The most frustrating part of working with air dry clay is drying it without it cracking in the process. There are a lot of things to keep in mind when working with air dry clay that will keep it from cracking during the drying process. So how do you dry air dry clay and keep it from cracking?
To dry air dry clay it is best to place the clay on a grill tray to ensure that every side has some airflow and then cover thinner parts with a damp piece of cloth. Cover the entire sculpture with a thin sheet of plastic and let it dry for at least 72 hours.
Here are the most effective ways to keep air dry clay from cracking:
- Use a wax lined surface
- Knead the clay before shaping it
- Don´t roll too thin
- Add just enough water
- Create strong joints
- Allow it to dry from all sites
- Store leftover clay correctly
We’ll explain why air dry clay cracks in the first place and how you can keep it from cracking as well as how to dry it properly in the following.
How to Keep Air Dry Clay From Cracking
Air-dry clay has many benefits, but it also has limitations. Though it dries slowly enough to enable molding, it begins reacting to air immediately. It means the very slow drying and hardening process actually begins as soon as the clay leaves its packet. As you knead and shape it, it is inevitably losing water and becoming stiffer.
The good news is there are steps you can take to remedy this. Here’s some advice on sculpting with air-dry clay and preventing crumbling.
Air-dry clay only breaks easily when handled wrong. If you want to know how to avoid breaking air-dry clay when handling it then consider reading another of my articles where I explain just how easily air-dry clay can break.
1. Use a Wax Lined Surface
Air-dry clay is extremely sticky. If you get it on your work surfaces, you may have trouble getting it back off again.
So, we strongly recommend you line surfaces with wax paper or, alternatively, silicone or vinyl placemats. It’ll also minimize the amount of stress you need to put on the clay because you won’t be yanking it off the counter.
2. Knead the Clay Before Shaping it
Once you’ve taken the clay out of its packet and before you start shaping, spend several minutes kneading it with your knuckles. This process is known as ‘conditioning’ and it’s an easy way to get your material soft and ready for rolling.
Firm kneading loosens up all the platelets in the clay and helps them assimilate.
3. Don’t Roll Too Thin
The general rule of thumb for air dry clay is around a quarter inch. This is the optimum thickness for speedy drying with minimal cracking. Sculpting with this material, though low maintenance in some respects, requires a little more care in others.
The key to success is striking the right balance between durability and efficiency.
The thinner the material, the faster it will dry and harden. The faster the clay hardens, the greater the number of cracks. So, it’s really important to find that middle ground at approximately a quarter-inch thickness.
4. Add Just Enough Water
The same rule applies to water. Adding small amounts of water during molding is strongly recommended. The clay will crack and warp as you attempt to shape it because it is soft and pliable, to begin with.
As with ceramic clay, it’s good practice to smooth over imperfections as and when you see them develop. This is easy to do with unhardened clay. Simply dip a fingertip into lukewarm water and rub gently until the crack disappears.
There’s a catch though; add too much water and you can easily oversaturate the clay. This makes it sticky and difficult to manipulate.
It will also add hours to the drying process and, thus, more opportunities for a finished work to crack. Keep the clay moist but not very wet. Remember, you can always add water, but you cannot take it away.
5. Create Strong Joints
Seams and joints are the most vulnerable areas of a clay structure which is why single-piece shapes are always the strongest. As most clay creations include multiple bonded pieces, you should know how to create high-quality connections.
First, the two surfaces destined to be joined together must be reasonably dry.
You’re going to be adding a wet glue-like substance called ‘slip’ to create the join so avoid adding extra moisture. Using a toothpick, score a crosshatch pattern on the connecting surfaces.
This will increase the strength of the seam by enabling sections of the clay to interlock rather than just press together.
Slip is a rudimentary ‘glue’ used to stick pieces of clay together. It is made by soaking clay scraps in water until they soften into a slurry. This mixture is stirred and pushed through a wire mesh (or similar device) to remove lumps. It is then added to connecting surfaces (usually with a paintbrush) as an adhesive.
If you need help with this, there are countless guides and slip recipes online.
6. Allow It to Dry On All Sides
One common mistake is to put a clay creation to one side after molding and leave it totally untouched. The most consistent way to dry is on all sides.
I will explain how to dry air dry clay later in the article.
In other words, you should try to turn the object a few times. Even a completely spherical clay ball will develop an untouched, slow-drying section if not turned. Every surface needs some exposure to the air.
Air-dry clay can take anywhere between 24 and 72 hours to dry completely. It depends on environmental conditions such as indoor temperature, humidity, exposure to sunlight, and whether the clay is drying evenly on all sides.
Don’t forget to flip it over and prevent a wet, soggy base. A good place to dry clay is in a warm, clean cupboard or cabinet.
7. Store Leftover Clay Correctly
The healthier your clay is at the start of the sculpting process, the better your chance of producing a perfect project. Leftover clay must be sealed in an airtight container such as a Tupperware box.
Sandwich and refrigerator bags are fine too provided they are sealable. If there’s very little or no air, the clay will stop drying and remain malleable.
Storing partially completed works is trickier, especially if they are very large pieces. Every sculptor has its own technique, so you may need to experiment a little.
Popular strategies include wrapping clay works with clingfilm to trap moisture inside or lightly misting with a gardening spray bottle. This works best if you go back and continue working within 24 hours.
