Air-dry clay is probably one of the most used clays for hobby crafters. It is easy to use and its biggest advantage over other similar products is that you don´t need a kiln to fire it. Air-dry clay will harden on its own as soon as it gets in contact with enough fresh air. One of its biggest disadvantages, however, is its durability. But is it really as bad as people say? Just how durable is air dry clay really?
As a whole, air dry clay is not as durable as regular clay that has been fired in a kiln. Air-dry clay is fairly strong but it is recommended to use an armature or something similar to support bigger sculptures. Water will soften hard air dry clay so either seal the clay or keep it away from water.
Bigger sculptures, more intricate sculptures, and things like mugs and vases should not be made with air-dry clay. Air-dry clay is simply not strong enough to support the weight of bigger sculptures on its own and even if the clay is dry it will never be water-resistant unless it is sealed properly.
Does Air Dry Clay Break Easily
This is another thing that you either heard a lot or maybe even experienced yourself already. Air-dry clay tends to break easily, or does it?
As a general rule, air dry clay is not as robust or strong as clay that has been fired in a kiln but that does not mean that it breaks easily. Air-dry clay breaks easier than regular clay but it is still quite durable and it is definitely strong enough for most smaller and mid-sized projects.
I think the rumor that air dry clay breaks easily comes from cracks that often appear when air dry clay is drying.
Unfortunately, it is kind of hard to avoid these cracks because they appear during the drying process when the water inside the clay evaporates which leads to the clay shrinking, and when this happens too fast then too much stress is put on the internal structure of the clay and it starts to crack.
You can read more about air dry cracking and how to avoid cracks in air-dry clay in another article that I wrote.
But once the air dry clay has fully hardened it will be quite strong and it won´t break easily anymore. So you can use air-dry clay for things like decorative plates, little figures, pen holders, or something similar and it will be durable enough to last a long time without any issues.
Just keep the clay away from water!
How Strong is Air Dry Clay
I told you repeatedly in this article that air dry clay is not as strong as regular clay but still pretty strong on its own. But how strong is “pretty strong”?
As a whole, air dry clay is quite strong on its own. It can withstand a moderate amount of pressure and smaller pieces can´t be snapped in half easily. Air-dry clay can be made stronger if varnish or epoxy resin is applied to it after it has dried.
You can also glue broken air dry clay quite easily as long as it didn´t break into a million pieces.
So even if it breaks you can still glue it back together with relative ease. You can read my article on gluing clay back together right here if you want to know more about that.
There are a few things to keep in mind when working with air dry clay, however.
For one, air dry clay is best used for smaller to medium-sized sculptures. The bigger the sculptures are and the thicker the clay walls are the easier the air dry clay breaks and the weaker it will be in the end.
And secondly, air dry clay is not strong enough to support a lot of weight on its own. So if you want to create a sculpture of a horse, for example, then you have to use some sort of support in the legs of the animal or they might break later on.
Keeping Air Dry Clay From Cracking
I already mentioned that air dry clay tends to crack easily during its drying process but how can you avoid this issue?
As a whole, to keep air dry clay from cracking the clay has to be dried slowly. The best way to control the drying speed of air dry clay is to keep the clay in a colder area while it dries. Putting the clay in a plastic bowl covered by some foil with holes in it will also keep the clay from cracking.
When air dry clay dries water evaporates from the clay causing the clay to shrink very slightly.
This process puts a lot of stress on the clay which eventually leads to cracks. Keeping the clay in a colder area will ensure that the clay doesn´t dry too fast.
Another trick is to put the clay in a plastic bowl. Then cover the plastic bowl in some foil and poke a few holes in the foil.
The foil will keep the water from evaporating too quickly. This will make the clay dry slower.
Keep in mind that the clay will probably take a lot longer to dry this way than the packaging says!
There are a few other ways to keep air-dry clay from cracking. I wrote an article explaining most of these methods in more detail if you want to know more about how to keep air-dry clay from cracking.
How to Ensure the Longevity of Your Air Dry Clay Project
Most of you probably want to know how to ensure that your air dry clay project has a long life. And you will be pleased to hear that there are actually quite a few things that you can do to ensure the longevity of your air dry clay project.
For one, you can seal your air dry clay after you painted it to make it more durable and to protect it from the elements. This can be done by applying varnish or epoxy resin to your finished sculpture.
I have written a whole article about sealing air dry clay properly that you read right here. It will talk you through the pros and cons of sealing air dr clay in different ways, it will also explain exactly how to seal your air dry clay using each of these methods and in the end, you will know exactly what kind of sealer is best for your project.
Another thing that you can do to ensure that your air-dry clay has a long life is to keep it away from water and direct sunlight. Water will make your air dry clay soft again unless it is sealed properly, and the sun might cause cracking in your air dry clay especially if you are living in a very humid environment.