Discover the different types of sculpting clay with distinct characteristics that you need to get familiar with if you're interested in learning the fine art of clay sculpting.
Sculpting is one of the greatest forms of fine art. It gives you an opportunity to bring your idea to life. The solid form of a sculpture helps in delivering your idea and concept in a stronger way so that your message is heard by masses.
Sculptures are representational. They are a perfect way to take the idea that’s in your head and move it to a physical, tangible space. In addition, they are a perfect addition to any empty space. Sculptures are a powerful form of art, which is why you are most likely to find the greatest sculptures in well-known palaces and ancient, cultural heritage sites. Even today, if you wish to add a touch of elegance, power, and formality to any interior, having sculptures included in the décor is the most promising way of achieving all of that.
Clay sculpting is the art of shaping, casting, or carving a moldable material. It is a form of visual art that requires concentration, attention, dedication, and above all, vision. It is a fairly time-consuming activity. It operates in three dimensions (3D).
Originally, the process of sculpting used carving and modeling with metal, ceramics, stone, wood, and other materials, but in the modern era, there are no restrictions or limitations regarding the material and processes used. Numerous types of materials are used for sculpting today, with the most popular being clay.
You must be aware of the clay you used at school when you were young. That clay is not the only type of clay used in sculpting. There are many types of sculpting clay which you may not have known about until now. If you are developing an interest in sculpting, the first thing that you should have knowledge of is the many types of sculpting clays that are available today.
Table of Contents
- Testing Clay Suitability for Sculpting
- Characteristics of Sculpting Clay
- Types of Sculpting Clay
- Sculpting Techniques
Testing Clay Suitability for Sculpting
Numerous types of clay are available today, but not all of them are suitable to be used in sculpting. If you find a clay that you want to use for sculpting, it is better to test it before buying it in bulk. Testing clay’s suitability for sculpting is fairly straightforward.
All you have to do is form a cylinder with the clay which is approximately four inches in length and half an inch in diameter. Bend this cylinder and observe closely. If you see cracks in the clay, the clay is too dry, or it has too little elasticity to be used for sculpting. However, if the cylinder bends smoothly, without showing any signs of sand or rock, you can use it for sculpting. In the latter case, you might not need any refining as well.
Characteristics of Sculpting Clay
There are certain characteristics that clay should possess to be considered suitable for sculpting. These include:
- It should be smooth (free of sand and rocks)
- It should be easy to bend
- It should offer the required stiffness for sculptures
- It should be resistant to heat shock
All clay types have different characteristics. The different types of sculpting clay have been listed below.
1. Water-Based Clay
As the name indicates, water-based clay is clay mixed with water. It is inexpensive and quite easy to work with. Water-based clay dries out fast as the water content evaporates. The fast-drying of water-based clay is one of the features that make it popular.
It was first developed to be used in the sculpting of the animatronic models for Disney. This clay was known as WED clay (Walter E. Disney). The properties of this type of clay are quite similar to many oil-based clay types that are popular today.
Water-based clay is suitable for small projects. Since it tends to dry out if kept for too long, it is best used for projects that use up the clay before it dries out. However, in case you have to store water-based clay for future use, it should be packed in an airtight bag with a light spray of water once a month. Make sure that you do not make the clay too wet because it sticks and breaks apart.
- Water-based clay is cheap
- Water-based clay is easy to work with
- It is smoothed easily
- Water-based clays are extremely pliable
- It can stay workable for a long period of time if it is kept in a sealed bag
- Water-based clay can be kiln-fired to maintain its shape
- Water-based clay tends to dry out fast if left uncovered
- You need to spray water at least once a month if you are storing water-based clay for a long time
- Water-based clay shrinks as it slowly loses its moisture with time in storage
- Water-based clay is not suitable for long projects due to its fast drying property
Air-dry clay is usually water-based clay. As you can tell by the name, air-dry clay can be dried using the air around you, and it does not need to be kiln-fired. It cures in air, without the need for exposing the sculptures made with this type of clay to high temperatures.
