Clay is an extremely versatile artistic medium used by potters, sculptors, and craftspeople worldwide. However, one of the challenges of working with clay is preventing it from drying out and becoming unusable. Learning proper clay storage techniques is essential for keeping your clay in ideal working condition.
In this comprehensive guide, we will cover everything you need to know about storing clay correctly. We’ll discuss the reasons clay dries out, explain the different types of clays and their specific storage needs, and provide tips for optimal clay storage. Whether you’re an experienced ceramicist or just starting out working with clay, this article will help you master clay storage and keep your clay usable for as long as possible.
Why Does Clay Dry Out?
Before we get into the specifics of storage, it’s important to understand why clay dries out in the first place. There are two main reasons:
Evaporation
Clay contains water. Over time, the water molecules in the clay evaporate into the air, causing the clay to dry out. Without the right storage, this evaporation process happens faster. Keeping clay properly sealed prevents rapid water evaporation.
Absorbtion
Clay will also absorb water from the air and surrounding environment. If the humidity is low, the clay will pull moisture from the air more quickly, resulting in faster drying. Storing clay in a humid environment helps prevent excessive moisture absorption and drying.
So in summary, clay dries out due to losing water content either through evaporation or absorption. Our goal with proper storage is to slow down these processes as much as possible.
Different Types of Clays and Their Storage Needs
There are several major types of clays used in pottery and ceramics. Each has unique properties that impact how it should be stored. Let’s go over the main types:
Earthenware Clay
Earthenware clays are low-fire clays that mature at lower kiln temperatures, typically below 2,200°F. They are porous and absorbent. Common examples include terracotta and red clay.
Because earthenware clays are so absorbent, they can dry out rapidly. Keeping them sealed in plastic to retain moisture is important.
Stoneware Clay
Stoneware clays are mid-range firing clays, maturing between 2,200°F to 2,300°F. They are less porous than earthenware clays but still somewhat absorbent. They also dry relatively quickly compared to other clays.
Stoneware clays benefit from sealing in plastic to maintain moisture levels. Allowing them to air dry excessively will result in cracking and unusable clay.
Porcelain
Porcelain clays are high-fire clays, maturing above 2,300°F. Of all pottery clays, they are the least porous and absorbent. However, they still require proper storage to prevent drying.
Although they won’t dry out as quickly as earthenware or stoneware, keeping porcelain clays sealed is recommended. Leaving porcelain clay exposed consistently will eventually cause drying.
Polymer Clay
Polymer clays are a type of modeling clay based on PVC resin. Since they contain no water, they do not actually dry out in the same way as traditional clays. However, polymer clays can become hard and less malleable over time.
Keeping polymer clay sealed helps prevent exposure to air, which can cause the clay to cure and harden prematurely. Storing different polymer clay colors separately is also recommended, as pigments may bleed.
In summary, know the specific clay type you are working with and its properties to determine the optimal storage needs. Quick-drying earthenware and stoneware clays especially need sealing, while polymer clays require protection from air exposure. Tailor your storage methods accordingly.
Tips for Storing Clay
Now let’s get into the best practices for storing your clay. Follow these tips for keeping clay in its optimal smooth, flexible, workable state:
Wrap in Plastic
The number one storage recommendation is to keep clay wrapped in plastic at all times. This prevents air exposure and moisture loss. Plastic wrapping inhibits evaporation and absorption, the two causes of clay drying out.
You can use plastic wrap, plastic bags, or airtight plastic containers to seal clay. Make sure clay is entirely enclosed by the plastic on all surfaces. Remove clay from plastic wrapping only when you are ready to use it.
Use a Clay Keeper
For large blocks of clay, a specialized tool called a “clay keeper” is useful. Clay keepers are two-piece plastic containers designed to hold clay blocks with an airtight seal.
They have a top and bottom that clasp together tightly, protecting the clay inside. Clay keepers come in sizes suited for different clay brick dimensions. They make keeping large amounts of clay sealed incredibly easy.
Store in a Cool, Dark Place
Choose a storage location that is cool, dark, and relatively humidity-controlled. Avoid hot spots or areas with extreme temperature fluctuations. Do not store clay in direct sunlight, which can heat and dry the clay.
Ideal locations are basements, cabinets, and pantries. Air conditioned environments are best if possible. Keeping clay under stable comfortable temperatures maximizes usable shelf life.
Use Water-Based Clay
Some clays are sold in a wet, water-based state. These maintain high moisture content and are very resistant to drying out. However, they are heavier and only suitable for certain projects.
Water-based clays are excellent choices for storage since they cure very slowly. The water keeps them malleable even after long periods sealed in plastic.
Consider Oil-Based Clays
Oil-based clays are another option that resist drying. Primaclay and other oil-based clays contain mineral oil instead of water. The oil allows the clay to remain flexible when stored.
Oil-based clays last significantly longer than normal clays. If you don’t plan on using the clay soon, an oil-based type may be ideal for your needs. The oil prevents hardening and crackling over many months of storage.
