Air Dry Clay (ADC) is sold under various commercial brand names. However, the manufacturing process for most of these brands is similar.
Once the clay has been exposed to air, it takes about 24 – 48 hours for the clay to completely dry and solidify, depending on the thickness of your sculpt.
In this article, we look at various issues concerning ADC drying times and what you can do to increase or decrease the drying times.
Air Dry Clay Composition
Let us look at how ADC is manufactured to better understand how it dries any why it takes 1 to 2 days. Most air dry clay is made from natural ingredients that you can find in nature, including earthen clay, plant matter, and wood polyp etc.
If you mash and then blend paper with water, it will create a polyp that can be molded and then left to dry. As water evaporates from this polyp, it leaves behind hard and dry paper in the shape that you want.
Something similar can be done with other plant matter. For example, did you know that you can create good quality air-dry clay with common household cornstarch and baking soda?
There is actually a wikiHow page on that, explaining in detail how you can make your very own ADC at home. You can even add the color that you want to this clay.
All you have to do is mix water with starch, heat it up, and then whisk the dough until it starts to get sticky. Leave it to cool off and you have your own homemade ADC.
Do note that this clay will not be as reliable as commercial-grade ADC which uses a synthesized resin that is much more durable. It forms stronger bonds than cornstarch and also it is less likely to stick to your hands.
But the basic process of production is more or less the same.
Not all air dry clay is created equal! I definitely have my favorites, and you may enjoy reading my review article on 11 of the best brands on the market here!
Effects of Air Contact and Humidity
Have you ever made cookie or cake dough at home and left it out for some time? You will have noticed how it begins to harden around the surface even though it remains moist on the inside.
ADC reacts similarly when exposed to air. The only difference is that water escapes the clay from all sides and it also dries up from the inside like the surface area.
Once ADC has been manufactured, it is packaged in air-tight containers or plastic bags to ensure that it is not exposed to air. Packaging it in this way keeps the clay moist and soft, allowing it to last much longer.
Do note that the level of humidity around the surface area affects how long the clay will remain soft and moist. For instance, if you put it close to a humidifier or in the sunlight during a hot, sunny day, the clay will dry up faster.
If you keep it on your window on a cloudy, rainy day with high humidity in the air, it will take much longer to cure.
Effects of High and Low Temperature on ADC
Temperature is another factor that can have an effect on ADC drying times. If you heat up the clay in the oven or blow a warm hair dryer on it for a while, the temperature of water molecules goes up. This causes them to press harder and escape the clay mix at a quicker rate. Do note that if the temperature becomes too high, it may cause the clay to crack and fracture as moisture leaves it too quickly.
Conversely, if you package the clay and put it in a freezer, the temperature drops and causes the water molecules to condense. Some users have noted that the clay feels hard when it has been cold for a while and think it has hardened.
But if you keep it outside for some time and let its temperature normalize, the clay becomes soft once again.
Effects of Shape and Size on Drying Times
Another factor that can affect drying time is the size of your crafted artwork. With bigger ADC objects, water molecules from the core take longer to reach the surface to evaporate. In smaller objects, water molecules have less distance to move before they start drying up.
This is why smaller crafts dry faster than bigger objects.
The surface area of the craft also matters. You see, water molecules inside the clay can only escape from the surface. So if your crafts have a bigger surface area, they will dry up faster compared to when the surface area is smaller.
So if you press up the clay in the shape of a ball, it will take longer to dry compared to shaping the same volume of clay into a long stick-like shape which has a much greater surface area.
This is why clay figurines with delicate features like fingers and limbs dry up much quicker than thick, rounded statuettes.
Effects of Paints on ADC Drying Times
As most professional crafters will tell you, never start painting your work until it has fully dried up. To start painting it before that is a guaranteed way of messing it up.
Most types of enamel paints, particularly oil-based paints, form a layer of waterproof coating over craft. This makes it pretty difficult for any water molecules, which are still inside the object, to evaporate into the air.
The end result is clay with a weak core that hasn’t fully solidified. It is prone to breaking down on impact.
How long should you wait to let it dry? Two days is the bare minimum before you apply any paints. However, you may want to add two more days, just to be sure that the ADC craft has completely cured.
You can use some quick-drying methods to get it to dry faster. How to tell when your projects are fully cured is something that you will only be able to tell with time and experience.
Effects of Blocking One Surface from Air
ADC cannot dry effectively if the surface is not exposed to air. This holds true for all sides of your crafts, including its base.
Many professionals and regular crafters have noted that while most sides of the craft can dry at regular speed, the base surface at the bottom takes longer to cure. This is obviously because the base is pressed on your counter or table which prevents it from drying at the same speed.
There are a couple of ways to work around this. For a start, you can use a porous sheet to act as the base. A porous base ensures that the bottom surface dries at the same rate as the other part of your project.
You can also put your figurine on three or more raised platforms of equal sizes. This allows your crafts to dry from the bottom up uniformly.
Prolonging Drying Times for ADC Projects
You can also extend the drying time for your Air Dry Clay when the occasion calls for it. Suppose you are working on a particularly complex or big crafting project and something comes up in the middle of work. You may be worried about leaving it in the middle as it might dry up.
There is something you can do to prevent this from happening. Place your craft on a table and put a covering lid on top. This will help create a barrier to prevent the clay from drying too quickly.
If the covering lid is big enough to allow it, you can also put in a glass or bowl full of water under the lid. The water will add humidity level inside the covered area. In some experiments, we have managed to keep the ADC clay moldable and soft for up to a week with this trick.
Just make sure that the clay is kept away from sunlight and the room temperature is not too high.
Air Dry Clay is considered the beginner’s clay because it is easy to shape and cure. You don’t need a professional kiln to bake your projects once they are done. Just leave them on the shelf or your worktable and they will dry nicely in a couple of days.
One of its shortcomings is the relatively longer drying time, compared to baked clay. Two days may seem like a long time if you are in a hurry.
There are steps you can take to help them dry sooner, but they can be a headache and you also risk cracking the clay if you use quick-drying methods. For detail on methods to help air drying go faster, read our article here.
In addition, if you are hoping to make your air dry clay creations a bit stronger once finished, read our article on boosting its strength here.
If you have more questions or want to add something let us know!