Why clay cracks when drying
When a potter puts a lot of time and effort into a piece of pottery, it is frustrating when the clay cracks as it dries because it destroys the work that they have done. Consequently, we looked for a way to lessen the influence of the factors that cause cracking.
If some areas of a ceramic item dry faster than others, the piece will shatter while it is drying because of the uneven drying time. When clay dries, it becomes more compact. The pottery will experience internal stress if one of the pieces of clay contracts at a faster rate than the others. Clay breaks apart as a result of the pressure being applied to it.
Although uneven drying is the most common cause of cracks in ceramic clay, there are other factors to consider. Keep reading to find more information about the condition and how to stop more cracking.
When a potter puts a lot of time and effort into a piece of pottery, it is frustrating when the clay cracks as it dries because it destroys the work that they have done. Consequently, we looked for a way to lessen the influence of the factors that cause cracking.
If some areas of a ceramic item dry quicker, the object will break throughout the drying process. As the clay dries, it contracts. If one piece of clay shrinks quicker, internal stress will develop in the pottery—clay fractures to withstand the pressure.
The most frequent reason for ceramic clay cracking is uneven drying, but more aspects must be considered.
Continue reading to learn more about the ailment and how to prevent more cracking.
What Causes Clay To Crack When Drying?
If the thickness of the walls is not uniform, the pottery clay may crack.
Ceramic clay can shatter as it dries because of variations in the thickness of the clay. This is because areas of clay that are smaller will dry more quickly than those that are larger.
When clay is exposed to air and allowed to dry, the water in its deeper layers will rise to the top, where it will evaporate. It takes the water more time to disappear, depending on how far it has to go before reaching the surface. As a direct consequence of this, heavier clay sculptures take longer to dry.
Consequently, mugs and bowls often acquire base cracks after drying. The fact that the piece’s base is thicker than its sides contributes to this. Typically, pot and cup lips dry up far more rapidly than bases.
Due to the intricate details and embellishments, ceramic clay may crack.
Thinner components are more abundant than thicker ones in finely engineered ceramics. The result is that the details tend to lose their freshness quicker than the main body. This also applies to ceramic designs with acute angles instead of wide arcs.
This is one reason ceramic handles are more susceptible to breaking than other components. Due to the several angles at which the handles are exposed to the air, water rapidly evaporates.
Larger fragments of ceramic clay fracture.
The greater the size of your ceramic piece, the greater the possibility that it may break when it dries. If the piece is large, the surface will dry up faster than the lower layers since there is more surface area.
At more considerable depths, water must travel a longer distance before it can exit the clay, and this will need more time. Large clay slabs, such as large tiles or plates, have a higher risk of cracking and deforming than smaller clay pieces.
As a direct consequence, the margins will dry off very quickly. In addition, just a single large surface is open to the air.
Not Wedging your Clay Enough
Wedging clay is essential because it creates a uniform consistency throughout. This consistent uniformity is known as homogeneity. Certain portions of the clay’s body will be thick and dry if it is not sufficiently wedged. Other areas will be softer and contain more water.
When making pottery from unwedged clay, the water content is immediately uneven. Consequently, your ceramic clay is more likely to break as it dries.
Achieving Clay Particle Alignment
Clay is composed of minute, flat, and elongated particles. In unworked clay, these particles are disordered and scattered.
As the potter refines the piece, the clay particles become more aligned. This is especially true concerning wheel throwing. A piece of thrown pottery will have particles aligned in the same direction. However, the clay bits on the artwork’s foundation are more carelessly put.
During the drying process, clay particles contract more along their narrow width than along their length. If the clay particles on the side are aligned, the object will contract in one direction more than the other.
In contrast to the sides, the base of the clay has not been as wholly prepared. As a result, they have formed more arbitrarily. Consequently, the ground often drops less dramatically than the sides.
Under conditions of low humidity, ceramic clay may crack.
Clay dries out quicker in conditions with lower relative humidity. The relative humidity will generally be lower in locations and much cooler seasons. The clay used in ceramics does not crack even when it is allowed to dry out very quickly. The drying of your greenware will be much more difficult as a result of this factor.
Cracking may also be caused by a drafty environment or by storing ceramics in a drafty environment. When clay is exposed to wind, the drying process increases significantly. Which kind of clay are we talking about here?
Clay with low plasticity has a greater propensity to crack as it dries. Many different interpretations may be made for this. The individual clay particles that make up plastic clay are far smaller.
As a result, a more incredible surface area is available for the water to cling to on the clay. In addition to this, the distance between the particles that make up the clay is correspondingly higher.
Despite not being a flexible clay body, porcelain clay holds a great deal of water. As a result, it tends to shrink somewhat upon drying. Consequently, it is more susceptible to cracking. know how to preserve clay properly to use it later without cracking issues.
