Welcome to the fascinating world of creature design and special effects, where the perfect blend of artistry and science brings the impossible to life. In this realm, one of the most crucial ingredients for success is the versatile and ever-evolving medium of clay. With a myriad of types and formulations to choose from, the options may seem overwhelming. In this clay guide, we’ll delve into the four primary types of clay used by industry professionals – polymer clays, water-based clays, oil-based clays, and epoxy clays. Each boasting its unique properties and advantages, these clays are the essential building blocks for crafting awe-inspiring creatures and effects that captivate audiences around the world. So, let’s embark on this journey to discover the distinct characteristics of these clays and unveil the secrets behind their unparalleled versatility.

Polymer Clays

Polymer clay is a versatile, synthetic modeling material used for sculpting, typically made from a mixture of polyvinyl chloride (PVC), plasticizers, and pigments. It is soft and pliable at room temperature, allowing artists and hobbyists to easily shape, mold, and texture it for various projects, including sculptures, jewelry, figurines, and other decorative items.

Unlike natural clay, polymer clay doesn’t dry out, so it can be worked with for extended periods of time without hardening. You can sculpt fine details into it so it’s not only great for maquettes, but for small detailed pieces that are part of a larger sculpt or costume like horns, teeth, spikes, and ornate details.

To permanently set and harden the material, it needs to be baked in an oven, typically at a temperature range of 230-300°F (110-150°C) for a specific amount of time, depending on the brand and thickness of the piece. After baking, polymer clay becomes hard, durable, and retains its shape and color.

Popular brands of polymer clay include Sculpey, Fimo, and Kato Polyclay. These brands offer a wide range of colors, textures, and firmness levels, catering to the preferences and needs of artists and hobbyists alike. My personal favorite is Super Sculpey.

A package of Super Sculpey, a popular polymer clay for sculpting. — Super Sculpey on Amazon

Advantages of Polymer Clays:

Easy to work with: Polymer clay is soft, pliable, and easy to condition, making it suitable for both beginners and experienced artists. You can also get a high level of detail with polymer clays.
Long working time: Unlike natural clay, polymer clay doesn’t dry out when exposed to air, allowing for longer working times without having to worry about the material hardening. This is advantageous for client projects when changes are requested at different stages of development or you need to take your character in a totally different direction. Then, when the project is complete or the character is approved, you can reuse the clay for the next one. Polymer clays are also great for practice, because you can perfect your skills without wasting clay.
Wide range of colors: Polymer clay is available in a vast array of colors, and it can be easily mixed to create custom shades. This eliminates the need for painting after baking. But if you want to paint yours like I frequently do, it takes acrylic paint well.
Low shrinkage: Polymer clay has minimal shrinkage during baking, which helps maintain the integrity of the original design.
Durability: Once baked, polymer clay becomes hard and strong, making it suitable for creating long-lasting sculptures, jewelry, and other items. Polymer clay is also great for strengthening wire armatures. Simply cover your armature in the clay, bake it and now you have a rigid support structure to work with. Soft polymer clay sticks to the baked surface with no problem.
Easy to cure: Polymer clay can be baked in a conventional home oven, eliminating the need for specialized kilns required for natural clay.

Disadvantages of Polymer Clays:

Toxic fumes when burned: Polymer clay is perfectly safe to bake in your home oven so long as you follow the heating and timing instructions. But it can release potentially harmful fumes when overheated or burned, so proper ventilation and temperature monitoring during baking are essential. I always open windows and doors to ventilate the kitchen when baking polymer clay.
Brittle when thin: Although polymer clay is generally strong, it can become brittle and prone to breaking when used in thin or delicate pieces.
Can’t be fired with glazes: Unlike natural clay, polymer clay is not compatible with traditional ceramic glazes, limiting some finishing options.
Not ideal for large sculptures: Polymer clay is better suited for smaller sculptures and projects. For large, more complex sculptures, natural or oil-based clay may be more appropriate due to their increased strength and structural support. Another factor is cost. Polymer clays are a bit more expensive so it becomes cost-prohibitive to make large sculptures with it.
Not air-dry: While some people may consider this an advantage, it can also be a disadvantage for those who prefer a clay that doesn’t require baking to harden.