Air-dry clay is commonly used as modeling clay. The time taken for the clay model or sculpture to dry completely depends upon the thickness of the prepared item. It can take anywhere from a few hours to a week to dry thoroughly.
The best thing about using air-dry clay for your sculpting project is that you don’t need any special sculpting tools. A simple rolling pin and a knife are all you will need to get the project done. Moreover, it can be colored with acrylic paints, tempera, inks, and marker pens.
Air-dry clay offers a lot of space to try different things. Rubber stamps leave a fairly deep and a prominent impression on air-dry clay.
It is one of the most common types of clay that is used in arts and crafts to make models and sculptures (that do not need too much detailing).
2. Oil-Based Clay
Oil-based clays are made of a combination of oils, waxes, and clay minerals. The primary benefit of oil-base clay over water-based clay is that it will not dry out even when placed uncovered in dry conditions. Items or sculptures that are made with oil-based clay are not ceramics as they cannot be fired.
Since oil-based clay contains oil, its malleability is affected by the temperature. The viscosity of the oils varies with temperature, and therefore, by increasing or decreasing the temperature, you can alter the consistency of the clay, and hence, its malleability.
Oil-based clay is most popular with animation artists (used in Claymation) because it can be re-used, and hence, allows for its bending and moving.
If you wish to make silicone molds, you have to use clay that does not contain sulfur. Sulfur-free varieties of oil-based clays are available easily.
- Oil-based clay can be worked into fine details
- It is suitable for making detailed clay sculptures
- It does not stick to the skin or any other surfaces
- Oil-based clay does not dry out in the air, and therefore, you don’t need to complete your project hurriedly. You can take as much time as you wish. It is the best clay for lengthier projects
- It is expensive
- It cannot be heated in the oven
- Oil-based clay is not very pliable when it is removed from the packaging, but it softens with body heat
Plasticine is an oil-based modeling material. Its main ingredients include clay, oil, and a binder (usually clay flour). It is a trademark name of oil-based clay. Plasticine was developed by William Harbutt, who was an art teacher and wanted to prepare clay for his students that did not dry. The terms plastilina and Plasticine are the common names you will come across when looking for oil-based sculpting clay. These are used as generic terms for modeling clay in the present day.
Plasticine-type clay is the only true-modeling clay because of its distinct properties. It stays workable and soft, unlike the water-based clay and wax. It does not dry or hardens. It is available in a wide variety of colors which can be used as purchased or can be blended to form new colors. The best thing about Plasticine-type clay is that it does not stick to your hands or the working surfaces.
Most Plasticine-type clays have sulfur, which makes them unsuitable to be used for silicone mold making.
Plasticine-type clay comes with all the pros that any oil-based clay has. It can be shaped easily and worked into details. It is the best option if you want to make a finely detailed sculpture. Unlike water-based clay, Plasticine-type clay cannot be fired. If it is exposed to excessive heat, it will melt to form a greasy heap of messy material.
Polymer clay is a generic term that is used for human-made sculpting/modeling clay. This type of sculpting clay is soft and pliable but only till it is heated. Upon heating, polymer clay hardens permanently. If not heated, polymer clay never dries out.
Polymer clay is made up of polyvinyl chloride (PVC) that is mixed with a stabilizer, plasticizer, lubricant, and different pigments that give it a wide array of colors that it is available in. The uncured form of polymer clay is simply a vinyl mixture with filler that forms a dough, but as soon as it is cured, it becomes solid vinyl.
Polymer clay is suitable to be used by kids, home-based hobbyists, and professional sculptors and model-makers. It is a safe type of clay to use; however, there are certain precautions that need to be kept in mind.
- Do not burn polymer clay. The fumes produced may cause difficulty in breathing and irritation in the breathing passageways
- Do not eat it. Polymer clay should only be given to children under adult supervision to make sure that they do not eat it
Polymer clay can be used to make whatever you want, with fine details. It can be used to make jewelry, sculptures of living things, decorative items (crockery, boxes, etc.), and other items that you can imagine making with clay.
