Xinxiang Ceramic Mug Manufacturer, in the previous article “Ceramic mug crack causes and prevention methods” the concept of aging ceramic mug clay was covered. The aging of clay is not introduced in many specialized ceramic mug production processes. This is due to the fact that the aging process is low in technical difficulty and is often unintentionally overlooked. This link is technically difficult, its importance is also low? On the contrary, aging is a very important link in the production of ceramic mugs. If the quality of ceramic mugs is determined by the quality of raw materials, if the clay aging is not good, the same production of high-quality ceramic mug. Today, Xinxiang Ceramics Factory will give you an explanation of the aging of clay.

1. What is aging?
Aging, commonly known as “boring material” or “trapped mud”, it is not simply to mix the mud pile on the side regardless. It is a controlled process of storing the vacuumed clay in a specific environment for a certain period of time.

You can think of it as the “waking” process of mixing noodles. When the dough is made and covered with a damp cloth and left to rest for a while, it becomes softer, more elastic and more malleable. The resulting pasta is both full and flavorful. Aging is the “waking up” of the clay.

2. Why aging?
If there is a lack of aging, clay is like a poorly trained army with poor internal communication, once it goes into battle (into the molding and firing, it will easily collapse.  it is easy to collapse. The purpose of aging is to create an elite force.

2.1 Promote the uniform penetration of water - to solve the “uneven wet and dry”.

Freshly practiced clay, from a microscopic point of view, the distribution of moisture is uneven. Some particles are full of water, while others are still “thirsty”. During the aging process, the water will be through the capillary effect, from the moisture of the place of the slow migration to the place of the water is less, to realize the “microscopic water adjustment”. Only through this process, the overall water content of clay can be highly consistent. The biscuit is dried and firing can achieve synchronized, uniform contraction, greatly reducing the risk of cracking due to uneven contraction stress.

2.2. Increase the plasticity of clay - make the clay “more obedient”.

In a humid, anoxic environment, the organic matter in the clay will undergo anaerobic fermentation, producing organic acids and other intermediate products. At the same time, the capillaries in the clay will be fully filled with water, and the lubricity between the particles increases. These combined effects will result in a stronger bonding of the clay and a more pliable and obedient texture. Only then will the workers in the drawing or rolling molding, the clay has good ductility and is not easy to “pull hair” and “pull crack” phenomenon. It is also less likely to break when making parts that need to be bent, such as handles.

2.3 Exhausting residual air - eliminating the “invisible bomb”.

Even after vacuum molding, there are still some tiny air bubbles left in the clay. During the aging process, the clay will be further compacted by its own gravity, and the process of water migration will also help to squeeze out, merge and eliminate these tiny air bubbles. This eliminates the need for the bubbles to expand during firing and break through the body of the clay to form “pinholes” or “cracks”.

2.4 Adequate hydration - “chemical maturation”.

Clay minerals (e.g. kaolinite, montmorillonite, etc.) in the clay need enough time to come into full contact with water in order to fully hydrate, expand, and exhibit their optimal physicochemical properties.

3. How to operate the aging?
Ceramic factories need to establish a standard aging process, which is a prerequisite to ensure stable quality of clay.

Step 1: Clay practicing and molding

After being extruded through the vacuum clay trainer, it is best to make the clay directly into shapes suitable for storage, such as brick-like or cylindrical shapes. This saves space and is easy to manage.

Step 2: Sealing and wrapping

This is the most crucial step. The clay block must be wrapped tightly with airtight plastic film (such as thick PE or PVC film), leaving no gaps. Clay in the aging link, can not be air-dried, the same can not be the second absorption of water, if the surface of the clay once the air-dried crust, the significance of aging is lost. Seal the clay block with plastic film to create a stable anoxic environment to promote anaerobic fermentation and chemical reaction.

Step 3: Storage and stacking

Neatly stack the wrapped clay blocks in a special “aging warehouse”. The aging warehouse in the ceramic factory needs to avoid direct sunlight, the ventilation should not be too strong (to avoid the wind through the hall), the ground is preferably cement floor, if it coincides with the rainy season need to do moisture-proof treatment.

The fourth step: resting time

Cover the stacked clay with a layer of plastic or canvas, and let the clay quietly “recuperate”. Let the clay rest for at least 7 days, 15-30 days is recommended. The longer the time, the better the result, of course, but also need to consider the production cycle of the ceramic factory and inventory costs.

4. Precautions for different seasons and weather
The production of ceramic mugs is greatly affected by the degree of temperature and humidity in the environment, and the aging process is even more so.

In spring and summer, such high temperature and high humidity season, the environment temperature is high, humidity is high, and the bacteria and microbial activity in the clay is strong. Therefore, the aging speed will be accelerated and the effect will be better. Also in the high temperature and high humidity season, if the clay block is not sealed tightly, the clay will be over-fermented, producing sour smell and leading to mold, instead of destroying the performance of the clay.

In the fall and winter, aging in the low temperature and dry season. The aging will slow down and the chemical reaction and moisture migration will be weakened, which will require a longer aging time than spring and summer to safeguard the performance of the clay. Because of the seasonal dryness, piles of clay need to be covered with wet sacks on top and should be moisturized. If the temperature of the warehouse will be below zero, basic heating is needed to maintain the temperature of the aging warehouse at no less than 5°C to avoid freezing of the clay.

5. How to judge the aging effect?
What kind of clay is considered well aged? We can judge from the following points: Touch: the whole soft, elastic, “meaty”. Hand break open, inside and outside the color, soft and hard consistent, no white hard core. Color: the color is uniform, slightly darker than the new clay, appears more “moist”. Smell: there should be a light, earthy fishy or sweet smell, rather than pungent sour smell. From these 3 aspects you can judge whether the aging is qualified. In the ceramic mug molding session, this kind of clay is even better, not easy to crack and not sticky.

Summarize
The aging of clay seems to be simple, but in fact it is not simple at all. It may seem like a simple thing to wrap the clay in plastic and leave it for a few days. But the reaction of the clay itself in this “vacant period” can be said to be a kind of metamorphosis. We all know that painting is a kind of art, in fact, making ceramics is also a kind of art. Painting in the pigment needs to be aged, ceramic production in the clay also need to be aged. We ceramic mug makers, just let the clay to play its optimal performance, molded into a variety of shapes, the exquisite ceramic mugs delivered to your hands, so that the best use of its material.