Water-Based Clays

Water-based clays, also known as wet or natural clays, are a type of sculpting material primarily composed of fine-grained minerals, water, and various organic materials. They are often used in pottery, ceramics, and sculpture because of their versatility, malleability, and ease of use.

When wet, water-based clays are soft and easily manipulated, making them ideal for shaping and forming. As the clay dries, it becomes firm and holds its shape, allowing the artist to refine and add details. Once the sculpture is complete, most of these clays can be fired in a kiln to remove the remaining moisture and harden the clay, resulting in a durable, finished piece.

This is great for sculptures you want to keep permanently. But there are two other important water-based clays used specifically in the creature design industry that serve different functions.

WED Clay

As the name hints at, WED Clay stands for Walter E. Disney and was developed at the Walt Disney Imagineering studio as a tool for artists working on large-scale projects, such as theme park attractions and animatronics. Although it’s a water-based clay, WED clay dries more slowly because its formula includes glycerin which gives it many of the same sculpting qualities of oil-based clay. You can build up forms quickly while the clay has higher water content and then as it dries the surface becomes firmer and easier to carve in finer detail. As you sculpt with WED, it’s helpful to have a spray bottle with water for maintaining moisture and for smoothing. WED clay is primarily used to make pieces for molding and casting such as masks, props, busts, etc rather than the sculpture itself being the end piece. Once you create a mold out of your sculpted piece, the clay is typically thrown out.

Advantages of WED Clay:

Longer working time: WED clay dries more slowly than other water-based clays, allowing artists more time to work on their sculptures before they harden. This extended working time makes it easier to make adjustments and refinements during the sculpting process. It’s important to cover your sculpture in wet paper towels or rags and seal it with a plastic bag to prevent it from drying out between sculpting sessions. But after a while, you may notice some mold growth on your sculpture-in-progress.
Smooth texture: WED clay has a smooth and fine texture that allows for precise details and smooth surfaces in finished sculptures.
Easy to manipulate: WED clay is soft and pliable when moist, making it easy to shape and form into desired structures quickly.
Reduces cracking: The slow drying nature of WED clay reduces the likelihood of cracking as the sculpture dries, which can be a problem with other types of clays.
Easy to smooth and refine: WED clay can be easily smoothed with water or sculpting tools, and it can be carved or sanded after it has dried for further refinements.

Disadvantages of WED Clay:

Limited shelf life: WED clay needs to be stored properly to maintain its moisture content. If not stored correctly, it can dry out and become unusable.
Not suitable for outdoor sculptures: WED clay is not weather-resistant and not suitable for outdoor use, as it can break down when exposed to water or extreme temperatures.
Requires sealing: To protect WED clay sculptures from moisture and to make them more durable, they need to be sealed with a suitable sealant. This is also important to prepare your sculpture for the mold-making process.
Not as strong as other materials: While WED clay is strong when dried, it is not as durable as other sculpting materials like polymer clay or epoxy clay, which makes it less suitable for certain applications.
Not suitable for firing: Unlike traditional ceramic clays, WED clay cannot be fired in a kiln to create a more durable and permanent sculpture. It is best suited for creating prototypes, maquettes, or sculptures that will be cast in other materials.

White Clay

White modeling clay is primarily used as a utility clay for mold-making in the creature design industry and is recommended for making dividing walls for plaster and stone molds. It dries faster than WED clay but some artists also sculpt with it because it’s soft, easy to work with and great for creating details. After the sculpting or mold-making process is complete, the clay is usually fired in a kiln to give it strength and permanence.

