The characteristics of imitation of blue and white porcelain in the Yuan Dynasty: it is difficult to identify high imitation goods. If necessary, modern high-tech means should be used for auxiliary identification. However, as far as general imitation goods are concerned, as long as they master the knowledge of ancient ceramics, they can Make a clear judgment. The following is a list of common problems in the imitation of a replica. Any one of the following features must be a modern replica. (1) The porcelain tire is too white, too fine or too dense: the birth quality of the Qingdai porcelain produced by Jingdezhen is similar to that of the Song Dynasty Qingbai porcelain, except that the alumina content is about 1.5% higher than the latter, which contains trace iron. It looks white and gray. In the process of processing the raw materials of the blue-and-white porcelain in the Yuan Dynasty, except for the use of water smashing during rough processing, the rest were manually operated. It is significantly different in fineness and density compared to modern materials processed using ball mills and vacuum-lined machines. Generally, low-end and mid-range replicas are produced by using mechanical processing materials to reduce costs. The tire quality is not too white, too thin is too dense. [10] (2) There is artificially applied or sprayed iron oxide rust on the exposed part of the foot: It is generally believed in the society that the exposed parts of the blue-and-white porcelain of the Yuan Dynasty have the phenomenon of “flint redâ€, and this is used as the identification standard. In fact, the phenomenon of "Flint Red" only exists in some blue-and-white porcelains of the Yuan Dynasty, and there is a phenomenon that there is no "Flint Red" on a considerable number of ancient artifacts. A large number of experiments have proved that the "flint red" phenomenon must have two basic conditions: one is the presence of a certain amount of free iron in the body, and the other is that the body contains a sufficient amount of water when it enters the kiln. Only in this way, in the initial stage of the kiln heating, as the moisture in the body rapidly evaporates, the free iron is brought to the surface of the body to form "flint red". Generally speaking, the first condition belongs to the internal cause, which is generally possessed by the blue-and-white porcelain in the Yuan Dynasty, and the second condition is the external cause, which is not a prerequisite for the blue-and-white porcelain of the Yuan Dynasty before firing. Some utensils have been "dried" before firing, and even the "pads" used in the kiln are free of moisture. If this is the case, the phenomenon of "flint red" rarely occurs on the surface of the burner. Because the low-grade imitation of the body does not contain free iron, the imitation of the imitation of the method of smearing or spraying iron oxide rust, in fact, is intended to cover, it is significantly different from the real "flint red" and "maste bottom". (3) Smooth and unlined inner wall: The Yuan Dynasty utensils are mostly hand-drawn or de-molded, and the fingerprints and swirls tend to flow down on the inner walls of bottles and cans. If no fingerprints and swirls are found on the inner wall of the object, it is a low-grade replica produced by a modern grouting process. When we look closely at the insole of this type of device, we will find a circle of "slurry" printed on the foot. If it is a device with both ears, its ears are often hollow grouted, and there are vent holes in the concealed area below it. The grouting process was introduced to Europe from Europe after the middle of the Republic of China, and was generally used in the production of craft porcelain after the 1950s. (4) There are repairing knife marks on the inner wall: Anyone who knows the ceramics production process in Jingdezhen knows that there are two types of knives for repairing blanks. One type is called “bar knifeâ€, which is used to trim the inner wall of the object; The "plate knife" is used to trim the outer wall and the foot of the object. The appearance of "plate knife" has been at least 2,000 years old, and the "knife" was only available during the Kangxi period of the Qing Dynasty. In other words, the porcelain before Kangxi only repaired the outer wall and did not repair the inner wall. The porcelain after the middle of Kangxi began to trim the inner wall. Some imitations don't understand this, they just make it according to the catalogue, and often add snakes to trim the inner wall. (5) Those with uniform and fine line-shaped knife marks: Before the Ming Dynasty, the knives were made on the basis of the blacksmith's forging and forming, and then ground with whetstone. After the European industrial revolution, steel shovel was introduced to China. Ceramic craftsmen in Jingdezhen quickly discovered that tools made from steel boring were superior to grinding knives. The edge of the steel boring tool is sawtooth. Use it to save labor, labor and durability. As a result, this method of processing knives quickly spread in the Kangxi period of the Qing Dynasty and has been passed down to the present day. At the same time, ceramic craftsmen in Jingdezhen also invented strips of various shapes. Porcelain blanks trimmed with this tool leave a uniform and fine line of knife marks. (6) Those who are glazed over white: As the saying goes: "The clothes are the right bones." Here, "clothing" refers to the glaze of porcelain, and "bone" refers to the tire of porcelain. The enamel of the blue-and-white porcelain in the Yuan Dynasty was all white and green, especially the early products were basically the same as the glaze of the Qing Dynasty white porcelain in the Song Dynasty. The color of this transparent glaze is often related to the tire quality. During the firing process, the iron in the tire will diffuse into the glaze under the action of high temperature, and the reducing atmosphere in the kiln will make the finished glaze appear bright. The ground is blue and white. Most of the imitation products have insufficient iron content, and their glazes are not blue enough. (7) Smooth or flat glaze or thin enamel: The flatness of porcelain glaze is directly related to the glazing method. Since the blue and white porcelain of the Yuan Dynasty is made of enamel, glaze and glaze, it seems that the enamel is plump and thick, but the flatness is lacking. In particular, large objects such as glaze and glaze are used, and glazes often have "tear marks" and "brush marks". After the Qing Dynasty, Jingdezhen generally used the glaze method to glaze. The flatness of the glaze was much higher than that of the previous dynasty. Modern electric air compressors were used instead of artificial glaze, which