Does polymer clay fully harden?

Polymer clay is a versatile and popular crafting material used by artists, hobbyists, and DIY enthusiasts to create a wide range of items, from jewelry and figurines to home decor and sculptures. One common question that often arises among those new to working with polymer clay is whether it fully hardens after baking. In this article, we’ll explore the characteristics of polymer clay and delve into the process of curing to better understand its hardening capabilities.

Understanding Polymer Clay

Polymer clay is a type of modeling clay that is primarily composed of PVC (polyvinyl chloride) particles and a liquid plasticizer. This unique composition allows it to remain pliable and malleable until it is exposed to heat. Polymer clay comes in a variety of colors and brands, each with its own characteristics and qualities.

The Curing Process

To achieve its desired hardness and durability, polymer clay must undergo a curing process. Curing is the term used to describe the process of baking polymer clay in an oven at a specific temperature and time. During the baking process, the heat causes the PVC particles to undergo a chemical reaction, known as polymerization. This reaction leads to the fusion of the particles, resulting in a solid and hard material.

It’s important to note that the curing temperature and time can vary depending on the brand and type of polymer clay being used. Generally, polymer clay is baked at temperatures between 265°F (130°C) and 275°F (135°C) for about 15-30 minutes per 1/4 inch (6mm) of thickness. Failure to follow the recommended curing guidelines may result in under-cured or over-cured clay, affecting its final hardness and appearance.

Full Hardening and Strength

When polymer clay is properly cured, it can achieve a high level of hardness and durability, making it suitable for a wide range of applications. Fully cured polymer clay items can be sanded, drilled, carved, and polished without losing their shape or integrity. This makes it a popular choice for creating intricate details and delicate designs.

However, it’s important to keep in mind that while polymer clay can become quite hard, it is not as strong as some other materials like ceramics or metals. Thin and delicate pieces may still be somewhat flexible or prone to breakage if subjected to excessive force or pressure.

Additional Factors

Several factors can influence the final hardness of polymer clay:

  • Brand and Type: Different brands and types of polymer clay may have varying levels of hardness after curing.
  • Thickness: Thicker pieces of clay may require longer curing times to ensure full hardening.
  • Curing Temperature: Incorrect temperatures can lead to inadequate curing, affecting the hardness of the clay.
  • Cooling Period: Allowing the clay to cool completely after baking can contribute to its overall hardness.


Polymer clay is a versatile and fascinating medium that can be transformed into stunning creations through careful molding, shaping, and curing. When properly baked and cured according to manufacturer guidelines, polymer clay can achieve a high level of hardness, making it suitable for a wide array of artistic projects. While it may not be as strong as some other materials, its unique qualities and range of vibrant colors continue to make it a popular choice among artists and crafters alike.

So, if you’re looking to dive into the world of polymer clay crafting, rest assured that with the right techniques and attention to detail, you can create beautiful, durable, and long-lasting pieces that showcase your artistic vision.

Rate article
Add a comment