Advantages of white clay:

Bright white color: White clay has a high kaolin content, which gives it a bright white color when fired. This makes it an ideal base for colorful glazes and underglazes, as they will appear vibrant and true to their intended hue.
Fine texture: White clay has a smooth, fine texture that allows for intricate detailing and smooth finishes. This makes it a popular choice for creating detailed sculptures, figurines, and pottery pieces.
Versatility: White clay is suitable for a wide range of applications, such as hand-building, wheel-throwing, sculpting, and mold-making. Its plasticity and workability make it an adaptable option for various techniques and projects.
Good glaze fit: White clay typically has a lower shrinkage rate compared to other types of clay, resulting in fewer issues with glaze fit, such as crazing or pinholing.

Disadvantages of white clay:

Lower strength: White clay, particularly earthenware, is generally less strong and durable compared to stoneware or porcelain, making it less suitable for heavy-duty functional ware or pieces that will be exposed to significant wear and tear.
Low thermal shock resistance: White clay, especially earthenware, has a lower resistance to thermal shock compared to stoneware or porcelain, which means it can be more prone to cracking or breaking when exposed to sudden temperature changes.
Slower drying time: Although white clay dries faster than WED clay, its fine particle size can lead to a slower drying time compared to other water-based clays, increasing the risk of warping, cracking, or collapsing if not handled carefully during the drying process.
Firing temperature limitations: While white stoneware can be fired at higher temperatures, white earthenware generally has a lower firing temperature, limiting its strength and durability. Additionally, firing at higher temperatures may cause the clay to become more vitrified and less porous, which can impact its suitability for certain applications.

Oil-Based Clays

Oil-based clay is a type of modeling clay that contains oil as its primary binder. It is also commonly known as “plasticine” or “modeling clay.” This type of clay is preferred by many sculptors because it remains pliable and workable for extended periods of time, making it an ideal medium for sculpting and modeling.

Oil-based clay is made up of a mixture of oils, waxes, and fillers, and it typically does not dry out or harden on its own. This means that sculptures made from oil-based clay are not suitable for permanent display and must be cast in a more permanent material.

One of the major benefits of using oil-based clay for sculpting is that it is very easy to work with. It can be manipulated and shaped with ease, and it does not require any special tools or equipment to get started. It is also non-toxic and does not require firing or baking, making it a safe and convenient choice for sculptors of all skill levels.

There are a few oil-based clays that are among the most popular in the creature design industry and I’ll highlight them below. Some are better for sculpting while others perform best as utility clays for molds and casting.

Chavant NSP

Chavant NSP (Non-Sulfurated Plasteline) clay is a type of oil-based, non-hardening modeling clay that is widely used by artists, sculptors, and professionals in various industries such as animation, special effects, and automotive design. Unlike traditional clay, NSP clay does not contain sulfur, which makes it compatible with silicone rubber molds, a commonly used material in mold-making processes.

Chavant NSP clay is known for its smooth texture, malleability, and its ability to hold fine details, making it a popular choice for creating detailed sculptures and models. It’s available in various hardness levels (soft, medium, and hard) to suit different applications and preferences. The clay can be easily shaped and manipulated at room temperature, and its consistency can be adjusted by heating it under a lamp or dedicated toaster oven on the warm setting. Chavant NSP is also very solvent friendly so the surface can be easily smoothed out using alcohol.

A package of Chavant NSP clay, a popular oil-based clay for sculpting that comes in soft, medium and hard consistencies. — Chavant NSP on Amazon

Advantages of Chavant NSP Clay:

Non-hardening: Chavant NSP clay remains pliable and does not harden over time, allowing for adjustments and modifications to the sculpture or model without a strict deadline.
Sulfur-free: Its sulfur-free composition makes it compatible with silicone rubber molds, which is important for casting and mold-making processes.
Different hardness levels: Chavant NSP is available in various hardness levels (soft, medium, and hard), giving users the flexibility to choose the most suitable consistency for their project.
Holds fine details: The clay is known for its ability to retain intricate details, making it suitable for highly detailed work in sculpting and modeling.
Reusable: Since it doesn’t harden, Chavant NSP can be reused for multiple projects, making it cost-effective.
Easy to manipulate: The clay can be easily shaped and manipulated at room temperature, and its consistency can be adjusted by applying heat or using solvents.