There are minor flaws in freshly manufactured pottery.
There is a possibility that recently finished work may have tiny fissures around its edges. This is a result of the fact that handling clay causes it to dry very quickly. These small fissures have resulted in the formation of weak spots.
This is because the clay in the minute fissures dried up faster than in the surrounding area. As the clay in your pottery dries, it’s possible that little fractures can ultimately become larger ones.
How to Prevent the Cracking of Pottery Clay
The following are five fundamental approaches to minimizing the risk of cracking while working with clay in ceramics.
Maintain a consistent clay thickness.
Check that the thickness of your pottery is consistent all the way through. This is especially relevant to the bases of cup sets, bowls, and vases.
A device that resembles a needle may be used to determine the thickness of the base. A handle is attached to the needle that makes up a needle instrument. Put the needle into the bottom of the pottery until it reaches the potter’s wheel head. As soon as your finger makes contact with the surface of the clay, slide it down the needle.
After taking the needle out of your skin, measure how far your finger is from the very end of the needle. The thickness of the base of your pottery may be determined using this measurement.
In general, pottery should be thinner.
You want the walls of your pottery to be as thin as you can get them. On the other hand, you can decide to construct something more substantial or with more significant walls. In such a case, you may dry pottery evenly using some of the concepts described below.
To prevent your ceramic clay from shattering, cover it.
By placing your pottery in a plastic bag, you can control the pace at which it dries out. The relative humidity within the bag increases as the moisture initially present in the clay dries out. A plastic structure that resembles a tent may be used as one technique to cover the ceramics. If your pottery is on a batt, you may close the bag by tucking the edges of the bag under the batt.
In addition, you may improve the bag’s ventilation by cutting a hole in the bottom of the bag and leaving it open. It depends on the relative humidity of your surroundings and whether the bag should be left open or closed while storing its contents. You may need to experiment.
Consider that water tends to condense on the inside of plastic bags. There is a possibility that the bag will come into contact with the surface of the clay. If this occurs, your clay may get damp and leave markings on your pottery.
Covering the pottery with a soft cloth or paper towels is a good option if this is likely to occur. These will absorb the moisture in the bag and prevent your ceramics from sticking.
Protecting Rapidly Drying Areas
Covering the parts of clay that dries more rapidly is a second way of achieving uniform drying. The handles and lips should ideally be covered with plastic. This permits them to dry at the same pace as your other ceramics.
You may also get the same look using wax resist. Wax resist, a waxy emulsion, may be applied on handles and lips to reduce moisture loss.
Remember to leave a small strip unwaxed when adding wax resist to the handle. This provides a means for moisture to escape. know if using microwave with pottery and ceramic items for drying safe and wont cause cracks in this article.
Using a Damp Box to Prevent Pottery Clay from Cracking
A wet box is another alternative for safeguarding your ceramics. To fast construct, a damp box spread a 1 to 2-inch layer of plaster in a plastic container. After the application has hardened, water may be added to adjust its moisture content.
Cover the moist box that contains your freshly shaped pottery. This produces a humid, draft-free atmosphere where the clay may slowly dry. You may regulate the drying process by altering the plaster’s moisture content. By leaving the lid slightly ajar, additional can be obtained.
You may alternatively set a pot with a thicker base above a dry plaster batt. To finish the artwork, cover it. The plaster repels water from the foundation. As a result, the foundation and thinner walls continue to dehydrate.
Conclusion
A variety of elements impact Clay’s behaviour. There might be a lot of reasons why your ceramic clay is breaking. Testing will probably be required. However, by following the previous methods, you will be able to identify the cause of your clay’s cracking.
FAQ
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How can clay be prevented from cracking while it dries?
To efficiently dry, air-dry clay projects must be exposed to the air from all sides simultaneously. This will reduce the likelihood of cracking and warping. We recommend drying products on a screen or cookie rack, where airflow is consistent on all sides.
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What causes the clay to crack?
Generally, stresses inside the clay generate fissures. Due to its inclination to contract throughout the drying and fire processes and after it has been burned, clay is continually subjected to significant stress. It may crack when the strain is too much for the clay to withstand.
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How does one produce durable clay?
The easy remedy is to boil and gently dry it to prevent cracking. Carefully measure the ingredients, cook the dough well, roll it to a thickness of 1/8 to 1/4 inch, and allow it to dry slowly over the first several days. To achieve even drying, carefully rotate the pieces every several hours.
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Does clay crack if it soon dries?
Due to quick drying alone, your ceramic clay does not crack. However, it makes it more difficult to dry your greenware consistently. Additionally, a drafty location or putting your ceramics there may cause cracking. If you expose your clay to the breeze, it will dry more quickly.
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