greatly improved the production efficiency. The glazed surface is too smooth and thin, and all are modern blow glaze products. (8) The iron element in blue and white floats on the glaze table: The ancient use of "Subini blue" is a natural mineral material, the main component of which is cobalt oxide and a small amount of iron oxide. Iron and cobalt are fused together and evenly distributed. Under the action of high temperature, the iron oxide in "Suboni" will accumulate in the silicate liquid to form dark spots. They generally do not float on the surface of the glaze, forming so-called crystals, which are observed under a microscope, and are often irregularly shaped with brown spots on the underglaze. Most modern imitations are simply added iron oxide powder in domestic blue-and-white production, and are not subjected to high-temperature calcination treatment. Therefore, iron oxide cannot be uniformly fused in cobalt oxide. Under the action of high temperature, these iron oxides will Quickly float to the surface of the glaze to form crystals. Most of the slag-like spots were observed under a microscope. (9) The color of blue and white flowers is too dark or bright: compared with “Subiniqingâ€, the content of manganese is obviously higher than that of “Subiniqingâ€. The former is 60~300 times of the latter. If the manganese in the domestic green material cannot be effectively removed, it is only a case of adding iron, and the color of the blue and white will appear gray. If cobalt oxide in the chemical industry is directly used as a green material (commonly known as "blue"), its color will appear too bright. (10) The painted pattern is decorated with flaws: Observing the ornamentation is the basis of identification. Generally speaking, the imitation of the imitation goods is very close to the real thing, otherwise it can not be called "imitation", and often requires careful observation to discover the flaws. (11) The shape of the object is inconsistent with the age or process characteristics: there are two cases here. One is that the counterfeiters pursue novelty, so that the collectors can't figure it out. As the saying goes, things are rare. In the unlikely event of a recent "out of the box", it is a big "leak". The other is that the copycats don't have enough effort, and often they have more than enough energy and they are consciously and unconsciously doing the same. (12) The mouth and foot lines of the utensils are stiff or too regular: the plasticity of the ceramic raw materials processed by modern machinery is generally not as good as the raw materials prepared by the Yuan Dynasty. As far as the ceramic molding process is concerned, the popular saying in modern Jingdezhen is: three-point drawing, seven-point repairing. That is to say, the shape of the object is mainly repaired by a repairing knife. The Yuan Dynasty process is exactly the opposite. It is a seven-point drawing and a three-point repair. Some people think it is a technical problem. Actually, it is not because the plasticity of modern mud is not as good as before. Since the Yuan Dynasty mud can be pulled very thin, the upper part and the inside of the object do not need to be trimmed at all, but the lower half and the foot are simply trimmed. Therefore, the mouth and neck of the Yuan Dynasty utensils have smooth lines, and the shape is round and does not fall. The drawing of modern imitation goods is very thick, not only to repair the upper part, but also to repair the inner wall. Therefore, the lines are hard and regular, and the knife marks are numerous. (13) The ratio of volume to weight of the utensils is obviously extraordinary: the object is too light or too heavy to indicate that there is a problem, and those who are too light often use the "grouting" molding process. The wall of the hand-drawn blank forming process is thin and thick. The former is as thick as the upper and lower sides. If the thickness of the mouth of the object is appropriate, the lower part is thin, and generally not easy to detect, only by weight. Overweight people are often due to the poor plasticity of the mud. The poor plasticity of the clay will make the forming of the blank difficult, thin, and the type is not accurate, thick and heavy. It is the wall thickness and the authentic type of the imitation, it will also appear to be heavier than the real product, because the density of the imitation tire is generally higher than the real product. (14) The molding process is inconsistent with the characteristics of the times: the “grouting†mentioned above is only one of the molding processes. There was a case of blue and white strips, which was made of solid sheets and glued to Jingdezhen. The collector only said that it is the authenticity of the Yuan Dynasty according to the blue pattern. The truth is that it is a national treasure. Regrettably, the Yuan Dynasty did not have the molding process of “setting inâ€, but it was only in Jingdezhen in the Qing Dynasty that the “inlaid living†process was adopted. (15) The characteristics of the pad burning process are inconsistent: At present, Jingdezhen generally uses petroleum liquefied steam kiln to burn porcelain. In order to prevent the object from sticking to the silicon carbide slab, it is necessary to sprinkle quartz sand or alumina powder between the two. Carefully observe the foot ring of the utensil. If the above two materials are adhered to it and they are very strong, they must be modern replicas. Not only the Yuan blue and white, but also the Ming and Qing porcelain. In ancient times, quartz sand and alumina powder were not used as litter. (16) Those who have obvious traces of work on the surface: If you want to make imitation goods sway through the city, you can't do without the "old" process. The old traces of human work are fundamentally different from the natural appearance of ancient ceramics. (17) Using X-ray fluorescence detection, the indicator element exceeds the standard: the brightness of the ceramic glaze will gradually decrease with the passage of time, which is due to the “devitrification†of the enamel itself. In order to reduce the brightness of imitation glaze, adding zinc, zirconium, titanium and other oxides to the glaze as a matting agent is one of the common means of modern imitation. X-ray fluorescence analysis can be used to detect the content of various elements in the tire and glaze without damage. If one of the above elements exceeds the standard, it is a modern imitation. (18) Using spectral analysis, the enamel aging coefficient is below 0.10: enamel itself will produce “devitrification†phenomenon over time, also known as aging. The aging coefficient below 0.10 must be a modern imitation.
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