Disadvantages of Chavant NSP Clay:

Not suitable for permanent works: Chavant NSP clay is not suitable for creating permanent sculptures, as it doesn’t harden or cure. Finished works must be cast in another material if they need to be preserved.
Heavy: The clay can be quite heavy, making large sculptures more challenging to work on and transport.
Sensitive to heat: The clay can become too soft or even melt if exposed to high temperatures, which can be a problem during transportation or storage.
Cleanup: Oil-based clays like Chavant NSP can be more difficult to clean up compared to water-based clays, as they don’t dissolve in water. Solvents or special cleaning agents may be required for cleanup.
Cost: Chavant NSP clay can be more expensive than some other types of modeling materials, which may be a consideration for artists or professionals with budget constraints.

Monster Clay

Monster Clay is a professional-grade, sulfur-free, oil-based clay used for sculpting and creating models, maquettes, and prototypes. It is favored by artists, character designers, and special effects professionals due to its properties that make it an ideal choice for both detailed and large-scale projects.

Advantages of Monster Clay:

Reusability: Monster Clay can be reused multiple times, making it an economical choice for artists who frequently work with clay.
Low tack and low stick: The clay is less sticky and tacky than other sculpting materials, which makes it easier to work with and less likely to stick to tools and surfaces.
High plasticity: Its high pliability allows for easy manipulation and smooth blending, making it suitable for creating intricate details and fine textures.
Melting and cooling properties: The clay can be melted at low temperatures and retains its workability as it cools, allowing for a variety of sculpting techniques and tools to be used.
Non-toxic and sulfur-free: Monster Clay is safe to use and compatible with most mold-making materials, reducing the risk of adverse reactions and incompatibilities.

Disadvantages of Monster Clay:

Limited color options: Monster Clay typically comes in only one color (a natural beige). Some artists like to have more color choices to better see details depending on the lighting in their workspace or studio.
Not suitable for outdoor use: Monster Clay is sensitive to heat and may soften or melt when exposed to high temperatures. It’s not recommended for outdoor sculptures or projects exposed to direct sunlight.
Not air-drying or self-hardening: Monster Clay does not harden on its own, so you will need to make a mold and cast your sculpture in a different material if you want a permanent, hard final piece.
Requires heating to soften: You need to heat Monster Clay to make it soft and workable. This can be a minor inconvenience and may require the use of a dedicated oven, toaster oven, crockpot, or heat gun.
Heavy and dense: Monster Clay is a relatively heavy and dense material, which might not be ideal for all projects, particularly those that need to be moved frequently.

Van Aken’s Klean Klay Alternative

Van Aken’s Klean Klay Alternative is a non-toxic, non-drying, non-hardening, and reusable modeling clay designed to be an alternative to the original Klean Klay, which was discontinued in 2014. This alternative clay is used by artists, sculptors, animators, and hobbyists for a wide range of purposes including sculpting and prototyping, but its primary use is for molds and shims as well as metal and cement casting. Because it’s sulfur-free, this clay works great with silicone rubbers and comes in three consistencies: soft, medium, firm. Despite this clay being more intended for utility purposes, some artists do like sculpting with it.

A package of Klean Klay by Van Aken International, a popular oil-based clay for mold-making and casting. — Klean Klay Alternative on Amazon

Advantages of Van Aken’s Klean Klay Alternative:

Non-toxic: The Klean Klay Alternative is non-toxic, making it safe for use by artists and hobbyists of all ages.
Non-drying and non-hardening: The clay doesn’t dry out or harden, allowing users to work on their projects for extended periods without worrying about the material becoming unusable.
Reusable: The clay can be reused multiple times, making it cost-effective and eco-friendly.
Easy to work with: The Klean Klay Alternative has a smooth texture and is easy to manipulate, making it ideal for beginners and professionals alike.
Holds fine details: The clay is capable of capturing fine details, making it suitable for intricate sculptures and models.
Heat-sensitive: The material can be softened with heat, allowing users to easily mold and shape it to their desired form.