Polymer clay has a number of advantages over other types of sculpting clay.
- It is inexpensive
- You don’t need any special ovens or a kiln to cure sculptures made with polymer clay. You can simply cure it in your home oven.
- It is suitable to be used by any level of artists, starting from kids right up till professional sculptors
- You don’t have to worry about the clay hardening or drying out while it is still in process. This clay never dries out, so you can easily use it for lengthy projects
Epoxy clay comes as two separate components; epoxy resin and epoxy curing agent. Epoxy clay does not harden as long as the two components are not mixed together. Upon the mixing of the two components, an exothermic reaction is kick-started that promotes the curing of the clay.
Epoxy clay comes in different colors. However, the array of colors is not as wide as polymer clay. What makes epoxy clay different from polymer clay is that it remains soft as long as the two components are not kneaded together. Once it is done, it takes about 2 to 3 hours to harden. This means that epoxy clay is self-hardening and does not need to be fired in an oven.
However, because of the short time for which it stays soft after kneading the two components together, it is not suitable to be used for projects that would take long hours. What makes epoxy clay an ideal type of sculpting clay is that it forms very hard objects. Polymer clay, although suitable for longer, detailed objects, cracks if it is exposed to heat (even direct sunlight can crack it). This is not the case with structures made with epoxy clay.
Epoxy clay does not fade, even if it is placed outdoors under direct sunlight. Coating sculptures made with epoxy clay with a UV protective layer will further preserve its color. Epoxy clay can be used to make sculptures and objects for your aquarium; so it is safe for fish.
Epoxy clay is one of the best sculpting clays not because of its strength but also because it can be colored with almost any types of paints – acrylics, oil paints, spray paints, alcohol inks, and what not!
Although epoxy clay is more expensive as compared to polymer clay, it is totally worth the cost.
Another type of clay that is used for modeling is dough clay (popular as PlayDough). Dough clay can be made at home using basic ingredients such as oil, water, cornstarch, flour, and cream of tartar. It can be dyed in a color of your choice with the help of food color.
It is one of the least expensive types of clay that are used to make sculptures and models. However, their use is limited to children and for making temporary structures as this type of clay cracks upon drying. This makes it unsuitable to be made into lasting items and sculptures. If you wish to preserve the form of a sculpture you made using dough clay, you can do that by simply baking the sculpture in an oven.
Ceramics are made of clay that has been baked or heated to attain a permanent shape. Pottery clay contains only clay, while ceramic clay contains other materials along with the clay itself. Ceramic clay is classified into five different classes, which are:
- Earthenware clay
- Stoneware clay
- Ball clay
- Fire clay
- Kaolin clay
Earthenware clay is the earliest type of clay that has been used over the years by potters. It is also one of the most common types of clay found today. This clay is quite popular with sculptors because of its incredible characteristics.
Earthenware clays are highly plastic, which makes them very easy to work into different shapes. This clay can be sticky. At lower temperatures, earthenware clays achieve their optimum hardness. This is due to the presence of mineral impurities and iron.
Earthenware clays are found in different colors. When moist, they can be found in orange, red, yellow, and light-gray colors. After they’re fired, earthenware items are orange, red, white, or medium-gray in color. The color of the fired item depends upon the mineral impurity content and the type of firing that was used. One of the most popular types of earthenware clay is Terracotta, which means ‘baked earth.’
Stoneware clay comes after earthenware clay. It needs to be fired at higher temperatures as compared to earthenware clay. When stoneware clay is fired to maturity, it becomes chip-resistant, sturdy, and suitable to be used in baking, cooking, and to make sculptures for gardens. The structures made from stoneware clay are extremely durable.
Items made from stoneware clay are denser and heavier as compared to objects made from earthenware clay. It gives the objects a darker and textured look after firing. Stoneware clay objects can withstand hot and cold temperatures and are quite durable.
