How Do You Keep Clay From Hardening?

Exposure to air causes clay to dry out and harden over time, which can be inconvenient when working with certain clay projects. Keeping clay soft allows you to take your time so the material doesn’t harden before you finish sculpting pottery, making clay figures, or doing crafts with kids.

If you notice your clay drying out and becoming difficult to manipulate, there are several effective techniques to rehydrate and soften it so you can continue working without having to buy more.

Store in an Airtight Container

Air exposure is one of the main causes of clay drying out and hardening over time. Preventing air from coming into contact with
your clay is an effective way to prevent it from hardening prematurely.

Try storing your unused clay in an airtight container. A container that fully seals and prevents air circulation will help keep the moisture
in your clay so it stays soft and pliable. Some airtight options to consider:

• Plastic wrap tightly secured over a clay ball or textured work surface
• Resealable ziplock bags
• Plastic containers with tight fitting lids

An airtight container should keep the moisture in and minimize air exposure to keep your clay in a workable state. Choose a storage method
that works well for your project size and check on your clay periodically. Reseal or add moisture as needed to maintain the consistency you
want.

Use a Clay Softener

One of the most effective ways to keep clay malleable is by adding a clay softener or plasticizer. These additives can greatly increase the amount of time clay stays workable by helping it retain moisture and flexibility.

Some common household clay softeners include:

• Glycerin – a few drops of glycerin will make clay more elastic and prevent it from hardening too quickly.
• Vinegar – acetic acid in vinegar reacts with clay to extend its working time. Use a few teaspoons per pound of clay.
• Lemon juice – the citric acid in lemon juice penetrates the clay, allowing it to stay pliable for longer periods out of its packaging.

Testing which softener works best with the specific type of clay can help determine the ideal ratio to use for retaining ideal texture and pliability. As a general rule, start with small amounts of softener at a time. Too much can make clay sticky or prevent it from ever fully hardening.

Keep the Clay Cool

Exposing clay to excess heat sources like direct sunlight or heaters can cause it to dry out more quickly. As the clay loses moisture due to evaporation, the clay hardens. To slow down this process, aim to keep your clay in a cool environment.

Storing the clay in the refrigerator is an excellent option, as the cool constant temperature will significantly slow the drying process. Wrap your clay tightly in plastic wrap or place it in an airtight plastic container before refrigerating. This prevents the clay from absorbing food odors. Most polymer and oil-based clays can be stored this way for months.

Avoid storing clays long-term in temperatures below freezing, as some water-based clays can become permanently hard in extreme cold. Follow storage recommendations on your clay’s packaging or aim for a temperature between 60°-75°F.

Rehydrate Dried Clay

If your clay has started to dry out and harden slightly, there are a couple methods you can try to rehydrate it. The key is catching the clay before it has completely air dried and hardened.

For clay that is still somewhat workable but drying, misting the surface with water and wrapping it tightly in plastic wrap or placing it in a sealed plastic bag can draw moisture back to the surface and soften it again. Allow it to sit for a few hours or preferably overnight.

However, if the clay has completely hardened and is not pliable at all, rehydration will not be possible. At that point, the clay’s chemical composition has changed and absorbed all the moisture it can take in. Soaking or misting fully hardened clay will not make it usable again.

Avoid Exposure to Air

Exposing clay to air during the sculpting process causes it to dry out prematurely. As clay loses moisture, it starts to harden. This makes the clay more difficult to manipulate and can lead to cracks forming. Limiting air exposure is important to maintaining a smooth, malleable clay consistency for sculpting.

When taking a break from sculpting, make sure to cover unfinished clay pieces with plastic wrap or a damp cloth. This creates a protective barrier against air. Keeping your hands and tools wet while working can also prevent them from pulling moisture out of the clay. Try keeping a damp sponge nearby to frequently moisten hands and smooth clay surfaces.

Working quickly and minimally exposing clay during the sculpting process helps the clay retain moisture for maximum workability. Along with covering or wrapping clay between work sessions, limiting overall air exposure will prevent premature drying or hardening.

Use a Clay with Longer Working Time

One way to keep clay from hardening prematurely is to use a clay that has a naturally longer working time. This will give you more flexibility while you are sculpting or modeling without having to constantly rehydrate the clay.

For example, polymer clay is made with plasticizers that keep it soft and malleable for an extended time. Most polymer clays can be stored for months or even years without drying out. Popular brands like Sculpey and Fimo claim to offer several hours up to weeks of working time depending on the type.

Similarly, oil or wax-based clays like Roma Plastilina are formulated with ingredients that keep them workable for longer. The oils and waxes prevent the clay from drying out quickly. These types of clay may stay soft and flexible for many hours or days depending on the environment and how they are stored between uses.

Choosing the right type of clay with an inherently longer open working time can save you the hassle of having to continuously rehydrate and condition drying clay.

Add a Retarder

Another way to prevent clay from hardening prematurely is to add a retarder. Retarders are chemicals that inhibit the drying process of clay by slowing the evaporation of water and breaking down clay’s bonds.

Common clay retarders include:

• Glycerin — Just a few drops of glycerin per 1 lb of clay slows down drying time.
• Vinegar — Mix in 1 teaspoon of white vinegar per 1 lb of clay to delay hardening. Vinegar reacts with the clay to slow hardening.
• Liquid starch — Adding 1-2 teaspoons of liquid starch per 1 lb clay keeps your sculpture workable for longer.

Test any retarders on a small piece of clay first to ensure they provide enough working time without making the clay too sticky or soft.

Consider an Air Dry Clay Alternative

Instead of traditional clays like baking clay or ceramic clay, consider using an air dry clay. Air dry clays like polymer clay and cold porcelain clay don’t actually harden through air exposure. They remain soft and malleable, so you can continue working on projects indefinitely and reuse leftovers.

For original sculptures, jewelry pieces, and clay projects you want to repurpose or reshape later, an air dry clay is ideal. Materials like polymer clay will stay pliable and workable for multiple projects for many years. Since they don’t dry out, you can save unused portions and used pieces to form new creations without worrying about hardening or buying more clay.

Conclusion

Keeping clay from hardening requires following a few strategies to limit exposure to air, which causes hardening. Store clay in an airtight container to prevent air exposure and keep moisture in. The use of clay softeners or additives and refrigeration can also maintain the pliability of clay. For clay that has dried out, soaking it in water can often rehydrate it. Another option is to switch to an air dry clay formula that does not require moisture and does not harden when exposed to air.

Certain methods like using a sealable container or refrigeration help keep clay moist and malleable by limiting air exposure and evaporation. If clay does start to dry out, rehydrating or a clay softener can restore some pliability. Planning ahead to use clays with longer working times gives more opportunity to work on clay sculptures or projects before hardening happens. Finally, bypassing the issue entirely with specialized air dry clays means you can take your time with less worry over moisture loss and hardening issues.