Disadvantages of Van Aken’s Klean Klay Alternative:

Not suitable for permanent sculptures: Since the clay doesn’t harden or dry, it is not ideal for creating permanent sculptures or art pieces that need to retain their shape over time.
Sensitive to temperature: The clay’s consistency and workability are affected by temperature changes, which can be a challenge in certain environments or when working on projects that require long periods of time.
Limited color range: Although the Klean Klay Alternative comes in various colors, the range may not be as extensive as other types of clay or modeling materials.
Can be messy: As with any clay or modeling material, working with the Klean Klay Alternative can be messy.
Incompatibility with some finishes: The clay may not be compatible with all types of finishes or sealants, so users may need to experiment with different options to find the best solution for their projects.

Epoxy Clays

Epoxy clay, also known as epoxy putty or epoxy sculpt, is a versatile sculpting material made from a two-part epoxy resin system. It is used by artists, hobbyists, and professionals for a wide range of sculpting applications. The two parts of the epoxy clay, typically a resin and a hardener, are mixed together in equal proportions to create a workable clay-like substance. Once mixed, the epoxy clay hardens over time through a chemical curing process, resulting in a strong, durable, and lightweight sculpture.

Epoxy clay is popular for sculpting because it can be easily shaped and molded, adheres well to various surfaces, and can be sanded, carved, or drilled once cured. Additionally, it is waterproof, resistant to heat, and can be painted or finished with various coatings. Epoxy clay is commonly used for creating jewelry, small sculptures, model making, repairing or modifying existing sculptures, adding strength to wire armatures and various other craft and industrial applications.

I especially like to make nails, teeth and horns with it because you can further sculpt and shape it with a rotary tool once it cures. For sculpting, try brushing the surface with alcohol for less resistance to tooling. The alcohol doesn’t affect the curing process.

Advantages of Epoxy Clays:

Strong and durable: Once cured, epoxy clay forms a hard, solid structure that is resistant to wear and tear, making it ideal for creating long-lasting sculptures and models.
Adhesive properties: Epoxy clay adheres well to various surfaces, including metal, wood, glass, ceramics, and plastics, making it suitable for a wide range of projects.
Waterproof: Epoxy clay is resistant to water, which means it can be used for outdoor sculptures or in environments where moisture is present.
Heat resistant: It can withstand high temperatures, making it suitable for use in applications where heat resistance is essential.
Easy to shape and mold: Epoxy clay can be easily manipulated into desired shapes and forms, making it a versatile sculpting material.
Finishable: Once cured, epoxy clay can be sanded, carved, drilled, and painted, allowing for various finishing options.
No baking or firing required: Unlike some sculpting materials, epoxy clay cures at room temperature, eliminating the need for additional equipment or specialized facilities.

Disadvantages of Epoxy Clays:

Limited working time: Epoxy clay has a relatively short working time, typically ranging from 30 minutes to a few hours, depending on the product. After this time, it becomes less malleable and more difficult to work with.
Potentially toxic: Epoxy clay may contain chemicals that can be harmful if ingested, inhaled, or come into contact with skin. It’s essential to use proper safety precautions, such as gloves and a well-ventilated workspace.
Can be expensive: Epoxy clay can be more expensive than some other sculpting materials, such as polymer clay or water-based clay, which may be a consideration for some users.
Mixing required: Epoxy clay comes in two separate components (resin and hardener) that need to be mixed together in the correct ratio. This can be time-consuming and requires attention to detail to achieve the desired consistency and curing properties.
Not suitable for large-scale sculptures: Due to its weight and cost, epoxy clay may not be the best choice for creating large-scale sculptures.

The world of creature design and special effects is an ever-evolving landscape that thrives on the versatility and innovation of its materials. Polymer, water-based, oil-based, and epoxy clays each possess unique attributes that make them indispensable to the industry. By understanding the intricacies and advantages of these various clays, artists can create stunningly realistic and imaginative creatures that captivate and inspire. As we continue to explore the depths of creativity and push the boundaries of what is possible, it is evident that the right clay can indeed breathe life into the most extraordinary visions. So, go forth and experiment with these remarkable mediums, and let your creations take flight in the magical world of creature design and special effects.

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