Ball clay is another type of ceramic clay that is used to make ceramics and other sculptures. Ball clay is highly plastic, and it contains a few mineral impurities. However, ball clay cannot be used alone because it shrinks during drying and frying. It is useful when mixed with other types of clay to increase their plastic character and workability.
Fire clay matures at a very high temperature. Its characteristics vary. This type of clay does not have a lot of mineral impurities, but it often has a speckled appearance because of the presence of iron.
Fire clay is used in stoneware clay bodies for the purpose of increasing the maturation temperature and to give the object extra roughness.
Kaolin clay is highly pure in its mineral content, and that is why it is used to make porcelain. Most of the times, kaolin clay is light in color. Although they do have some color variations. This clay does not have high plasticity, and therefore, it is not as easy to work with it as compared to other types of clay. Many times, kaolin is mixed with ball clay to increase its workability and decrease the firing temperature.
5. Paper Clay
Paper clay is a great sculpting material. It is a mixture of clay with cellulose fiber, with paper fiber being the most common. It comes with a number of options and opens possibilities that you never thought were possible before.
The addition of paper fiber increases the tensile strength of the clay. If you are familiar with making sculptures, you will know the struggle of wet-to-wet joins and then keeping the thickness of the clay consistent throughout. However, paper clay allows wet-to-wet and wet-to-dry joins. Also, you don’t have to worry about keeping the thickness constant throughout your sculpture. The pieces of the sculpture support themselves and do not collapse. Flat pieces made with paper clay warp less.
Moreover, you can make lightweight sculptures with paper clay. The same sculptures made with any other type of clay will be extremely heavy. The best thing about working with paper clay is that you can always add more details and more elements to your sculpture even after it has dried! Paper clay is surely an incredible type of sculpting clay to play with!
Understanding sculpting techniques is as important as gaining knowledge about the types of sculpting clay. Now that you know more about the various sculpting clays that are available, you can move onto the next section, that is, the sculpting techniques.
There are four basic sculpting techniques that are used to make sculptures. These are:
Carving is a technique that involves chipping away or cutting a shape from a raw mass of wood, stone, or any other material that is hard enough to be made into a sculpture. Carving is a subtractive technique where the material is eliminated from the outside in. Carving makes use of specialized tools that help in scraping away the material to form the final object. The most common carving techniques include:
- Stone carving
- Wood carving
- Ivory carving
- Shell and semi-precious stones carving
Casting is an additive technique where the material, which is usually metal, is melted and poured into a mold. The sculptures are cast from the molten metal that is allowed to cool and harden. One of the most common casting techniques is bronze casting that has been used since ancient times to cast bronze weapons, tools, and sculptures.
Modeling is an additive technique where a soft material that is highly malleable, like clay, is made into a model. The model is built and shaped to create incredibly beautiful and detailed structures. These clay models are then fired at high temperatures, after which they are dried to make their shape permanent. Another type of modeling, other than clay modeling, is wax modeling, where wax is used to make sculptures instead of clay.
Assembling, as you can tell by the name, involves making a sculpture by combining numerous individual materials and objects into one. An example of an assembled sculpture is Martin Puryear’s That Profile.
Sculpting is one of the oldest forms of art. Numerous sculptures have been retrieved that belonged to civilizations that have long since been eradicated from the face of the earth. This indicates that sculpting is as old as mankind. People have been using different sculpting techniques to make tools, weapons, and statues. Today, sculptures are not just a form of art but are also one of the most famous types of visual art displayed in homes, business, and museums.
For anyone who wishes to start a career in sculpting, all they need is the relevant degree, training, and skills to begin. The world of sculpting is massive, with numerous types of sculpting clays and techniques. The market is full of the best types of sculpting clays, including Sculpey, Amaco, Monster Clay, etc. You can use the one that suits your style, meets your requirements, and falls under your budget.
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