Add Moisture
If your clay does start to dry up, you may be able to recondition it by adding moisture back. Mist the clay lightly with water and knead it in, which will soften and improve flexibility.
However, re-wetting clay can lead to bacterial growth if water gets trapped in the center. Only add small amounts of moisture to the outer surface if needed. Storing correctly from the start is best to avoid overly dried clay.
In summary, keep clay sealed airtight, store in a stable environment, and use naturally moist clay types for best results. With proper methods, your clay can stay fresh for many months.
How to Store Unused Clay
Handling leftover clay after projects requires some specific steps. Here is how to properly store unused clay:
Knead Well
The first step with any leftover clay is to knead it thoroughly. This redistributes moisture evenly throughout the clay. Dense areas or dry spots get remedied through kneading.
Next, form the clay into a smooth ball or brick shape. This minimizes trapped air pockets. A uniform shape allows moisture to disperse evenly through the stored clay.
Estimate Needed Amount
Try to only keep as much unused clay as you will realistically need for upcoming projects. Excess clay takes more space and is more challenging to keep in ideal condition.
Think about your clay usage rate and upcoming plans. For example, if you complete a project weekly, just save enough for 1-2 weeks maximum. Limit excess amounts sitting idle.
Seal in an Airtight Bag
Place the kneaded clay in a heavy-duty plastic bag, squeezing out excess air. Seal the bag completely airtight. This prevents moisture loss through air exposure.
You can also use plastic wrap or a clay keeper for an airtight seal. The key is preventing air circulation to unused clay for storage.
Store Flat
Keep stored clay bricks or balls flat in a single layer, rather than stacking multiples. This maintains a consistent thickness, allowing moisture to evenly permeate the clay.
If clay is stacked unevenly, the bottom sections may harden and dry faster than the top. Storing flat prevents moisture concentration imbalances.
Follow these steps each time you have leftover clay from a project. With proper kneading, sealing, and storage of unused portions, your clay will stay fresh and ready for later use.
Ideal Clay Storage Conditions
To summarize, here are the optimal temperature, humidity, and other conditions for clay storage:
– Temperature: 65-75°F is ideal; avoid extremes or fluctuations
– Humidity: 40-60% humidity prevents excessive drying
– Darkness: No direct light which heats and dries clay faster
– Air exposure: Completely seal clay from air circulation
– Location: Cool basements or closets work well
– Position: Store clay flat in a single layer, not stacked
– Clay type: Use moist clay and water-based varieties
Maintaining these ambient conditions and following the other steps outlined will keep your clay in the perfect malleable, flexible state for whenever you need it. Monitor conditions and adjust as needed in your storage space.
Signs Your Clay is Drying Out
With less-than-ideal storage conditions, clay can start to dry out over time. Here are some telltale signs that your clay is losing too much moisture:
– Cracking or flaking on the surface
– Clay feels hard or stiff instead of soft
– Clay becomes brittle and crumbly
– Loss of pliability when kneading
– Reduced ability to roll, bend, or shape the clay
– Powdery residue left on hands after touching
– Difficulty reconditioning by adding moisture
– Lower weight as moisture content is lost
If you notice any combination of these warning signs, your clay has become too dry. You’ll need to try rehumidifying the clay or use it soon before it becomes completely unusable.
Catching moisture issues early allows you to improve storage and potentially restore flexibility. Letting clay dry out too severely can permanently harden it into a solid lump.
Reviving Dried Clay
If your clay does dry out, don’t panic. Depending on the severity, you may be able to bring it back to a usable state. Here are some methods to rehydrate overly dried clay:
Mist with Water
Misting the outer surface with water and kneading it in reintroduces moisture to stiffened clay. Do this sparingly, as over-wetting can cause problems. Only use tiny amounts of water as needed.
Seal in Plastic Bags
Wrapping hardened clay in plastic bags traps any remaining moisture. Let it rest sealed for several days so the clay reabsorbs the available humidity.
Use a Clay Humidifier
You can buy specialty humidifiers made for restoring dried clay. These sealed containers have sponges for soaking up water and creating a moist environment for dried clay chunks to rehydrate in.
Soak in Vinegar
For extremely dried clay, soak chunks in vinegar for 1-2 days. The vinegar pulls moisture into the clay. Baking soda afterwards neutralizes any smell. This severe rehydration method can restore badly hardened clay.
With some TLC and the right techniques, you can often renew dried clay to a usable state again. Work quickly once you spot signs of drying before it becomes irreversible.
Conclusion
Properly storing clay requires just a few simple procedures that make all the difference. By keeping your clay sealed from air, controlling humidity, using optimal clay types, and monitoring for drying, you can extend the life of your clay indefinitely.
Remember to knead reused clay thoroughly, limit excess amounts stored, and check regularly for drying signs like cracking. With practice, clay storage becomes second nature. Your clay will stay smooth, flexible, and ready for every creative project with these techniques.
