What Is The Difference Between Polymer Clay And Air Dry Clay For Earrings?

Polymer clay and air dry clay are two of the most popular types of clays used for making earrings and other jewelry or crafts. While they share some similarities, they have distinct differences in their composition and properties that affect the user experience and final results. Polymer clay is a modeling material that must be baked in an oven to cure, while air dry clay will harden naturally at room temperature. Understanding the unique characteristics of each clay type allows crafters to select the optimal material for their needs and desired outcomes.

Composition

Polymer clay is made from polymers such as polyvinyl chloride (PVC) along with plasticizers and colors. The polymers provide structure while the plasticizers make the clay malleable.

In contrast, air dry clay is made from natural materials like cellulose fibers from wood pulp. It also contains binders like glue and hardeners like borax. The cellulose provides structure while the glue allows the clay to be molded.

Drying/Curing Method

The main difference between polymer clay and air dry clay lies in how they harden and cure.

Polymer clay contains chemicals called “plasticizers” that remain malleable at room temperature. Polymer clay cures through heating in the oven at around 265°F–275°F for 10–25 minutes. The heat activates the binding agents and plasticizers in the clay, causing the material to undergo chemical changes that permanently harden it. Polymer clay will remain pliable and reusable until baked.

In contrast, air dry clay hardens through simple water evaporation. As the water evaporates over the course of 1-7 days, the clay particles fuse together and the clay becomes rigid. Since no heat is required, air dry clay will begin hardening immediately after it is exposed to air and shaped.

In summary, polymer clay requires heat to cure while air dry clay cures naturally at room temperature through drying.

Shrinkage

Polymer clay experiences very little shrinkage, usually around 1% or less from the original sculpted size. This is because polymer chains within the clay link together without reducing volume as the clay cures. The lack of shrinkage makes polymer clay excellent for achieving precision and detail in pieces.

In contrast, air dry clays can shrink considerably during the drying process, from 15-30% on average. As the water evaporates from the clay, the material shrinks and reduces in size. Pieces made with air dry clay need to account for the shrinkage factor when aiming for an exact finished size and shape.

Flexibility

Polymer clay is very flexible, making it an ideal material for delicate jewelry like earrings. Even when cured, polymer clay remains pliable and elastic. This allows earring designs to bend and flex without breaking. Polymer clay can be conditioned to increase its flexibility, allowing it to be molded into intricate shapes. The softness and pliability of polymer clay also makes it comfortable to wear in earrings, as it molds to the shape of the ear.

Air dry clay is much more brittle and prone to cracking when flexed, especially as it dries. This makes it a poor choice for earrings, which undergo a lot of subtle bending and movement when worn. Earrings made from air dry clay can snap if bent too far. The inflexibility of air dry clay limits the complexity of earring designs, as delicate shapes are likely to break. The hardness of cured air dry clay can also make earrings uncomfortable to wear long-term. So for earrings that need to flex and move with the wearer, polymer clay is vastly superior in flexibility compared to air dry clay.

Texture

Polymer clay has a very smooth, soft, and malleable texture before baking. It can be conditioned to become extremely soft and smooth. The finished texture after baking can range from smooth/glossy to a matte finish depending on the brand and finish. Polymer clay maintains a smooth, non-porous surface after baking. The texture can be easily altered by rolling texture sheets over the clay.

Air dry clay starts out quite smooth and malleable before drying but tends to harden and become more difficult to smooth out as it dries. It develops a gritty, porous surface as it dries. The finished texture of air dry clay is rougher and more grainy than polymer clay unless it is carefully sanded and polished after fully drying. Air dry clay also tends to show fingerprints and imperfections more than polymer clay. Overall, polymer clay is better for achieving smooth surfaces and fine detail, while air dry clay has a more organic, homemade texture.

Weight

When making earrings, weight is an important consideration. Heavier earrings can stretch earlobes over time and become uncomfortable to wear for long periods. Lighter earrings are usually preferable.

Polymer clay is generally lighter than air dry clay. Polymer clay contains plasticizers which make it lightweight and flexible. A typical pair of polymer clay earrings weighs 1-5 grams.

Air dry clay contains more natural ingredients like cellulose or clay minerals. This gives it a heavier and denser texture. A comparable pair of air dry clay earrings can weigh 5-15 grams. The exact weight depends on the thickness and size of the earrings.

So polymer clay is lighter and better suited for making lightweight pairs of earrings that won’t stretch earlobes. Air dry clay works for smaller and thinner earring designs, but larger or dangly earrings may become too heavy over time.

Durability

When it comes to durability, polymer clay has a clear advantage over air dry clay. Once polymer clay is cured, either in a dedicated oven or regular kitchen oven, it undergoes a chemical process that hardens and strengthens it. The end result is a durable plastic material that will not become brittle or degrade over time. Properly cured polymer clay can last for many years without showing signs of wear or deterioration.

In contrast, air dry clay simply dries out through water evaporation. While it becomes hard, air dry clay remains porous and prone to chipping, cracking or breaking with rough handling. If exposed to moisture, air dry clay can soften or even partly dissolve. Pieces made with air dry clay must be carefully handled and protected from moisture to preserve them. For jewelry and other wearable items that will be subjected to regular use and contact with skin, polymer clay is a much more durable and long-lasting choice.

Ease of Use

Polymer clay is very easy to work with. It is soft and pliable straight out of the package and does not require any special preparation. Polymer clay can be easily shaped by hand and holds fine details well. It also retains its elasticity, allowing it to be stretched, twisted, and sculpted without cracking. Polymer clay’s texture makes it easy to blend and smooth colors together. It does not stick to hands, work surfaces, or tools, so working with it is generally mess-free.

Air dry clay starts out soft, but stiffens quickly as it dries. Working time is limited before the clay becomes too firm to manipulate. It can also become sticky as it dries, making sculpting tricky. Air dry clay is best used in thin layers and simple shapes, as the clay can crack if overworked. Smoothly blending colors and achieving fine details take practice with air dry clay. Proper conditioning and keeping tools/hands wet during use can improve workability, but does not provide the same ease of use as polymer clay.

Summary

Both polymer clay and air dry clay can be used to create earrings, but they have some notable differences. Polymer clay does not shrink, is more flexible when cured, and results in lightweight earrings. However, it requires baking to cure. Air dry clay is easier to work with since it dries at room temperature, but produces heavier earrings that are more prone to cracking over time. For beginners or simple earring designs, air dry clay may be preferred for its simplicity. Polymer clay allows for more intricate and durable earrings, but requires more skill. Overall, the type of clay used depends on factors like desired durability, weight, texture, complexity of the design, and personal preference. Both clays have their advantages and work well for handmade earrings.