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How to Harden Non-Hardening Clay

how to harden non-hardening clay

When people think about clay, they usually think of the kind that hardens when baked in an oven. But there’s a type of clay too that doesn’t harden with heat- it needs to be hardened by other methods. So how do you go about hardening nonhardening clay?

Before jumping right to a solution on how to harden non-hardening clay, it’s important to know what type of clay you have. Different types require different methods for baking and drying so make sure that the process is right for your specific kind. The four types of modeling clays are ceramic clays, oil-based clays, watercolor clay, and polymer-based.

Polymer is the most commonly used type of clay for crafting; while it’s a little more difficult to work with at first than other types, this type hardens when baked in an oven. Putting polymer clay in the freezer before baking it will make it more pliable. Below we have covered the basics you need to know on how to harden the clays with or without an oven.

How To Harden Non-hardening Modeling Clay Using An Oven

Step 1: Read the package instructions

Before putting the clay in the oven, make sure to read the instructions because different types or colors of clays may have different baking temperatures. If you can’t find it in the package, you might check the manufacturer manual on the internet.

Step 2: Preheat the oven

Next, preheat the oven according to specifications from both sources mentioned above, most likely between 220°F and 300 °F degrees Fahrenheit.

Step 3: Place your mold in parchment paper

Don’t put your sculpture directly into a metal pan, because it may cause stickiness. You should either use parchment paper or a glass dish.

Step 4: Center your sculpture in the baking tray

To make sure the heat spreads evenly, center your sculpture in the baking tray. Place your baking tray in the middle of the stove too.

Step 5: Let them cool for about 15-20 minutes

We don’t want our artwork cracked, so you better don’t touch them until they are completely cooled off. For a better result, wrap them with a kitchen towel. Wait about 15-20 minutes. After that, you might start with additional decorating.

NB: Please avoid putting plasticine or oil-based clay in the oven. It may cause fire or at least will melt into a puddle.

How To Harden Non-hardening Modeling Clay Without Oven

general tips for hardening clay

But there’s a type of clay too that doesn’t harden with heat – it needs to be hardened by other methods. Not only does not harden but can even become sticky if it’s exposed to heat. So, how do you harden a non-hardening modeling clay without an oven? The process can be tricky at first, but once you get the hang of it, creating your own projects will become much easier! Let’s take a look at some ways to make this happen and see which one is right for you.

In order to harden this type of clay, you’ll need to rely on something other than heat. You could use a chemical reaction, or using a de-humidifier. All of these methods can work for different types and brands of modeling clays – so keep reading to find out how each method will affect your project!

Chemical Reaction

When using a chemical reaction, you’ll need to add a binder such as glue or white vinegar. These are the most effective methods for hardening modeling clay without an oven on hand! The most common binder is glue, and it’s the one that you’ll find in most of your clay. You should add about a tablespoon to every half cup of modeling clay for this type of hardening method.

Use a dehumidifier

The most recent, and least invasive, method of hardening non-hardening clay is with a dehumidifier. You should place the opened package of modeling clays in front of one in order to maintain humidity levels during construction. Having a space heater or humidifier nearby will also work to regulate the humidity levels.

Portable heat source

Another option you have is to use a heat gun. This is one of the most popular methods for hardening modeling clay without an oven, and it’s also what you’ll find in your hairdryers at home. Heat guns are fairly inexpensive but they require some expertise to operate properly so only try this if you’re familiar with how to handle them safely!

If you don’t know how to use it, find someone who does. You can also use a hairdryer, but this is less effective than a heat gun for most purposes.

General Tips For Hardening Clay

  • Keep the work area neat and tidy; create designated areas (such as sheets) for drying out models when done building them so you don’t end up accidentally ruining all the fun by forgetting about one model’s wetness while working on another project.
  • If you’ve got a lot of clay on your hands and don’t want to put it away right now, wrap each model separately with an old washcloth (cotton is preferred) so that they’re not touching.
  • Put all finished products together on top of newspaper sheets when done working rather than leaving them on whatever surface they were built on.
  • You may want to use some cornstarch on top of nonhardening modeling clay before adding any type of paint or ink; this will help prevent bleed through onto other areas during application. Cornstarch is perfect because it absorbs any moisture from the air while still maintaining flexibility with each layer applied.
  • And finally, always keep any finished work out of direct sunlight while waiting for drying time. Sunlight can cause colors and details to fade over time.


In conclusion, you need to distinguish the type of clay you are using, because different types of clays will require a little more time and care when working with them. It is also important to read all the instructions that are provided with your clay before you begin to work on it.

For those times when things do go awry with your nonhardening modeling clay: don’t worry! There are several times when you need to be a little more flexible than usual when it comes to these types of clays. Happy modeling!

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