Why is my polymer clay shiny after baking?

Polymer clay is a versatile and popular medium used by artists, crafters, and hobbyists to create a wide range of creative projects. One common phenomenon that may puzzle beginners is the shiny appearance of polymer clay after it has been baked. In this article, we will explore the reasons behind this glossy finish and provide insights into achieving the desired results for your polymer clay creations.

The Baking Process

Polymer clay is composed of tiny particles of PVC, plasticizers, and pigments. When it is heated during the baking process, the plasticizers soften and the particles fuse together, resulting in a solid and durable object. The baking temperature and time can vary based on the brand and type of polymer clay you are using.

The Shiny Finish

There are a few reasons why your polymer clay may have a shiny finish after baking:

1. Polymerization and Smoothing:

During baking, the plasticizers in the polymer clay are activated, causing the particles to bond and harden. This process, known as polymerization, can result in a smooth and glossy surface. The heat and pressure within the oven may also contribute to smoothing out imperfections, enhancing the shine.

2. Liquid Plasticizers:

Some polymer clays contain liquid plasticizers that can migrate to the surface during baking. As the clay cures, these plasticizers may rise to the top, creating a shiny appearance. This effect can be more pronounced in certain clay brands and formulations.

3. Conditioning and Compression:

Properly conditioned polymer clay is more likely to have a shiny finish. Conditioning involves kneading and manipulating the clay to make it pliable and uniform in texture. Additionally, compressing the clay during sculpting or shaping can contribute to a smoother and shinier surface.

Achieving Different Finishes

If you prefer a matte or less shiny finish for your polymer clay creations, there are several techniques you can explore:

  • Sanding: Gently sanding the surface of your baked polymer clay with fine-grit sandpaper can reduce shine and create a softer appearance.
  • Buffing: Buffing the clay with a soft cloth or a polishing tool can help to achieve a satin or matte finish.
  • Applying Matte Varnish: After baking, you can apply a matte varnish to the surface of your polymer clay to reduce shine and create the desired finish.


The shiny finish that polymer clay often develops after baking is a result of the polymerization process and the plasticizers within the clay. While this glossiness can enhance the appearance of your creations, it may not always be the desired effect. By understanding the factors that contribute to the shine and exploring various finishing techniques, you can achieve the perfect look for your polymer clay projects, whether it’s glossy, matte, or anything in between.

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