavy duty gloves for handling sharps when altering bone-dry greenware.
Proper Ventilation – Ensure the studio has good ventilation according to https://www.southtexascollege.edu/academics/visual-arts/safety/ceramics.html. Use exhaust fans, open windows, room ventilators and dust masks to avoid build up of clay dust.
Kiln Furniture
Kiln furniture refers to the items placed inside a kiln to support ceramics during firing. Some key types of kiln furniture include:
Shelves – Kiln shelves provide a sturdy, flat surface for stacking and firing ware. Popular options include:
- Cordierite – Made of crystalline magnesium iron aluminium cyclosilicate, cordierite shelves are low cost but tend to break down over repeated firings. They withstand temperatures up to 2300°F (1260°C).
- Silicon carbide – With high strength and thermal shock resistance, silicon carbide shelves hold up to temperatures of 3000°F (1650°C). They are more expensive than cordierite.
- High alumina – Composed of aluminum oxide, these shelves have excellent durability and can withstand temperatures up to 3000°F (1650°C).
Posts – Used to separate shelves and stack ware, posts are available in various materials like cordierite, alumina, and silicon carbide.
Stilts – Small spike-like supports made from alumina, stilts prevent fired ware from sticking to kiln shelves.
Saggars – Boxes made of refractory materials like clay or alumina, saggars protect ware from direct heat and flame.
Kiln wash – A powder that gets mixed with water and brushed onto shelves as a protective coating, kiln wash prevents ware from sticking during firing. Popular options are alumina-based washes which withstand temperatures up to 2300°F (1260°C).
Proper kiln furniture selection ensures even heat distribution, prevents damage, and allows optimal air circulation during firing. (https://www.baileypottery.com/blog/post/the-5-types-of-kiln-shelves-you-need-to-know-about.html)
Storage
Proper storage of ceramic materials, tools, and works in progress is crucial for safety and preventing damage. Here are some key storage guidelines:
Clays should be stored in sealed containers or plastic bags to prevent them from drying out. The storage area should be cool and not subject to major temperature fluctuations. Clays can be refrigerated for short-term storage, but allow to return to room temperature before using to prevent shock.
Greenware, or unfired ceramic pieces, are fragile and should be handled with care. Pieces should be stored on sturdy shelves padded with foam or cardboard to prevent scratches and dents. Avoid stacking greenware directly on top of other pieces.
Glazes must be kept in tightly sealed containers to prevent drying out, contamination, and dust. Store liquid glazes on spill trays or tubs to contain leaks and drips. Label all glazes clearly. Store toxic glazes safely away from open workshop areas.
Kiln furniture like shelves and posts should be kept clean and free of old glaze drips which can fuse pieces together during firing. Store on clearly labeled shelves in an organized manner. Separate posts by size and shape.
Tools should be cleaned after use and stored neatly on racks, in bins, or tool rolls. Store tool handles flat to prevent warping. Sharp tools like ribs and knives should be sheathed or have protected edges.
When not in active use, ceramics workspaces should be kept clean and organized. Proper storage protects the longevity of materials, prevents clutter that could cause accidents, and creates an efficient workspace.