Water spots: when the stone is wet pasted with cement, the hygroscopic substances enter the interior of the stone, resulting in wet marks on the stone surface that are not easy to dry naturally.

The stone nursing career without treating water spots is incomplete, and it is absolutely an industry expert to easily solve water spots!
Water spots are difficult to treat, which is the consensus of the industry. Such as psoriasis and vitiligo, which can not be cured for a long time and occur repeatedly. Some people call it stone cancer.
Water spots are not a bad disease, but they are definitely a stubborn disease. It is not a bad disease because it does not cause structural damage to the stone itself and will not reduce the service life of the stone! Say it is a stubborn disease, because water spots really affect the decorative effect, and it is difficult to treat!
Review the definition of water spot: when the stone is wet pasted with cement, the hygroscopic substances enter the interior of the stone, resulting in wet marks on the whole or part of the stone surface that are not easy to dry naturally. Since it is a wet mark, it must be accompanied by the deepening of color, resulting in significant color difference of stone! The bright stone surface has become a big flower face, which is unacceptable to stone lovers!
Water spots mainly have the following characteristics (also the basis for distinguishing water spots):
one:
To the naked eye, there are traces similar to water wetting;
two:
These wet marks are always dry or not easy to dry completely;
three:
Even if the sun shines or roasts with fire, the wet mark remains after that!

Polished grey marble slab

Why are water spots difficult to treat? First, many people do not understand the mechanism of water spots. They blindly use chemicals. The drugs are wrong and cannot be cured; Second, there are many causes of water spots. The same method is effective in a stone, but it will be ineffective in another place!
The reasons for the formation of water spots are complex, including the stone itself, such as more penetrating micropores; There are installation reasons, such as using inferior cement or adding inappropriate cement additives; There are also reasons for later maintenance, such as cleaning the rust yellow spots or cement spots on the stone surface with strong acid; There are other conditions, such as acid rain or infiltration of some liquids.
To sum up, water spots can be roughly divided into four categories, and their formation mechanism and treatment methods are different:
Type I water spots
Water spots with alkali silica gel as the main component, in brief, permeate the water containing gel material inside the stone.
Type II water spots
Water spots formed by hygroscopic saline and alkali silica gel are, in short, permeated with moisture absorbing substances inside the stone, resulting in moisture absorption and moisture formation.
Type III water spots
Water spots formed by hygroscopic saline and alkali silica gel are, in short, permeated with moisture absorbing substances inside the stone, resulting in moisture absorption and moisture formation.
Type IV water spots
Water has dried, leaving traces similar to water spots, which are also known as "false water spots".
After understanding the classification of water spots, the formation mechanism of different types of water spots is also different. How are the four types of water spots formed?

Type I water spots
Saline alkali silica gel from cement
Let's first look at a phenomenon: the use of cement mortar wet paste method to paste stones with high water absorption is easy to produce water spots.
The specific manifestations are:
1. If the stone is not protected, large areas of water spots appear;
2. If the stone protection is not uniform, there will be water spots like brushing marks;
3. If the protection is omitted on the side of the stone, water spots appear on the edge of the stone and penetrate radiation to the center.
It can be seen that such water spots occurred shortly after the installation of the stone. The main reason is that some substances were inhaled, resulting in the formation of wet marks. It is easy to breathe in cement gel without any protective or unprotected stone. This material is a gel gel formed mainly from cement silica gel. This kind of gel has tiny pores, adsorbs and stores water, penetrates and sticks in the stone gap, so that the light reflectivity of stone surface changes. It looks like the stone is wetted.
This situation is not unique to the first type of water spots, but may co-exist with other types of water spots!
Type II water spots
Hygroscopic saline alkali from various sources
As we all know, stone has adsorption and water absorption (good protection and low water absorption)! If the stone is exposed to the air for a long time, it will absorb moisture from the air or other sources. If a part of the stone has stronger ability to absorb water and faster speed, it will form a normal stone surface with almost no wet mark change, and the part with strong water absorption has a deeper color, which will become water spots!
The part with stronger water absorption must go deep into the material that is easier to absorb moisture - hygroscopic saline alkali. The source of hygroscopic salinization is similar to that of alkali silica gel. It also permeated the stone surface from the back of the stone when the stone was pasted.
Under normal circumstances, there is less hygroscopic saline alkali in general cement, and water spots will occur in less than one. However, the probability of water spots will be greatly improved if:
1、 Strong alkaline cement or inferior cement is used;
2、 Improper cement additives are used;
3、 The cushion, sand and other base materials under the stone contain soluble saline alkali, which moves upward with water;
4、 Use strong acid to clean the rust spots or cement spots on the stone surface. The acid reacts with pollutants to form hygroscopic soluble salt, which goes deep into the micropores of the stone;
5、 The low-quality protective agents used, especially some strong alkaline low-quality protective agents, are easy to form hygroscopic alkalis.
Type III water spots
Effects of moisture and capillary migration
This kind of water spot is easy to understand, that is, the stone absorbs water and brings pollutants! There is a continuous source of water around the stone, such as wet soil under the ground or on the back of the stone, or the groundwater level is too high (outdoor stone); Or there is a pool nearby, a toilet with frequent water seepage, ponding on the roof, etc;
As the water flows to the stone surface far and continuously, with the evaporation of water, hygroscopic saline alkali and other substances will gather to the stone surface, forming serious water spots!
Type IV water spots
Watermark similar to water spots - false water spots
Because the stone is in a wet state for a long time, the wet surface is easy to absorb dust. After a long time, the pollutants penetrate into the micro pores of the stone, and when the water is dry, it will leave the mark of water spots. In addition, when some liquid substances, such as glue, pollutants and inferior protective agents, penetrate into the pores of stone, they will also form marks similar to water spots.
In short, this kind of water spot is similar to the imprint of water spot. Strictly speaking, it is not a real water spot, but a "false water spot".