Each type has its own unique characteristics and properties. But what if we could combine these characteristics?
Why mix different types of clay?
There are many reasons to mix different types of clay. One reason is to combine clay in different colours to create beautiful patterns. This technique is called nerikomi, or millefiori in Italian, and agateware in English.
This allows you to achieve all kinds of beautiful colour combinations, ranging from a marble effect to more complex patterns.
Another reason is to change the composition of your clay. For example, you can add ball clay, which is a highly malleable clay sold in powder form, to make your clay more workable. Alternatively, you can add fire clay to increase the firing temperature of your clay.
Finally, you can recycle leftover clay from previous projects by combining it with new clay. However, this can be risky if you are unsure what type of clay it is. In such cases, it is better to test the clay remnants first by firing them at a low temperature.
What should you definitely take into account?
Combining two types of clay always carries risks. If they are not compatible or are not mixed sufficiently, your piece may crack, fall apart or even explode in the kiln. To maximise your chances of success, there are a number of factors to consider:
- Make sure you only combine clays with the same firing temperature.
- Ideally, choose clays with a similar moisture balance and shrinkage. You can test this by making a small bar from each type of clay, measuring it carefully before and after firing. If one type of clay shrinks much more than the other, they are not compatible.
- Allow yourself up to an hour to mix the clays. You can choose from different wedging techniques. If this is your first time combining clays, use an amount that you feel comfortable with. Also, make sure you add enough water if you are working with harder clay.
- Once the clay is mixed, it is best to leave it for a week. After this time, the clay will have become more workable. Some potters leave mixed clay for much longer, up to several months or even a year. If you choose to leave it for this long, it is best to do a test firing after one week. This will ensure that the clay is well mixed, so you won’t be disappointed months later.
Mixing clay is not an easy task. Therefore, it is quite possible that many of your pieces will not survive the kiln. However, remember that this will give you valuable experience. The more experience you gain, the better you will be able to tell when the clay is mixed well.
The better you will also be at judging which combinations will work. So don’t give up!