If you plan to create a very large piece such as a spherical ball much bigger than a fist, consider using bulking techniques. You can achieve the effect by molding solid sections of clay, but this is often wasteful.
It requires the use of huge volumes of material and risks a long and uneven drying process. Instead, many sculptors choose to create a hollow clay mold around something very lightweight such as tinfoil.
The risk of cracks is significantly lower because a smaller volume of clay is being used.
If the clay still cracks then don´t panic. You can fix cracks in air-dry clay quite easily. You can read how to fix cracks in air-dry clay in another guide that I wrote. You will learn how to successfully fix cracks of any size.
How to Dry Air Dry Clay Without Cracking
Follow these steps to dry air dry clay properly:
- Get a grilling tray or another type of mesh
- Place some parchment paper on the mesh
- Place the air dry clay sculpture on the mesh
- Cover thin parts of the sculpture with a damp towel
- Cover the entire sculpture with a plastic sheet
- Let the clay dry for 72 hours
- Remove the sheet and test if the clay is dry
This is a guide on how to dry air dry clay properly. It focuses on drying the clay slower and as safely as possible to avoid cracking.
1. Get a Grilling Tray or Another Type of Mesh
First, you will need a grilling tray or some other sort of mesh that will be used to ensure that the clay has some air flow all around it including the bottom side.
Any type of mesh will do as long as it can hold the clay and allows air to reach the bottom part of the sculpture.
2. Place Some Parchment Paper on the Mesh
Cut some parchment paper to size so that it fits on the mesh.
The parchment paper will ensure that you can easily remove the dried sculpture from the mesh later on.
This step is especially important for heavier sculptures.
3. Place the Air Dry Clay Sculpture on the Mesh
Place the sculpture on the mesh on top of the parchment paper.
Make sure that you place the sculpture in a location where no cold or hot air is circulating. Also, keep the sculpture away from any heat source or the sun as this may cause cracking during the drying process.
4. Cover Thin Parts of the Sculpture With a Damp Towel
If your sculpture has parts on it that are significantly thinner than other parts of the sculpture then it is best to cover these parts with a damp towel or a damp piece of cloth.
This will make it so that the thinner parts dry slower than normal which will help the whole sculpture to dry as evenly as possible.
If you don´t do this then thinner parts of the sculpture will dry faster resulting in internal tensions that might cause cracking.
5. Cover the Entire Sculpture With a Plastic Sheet
The final step before leaving the sculpture to dry is covering it in a thin plastic sheet.
The plastic sheet will protect the clay from hot or warm air and it will ensure that the clay dries very slowly.
The slower and the more evenly the clay dries the better.
6. Let the Clay Dry for 72 Hours
Now, let the clay dry for as long as it needs.
Most types of air dry clay will be dry within 72 hours but depending on the type of clay and the size and thickness of the sculpture it can also take 4 to 6 days until the clay is fully dry.
You can often tell if an air dry clay sculpture is completely dry by looking at it and touching it.
If the clay has turned a lighter color then chances are it has dried. When there are no dark spots visible on the surface then it might be completely dry.
You can also carefully touch the clay and see if the clay is significantly colder than its surroundings. Clay cools down as the water inside it evaporates. If the clay is very cold then the process might still be ongoing and you should leave it for another 5 hours.
If the clay has room temperature then chances are the drying process is done.
Finally, you can also press your fingernail into the surface of the clay. If the nail pushes in easily then the clay is not yet dry enough.
7. Remove the Sheet and Test if the Clay is Dry
Once the clay is completely dry all you have to do is remove the plastic sheet and dispose of the parchment paper.
You can seal your clay if you want to or fix any cracks if you can find some
What Types of Air Dry Clay Are Available?
There are a number of different brands available including Pearl Paperclay, Creative Paperclay, Activa Plus Air Dry Clay, and Crayola Model Magic which is perfect for sculpting with children.
It’s also possible to make a very basic homemade ‘clay’ called cold porcelain out of corn starch and white glue. While not technically clay, it shares similar characteristics and can be sculpted into shapes and left to set.
Is Air Dry Clay Stronger Than Ceramic Clay?
The lack of heat treatment means ceramic clays will always be stronger when finished than air-dry clays. Treated ceramics are non-porous and, therefore, water-resistant which makes them extra tough.
If you want to know how durable air-dry clay really is then consider reading my article on the durability of air-dry clay.
However, if afforded plenty of time in optimum conditions to fully set and harden, air-dry clays can also be very durable and long-lasting.
To ensure maximum longevity, air-dry clay creations must be kept away from water and humidity. Adding sealers and paints increases durability and makes up for the fact this particular clay variety is less tolerant of fine details.
While air dry clay is not naturally waterproof, materials can be added after hardening to increase its water resistance. Though we haven’t tried the technique ourselves, some artists apply a coating of half PVA glue to half water. After it’s dry, they add a coat of grey acrylic paint for protection.
Once this is dry, they add two topcoats of the desired shade. The method is reportedly good for creating water-resistant outdoor sculptures. We advise you to practice on a small project first.
Hi, I am a passionate maker and professional prop maker for the entertainment industry. I use my woodworking, programming, electronics, and illustration know-how to create interactive props and puzzles for Escape Games and marketing agencies. And I share my knowledge and my experience on this blog with you so that you can become a maker yourself.