How Do You Make Air Dry Clay Less Brittle?

Air dry clay, also known as pottery clay or modeling clay, is a non-hardening clay that dries to a firm, flexible consistency through air exposure. Some of its key properties are that it doesn’t require heat for drying, remains workable even when dry, and is lightweight and easy to sculpt. However, air dry clay also has a reputation for brittleness and fragility, especially in its finished dry state.

Making air dry clay less brittle opens up possibilities for creating sturdier sculptures, detailed models, ceramic decorations, and crafts that require thin extremities or small parts. More durable clay means your creations are less likely to chip, crack, or break during sculpting, drying, and post finishing. The goal is clay that hardens to a strong yet flexible consistency, allowing intricate shaping while minimizing the risk of damage.

Causes of Brittleness

There are a few main reasons that air dry clay can become brittle and prone to cracking:

Lack of plasticizers – Plasticizers are ingredients that increase the clay’s flexibility and workability. Without enough of these, the clay will be stiff and fragile when dry.

Drying too quickly – Fast drying doesn’t allow the moisture in the clay to evaporate slowly and evenly. This causes cracking and brittleness.

Insufficient conditioning – Kneading and working the clay makes the structure more flexible. Not conditioning enough results in a rigid clay that cracks easily.

Adding Plasticizers

One of the most effective ways to make air dry clay less brittle is to add a plasticizer. Plasticizers are materials that increase the clay’s flexibility and workability. Some common household plasticizers you can add include:

• Oils like baby oil or mineral oil – Adding a small amount of oil will help lubricate the clay, making it more flexible. Start with 1 teaspoon of oil per 1 cup of clay.
• Glycerin – Glycerin is a moisture-retaining emollient that helps keep clay soft. Mix in 1-2 teaspoons of glycerin per cup of clay.
• Cornstarch – Cornstarch particles work to absorb moisture and reduce brittleness. Mix in 1-2 tablespoons of cornstarch per cup of clay.

Make sure to thoroughly knead the plasticizer into the clay until well incorporated. Test a small piece to ensure the clay still air dries effectively. Adding too much plasticizer can prevent drying. Find the right balance for your particular clay.

Proper Storage

Properly storing your air dry clay is crucial for maintaining its flexibility and minimizing brittleness. Air dry clay will dry out over time when exposed to air, causing it to become brittle and crack more easily when working with it. To prevent this:

• Keep clay sealed in its original packaging or airtight plastic bags when not in use. Press out any excess air before sealing the bag.
• Store clay in a cool, dry location away from direct sunlight and heat sources. The ideal temperature is around 70°F.
• If storing clay for more than a few months, consider placing the sealed clay bags in a larger airtight plastic bin or tub to protect from humidity.

Following proper storage methods will help keep the moisture content stable in air dry clays. This prevents the clay from drying out prematurely and makes it easier to rehydrate and condition when needed.

Conditioning the Clay

One of the best ways to make air dry clay less brittle is to condition it before use. Kneading the clay briefly with your hands helps warm it up and makes it more pliable. You can also try soaking air dry clay in water for 5-10 minutes before use. This allows the water to penetrate into the clay and soften it. Remove clay from the water and knead again to evenly distribute the moisture. Properly conditioning clay prior to sculpting can help reduce brittleness in the finished piece.

Slow Drying

One of the best ways to prevent air dry clay from becoming brittle is to dry it slowly. Clay that dries too quickly tends to crack and become fragile. Here are some tips for slowing the drying process:

Cover the clay while it’s drying. Drape a damp cloth or paper towel over your clay sculptures or pieces while they dry. This helps trap moisture and prevents the surface from drying out too fast. Make sure the covering doesn’t directly touch the clay.

Dry clay in a humid area. The moisture in the air will slow down the drying time. Try placing your clay pieces in a bathroom while you shower or near a humidifier.

Store clay in an airtight container between uses. Wrap your unused clay tightly in plastic wrap or store it in a zip-top bag or plastic container with an airtight seal. This prevents moisture from evaporating between working sessions.

By controlling the drying conditions, you can keep moisture in the clay longer and minimize brittleness. Always remember that slow drying equals less brittle clay.

Baking

Properly baking air dry clay is important for reducing brittleness. When baked at the right temperature and time, the clay particles fuse together more tightly, creating a stronger and less brittle piece.

Bake air dry clay at temperatures between 130-275°F. Lower temperatures like 130°F will harden the clay without fusing it together completely. Temperatures around 275°F will fully fuse the clay, reducing brittleness and creating a ceramic-like finish.

Bake thinner clay pieces for shorter times, around 15 minutes at 275°F. For thicker pieces, bake longer, from 30-60 minutes. Check frequently to avoid over-baking. The clay should be hard but not burnt or brown at the edges when finished.

Always allow air dry clay pieces to fully dry before baking. Baking wet clay can cause cracking or exploding. Allow 1-3 days of drying time depending on climate, thickness, and drying methods used.

Rehydrating Dry Clay

If your air dry clay has become too brittle from drying out, you may be able to rehydrate it by misting it with water and kneading it to work the moisture back in. This can restore some flexibility and workability.

For very dried out clay, you can also try soaking it in room temperature water for 5-10 minutes. Remove it from the water and knead it on a non-stick surface to evenly distribute the moisture. The clay will absorb water and become malleable again.

Be careful not to over-soak the clay, as too much water can make it sticky. Add water gradually and knead thoroughly until the desired consistency is reached. Let the rehydrated clay rest for a bit before using to allow the moisture to fully absorb.

Alternative Clays

If you find that no matter what you do, your air dry clay continues to be too brittle for your projects, you may want to try using an alternative clay that is less prone to brittleness.

Polymer clay is an excellent option if you want a clay that is flexible and durable when cured. Polymer clay contains plasticizers that make it flexible even when fully hardened. It can be shaped and molded without becoming brittle. Polymer clay needs to be baked at relatively low temperatures to cure it.

Cold porcelain clay is another alternative that is less brittle. It’s made from glue and cornstarch or glue and baby powder. The ingredients bind together to create a smooth, pliable clay that air dries. Cold porcelain doesn’t become brittle as it dries like many air dry clays do. It remains flexible when dry. Cold porcelain clay is also very lightweight.

Trying a polymer clay or cold porcelain clay can allow you to create detailed, intricate pieces that don’t risk breaking or shattering like pieces made from brittle air dry clays. Their composition makes them naturally flexible and durable options.

Tips for Working

When working with air dry clay, there are some helpful tips to keep in mind to avoid brittleness:

Support structure for delicate pieces – If you are making something with thin or delicate appendages like leaves, feathers, or tails, add a wire, toothpick, or other support structure while the clay is still soft. This will reinforce fragile areas and prevent them from drooping or breaking off as the clay dries.

Mix colors for strength – When using colors of air dry clay, mix them together rather than keeping them separate. The clay will dry more uniformly and be less prone to weak spots if the colors are blended.

Smooth gentle handling – Avoid rough handling of the clay that can cause stress points leading to cracking and breakage. Smooth clay gently and avoid pressing too hard or bending pieces repeatedly.