Polymer clay earrings: my adventure as a science student

Polymer clay, unlike normal clay used for ceramics, is made up of building blocks of polyvinyl chloride (PVC), a common form of plastic used in many applications such as healthcare and construction. It is a rigid and strong form of plastic that can withstand high amounts of stress and pressure. To allow the PVC to be flexible enough to be molded into different shapes, a plasticizer is added to PVC to form polymer clay. Colouring is then added to the mixture to give commercial polymer clay the vibrant colors you see in art stores.

However, as polymer clay is technically made from plastics, it can degrade at high temperatures and is not food-safe, especially with some plasticizers that can leech out when in contact with food or liquid. Therefore, unlike natural clay, polymer clay should not be used to make crockery or utensils.

Some common uses of polymer clay include jewelry and electrical insulation since it is lightweight and non-flammable.

The next two pictures show my attempt at making some clay earrings:

As a typical science student, I then wondered about the processes behind the making of these earrings and decided to document them in this blog post.

1. Formulation of designs

Flat designs should be of a minimum of 2mm thick, as thinner earrings will result in brittle products that break easily. This is because after the pieces are baked, they become rigid. Thinner designs would not be able to withstand the force and break easily when an external force is applied.

2. Sculpting the clay

Be careful when handling the clay as you would not want to trap air bubbles within the clay before the baking process. This is because air trapped within the clay mass will expand during baking, forming bumps on the surface of the clay. It can also result in the formation of more brittle products as the air spaces can result in disruption of the structure of the polymers.

3. Baking the clay

Most clay brands have a suggested temperature and duration for the clay to be baked in. I used Sculpey for my mini-project, which suggested 130 deg C for 15 mins. It is not suggested to bake the clay at a higher temperature than suggested, as the PVC will degrade under high temperatures over extended periods of time. In fact, PVC has been shown through multiple studies to break down into polyene (a different compound) even before reaching 250 deg C. The components may also start burning, and inhalation of the fumes can pose dangerous health risks. Some gases released from burnt PVC include carbon monoxide, dioxins, and chlorinated furans. Signs of carbon monoxide poisoning include headache, dizziness, weakness, and eventually can lead to coma and death. Dioxins and furans are known to cause cancer, reproductive, and developmental problems due to their ability to interfere with many essential molecules within the body. Therefore, it is important to ensure adequate air circulation when you are baking your clay!

Don't worry if you find yourself burning your clay! I had a few burnt pieces too. :(

4. Attaching the finishing touches to the earrings:

If you are making new earrings for a friend or yourself, it would be good to start off with hypoallergenic metals for the hooks or studs! Hypoallergenic metals have a lower proportion of nickel in their metal alloy. Nickel is a very common additive to metals used in jewelry as it can help reinforce soft metals such as gold and silver. Metals such as rhodium, platinum, silver, and gold are common hypoallergenic materials recommended for use in earrings. Do check out what is suitable for you and within your price range before you go about getting the materials. Once you have obtained the suitable materials, you can go about putting your earrings together.

After this step, your earrings will be pretty much completed, and you may wear your earrings out!