Why Is My Air Dry Clay Not Drying?

Air dry clay is a popular modeling material composed of water, glue, and natural minerals like clay and gypsum. Unlike traditional clays that require firing in a kiln, air dry clay hardens through evaporation as the water content dissipates over time. While a convenient crafting material for artists and hobbyists, improper drying can turn an exciting project into a frustrating mess. If your air dry clay creations are remaining sticky, soft, or tacky no matter how long they sit, don’t despair. There are several common issues that can prevent air dry clay from properly hardening, most of which can be easily fixed.

Humidity

High humidity is one of the most common reasons air dry clay won’t cure properly. Clay requires evaporation to harden, which is significantly slowed down when moisture levels in the air are too high. Ideal conditions for clay to dry are around 40-60% relative humidity. If humidity levels exceed 70%, it becomes very difficult for the water in clay to evaporate.

Ways to reduce humidity while drying clay include running an air conditioner or dehumidifier, moving the clay to a less humid room, and using a fan to improve air circulation. Avoid drying clay in damp basements, greenhouses, or outdoor sheds. The optimal drying environment is a temperature-controlled indoor room with moderate humidity. Check humidity levels with a hygrometer.

Insufficient Air Flow

Airflow is crucial for allowing clay to dry properly. Air circulation brings fresh, dry air to absorb the moisture from the clay. Without proper airflow, the moist air becomes trapped around the clay, unable to dissipate. This creates a humid microenvironment that inhibits the clay from drying.

Clay needs continuous air circulation to promote drying. Try to avoid enclosing clay in tight spaces like plastic bags or containers where airflow is restricted. If storing clay projects, use open shelves or drying racks. Position pieces so air can flow over the surface and around all sides. Use fans or open windows to keep fresh air moving, especially in humid climates. The more freely air can circulate around clay, the faster moisture can evaporate.

Increasing airflow is one of the easiest and most effective ways to troubleshoot clay drying issues. Simple adjustments like spacing pieces further apart, keeping the clay work area open, and using fans can significantly improve drying time. Proper air circulation brings the dry, moving air that clay requires for moisture to dissipate.

Stored Improperly

If clay is sealed tightly or touching other surfaces, it can’t dry properly. Air circulation is critical for allowing moisture to evaporate from the clay. Follow these guidelines for proper clay storage:

• Store clay in an airtight container or plastic bag, sealing loosely or with air holes poked in the top. Do not tightly seal clay in an airtight environment.
• Store clay rolls vertically in a container, not laying flat or piled on top of each other. This allows air flow all around the clay.
• After use, wrap clay in plastic wrap or foil, again avoiding an airtight seal. Poke a few holes for ventilation.
• Do not pack clay into a solid block or slab. Leave spaces for air circulation.
• Store clay in a cool, dry area away from extreme temperature and humidity changes.

Following proper open air storage methods will help moisture evaporate from the clay over time for successful drying and curing.

Too Thick

One of the most common reasons air dry clay does not dry properly is that it was sculpted too thick. Thicker pieces take longer for the moisture to fully evaporate from the center.

For best results, aim to keep air dry clay projects under 1/4 inch (0.5 cm) thickness. Going above 1/2 inch (1 cm) will dramatically increase the drying time needed. If your creation is large or has bulky parts, consider using foil, cardboard, or other materials as an internal support structure. This allows you to keep the outer clay layers thinner.

Check the packaging or manufacturer recommendations for the maximum suggested thickness when working with a particular brand of air dry clay. In general, it’s advisable to aim for thinner layers whenever possible to ensure quick and effective drying.

Cold Temperature

Cooler temperatures slow the drying of air dry clay. This is because the evaporation process depends on the clay being warm enough for the moisture to convert from a liquid to a gas and be released. At colder temperatures, this evaporation happens much more slowly.

For best results, air dry clay should be dried at room temperature or slightly warmer, between 70-80°F. Temperatures lower than 60°F can dramatically increase drying times. Try moving your clay drying to the warmest room in your home or use a space heater to maintain the ideal temperature range. Just be careful not to have the clay too close to the heat source as extremes can cause cracking.

Additives

Some additives like oil or wax can inhibit the drying process of air dry clay. These lubricants get mixed into the clay and prevent water from evaporating properly. Using too much of an additive like glycerin or cornstarch will also hinder drying. The more additives added, the longer the clay will take to cure.

It’s best to avoid adding anything extra to air dry clay that isn’t required. Stick to minimal liquid clay softeners only if needed. Adding paint, glitter, or food can introduce moisture and oils that stop the clay from hardening. Resist the urge to mix in additives and stick to plain air dry clay whenever possible.

Clay Composition

Some clays naturally dry slower than others due to their composition. Air dry clay is made from a mix of ingredients that affect the drying time.

The main ingredients in air dry clay are:

• Water – This acts as a binding agent but also slows down drying.
• Flour or starch – This also binds the ingredients but absorbs moisture which helps drying.
• Salt – Added for texture. Doesn’t affect drying time.
• Oil – Helps make the clay more workable. Slows down drying.
• Acrylic polymer – Binds ingredients and makes the clay elastic. Can slow drying.
• Plaster – Absorbs moisture and speeds up drying.

Clays with more water, oil or acrylic polymer will dry slower. Clays with more plaster or starch will dry faster. Check the clay ingredients and ratios if it is drying unusually slowly.

Troubleshooting

If you are finding your air dry clay is not drying properly, there are some key troubleshooting steps you can take:

• Reduce humidity – Try drying the clay in a less humid environment or use a dehumidifier.

• Improve air flow – Ensure the clay is in an area with good airflow and is not tightly enclosed.

• Store properly – When not drying, store clay in an airtight container in a cool, dry area.

• Reduce thickness – Sculpt thinner sections that will dry faster.

• Raise temperature – Try drying clay in a slightly warmer area.

• Avoid additives – Things like glitter, paper, and pasta lengthen drying time.

• Check composition – Polymer clays take longer to dry than cellulose-based clays.

Following these troubleshooting tips should help identify and resolve any drying issues with air dry clay.

Conclusion

In summary, there are several common reasons why air dry clay may not be drying properly:

• High humidity prevents the clay from drying out.
• Lack of air circulation means moisture cannot escape.
• Storing clay in an airtight container traps moisture inside.
• Thick pieces take longer to dry throughout.
• Cool temperatures slow the drying process.
• Additives like oils or silicone make drying difficult.
• Poor quality clay has less binding agent to solidify.

To help your air dry clay dry faster and more effectively:

• Work in a dry environment without excess moisture in the air.
• Allow plenty of airflow around your clay pieces.
• Store clay properly when not in use.
• Keep pieces thin to quicken drying time.
• Work in a warm area.
• Avoid additives that inhibit drying.
• Use high quality air dry clay.

Following these tips will help ensure your air dry clay cures properly and your projects can be completed on schedule.