Text: Xinglan Shi said
Edited |
The Eastern Han Dynasty hollow dragon pattern copper furnace in the collection of Juye County Museum was unearthed in December 2011 on the south side of Jinshan Mountain, Dushan Town, Juye County, Shandong Province.
The artifact is exquisitely ornamented, exquisitely structured, and specially cast, and there is no other archaeological information and cultural relics reference because it has not undergone formal archaeological excavation.
This copper furnace has a peculiar shape, the body is composed of two parts, the upper part is a rectangular hollow stove, and the lower part is the furnace body support structure, which is composed of three round wheels and trays. The artifact is a national first-class cultural relic and has important historical, cultural and artistic value.
Due to the factors of the cultural relics themselves and the influence of the preservation environment, there are a variety of diseases in this copper furnace, mainly including fracture, mineralization, pitting corrosion, induration, mutilation, soil attachment, etc.
Before the implementation of protection and restoration, it is necessary to observe and analyze the structure and diseases of the copper furnace. The connection between the copper furnace axle and the chassis has rust and mineralization falling off. The top small copper pot is missing one.
The rear wheel and shaft cannot rotate due to corrosion, and the rust on the surface of the middle part of the long shaft appears to peel off, and there is light green rust under the peeling layer, and there are slight tumors on the surface of the whole body on both sides.
The connection between the left side and the chassis is suspected to be corroded by iron and soil, and the hub and shaft on the right side are also suspected to be severely corroded with iron, and there is mineralization.
The junction between the front wheel and the head of the beast is seriously corroded and mineralized, and there are a large number of suspected iron and soil combinations. There is a large amount of suspected iron soil rust at the junction between the head and the chassis.
There is a large amount of harmful rust and slight protrusion at the junction between the outside of the chassis and the axle, and according to previous repair experience, chloride ions may be present under the corroded layer. There are unevenly distributed induration and soil attachments on the surface of the whole body, and there are spot mineralization locally, and the dragon pattern on the left side is more serious in the lower right corner.
Copper furnace detection and analysis
According to the condition of the corrosion on the surface of the copper furnace, different colors of corrosion were extracted from the axle, the bottom of the furnace and the head of the animal, and a total of 10 samples were analyzed for phase analysis.
The analysis results of different colors of rust on the surface of each part of the copper furnace are complex, and the harmless rust components mainly include copper salts such as malachite (basic copper carbonate) and copper sulfate, as well as lead ore (lead carbonate) and silica. It is worth noting that hazardous rust products such as cupalrite and parachlorochlorite were found in samples 1, 2 and 9.
The results of XRD analysis showed that the basic copper chloride (cupocite, parachlorochlorite) in the light green powdery rust belonged to the harmful rust components, which could easily lead to the spread of powdery rust on the surface of the utensils in a humid environment, and then make the ornaments peeling off and the inscriptions blurred, and in severe cases, the utensils were pulverized, paralyzed, and completely destroyed.
The chloride titration experiment in the preliminary protection research work also verified the presence of chlorine in the corrosive, so chlorine removal is one of the key points of protection and restoration of this copper furnace.
The white mixed with green powdery adhesion found below the left side of the furnace body is mainly composed of lead carbonate (white lead ore), so it is speculated that the copper furnace base may contain lead, and lead salts may appear in the rust due to corrosion.
The texture of lead carbonate is loose, and the color has a certain similarity with powdery rust, so attention should be paid to distinguishing it when cleaning and removing rust, and the matrix of lead carbonate powder has been partially penetrated and reinforced.
In addition, iron oxides were found in the yellow-brown rust, and the distribution of this brown rust was relatively concentrated, so attention should be paid to observing and analyzing the materials of other components of the copper furnace.
China is one of the four major ancient civilizations in the world, with a long history of civilization and a splendid ancient culture. The smelting and use of bronze ware is an important page in the long ancient civilization of the mainland, and the Shang, Western Zhou and Spring and Autumn periods are also called the "Bronze Age" by historians.
However, some precious cultural relics have been handed down to this day, and there are different degrees of damage and disease, and it is urgent for professionals to restore and protect them. Taking the restoration process of a bronze in the Western Zhou Dynasty as an example, this paper briefly expounds the general steps, methods and precautions of bronze restoration.
It aims to emphasize that the restoration of bronzes should follow the principle of "protection first, rescue first", adhering to the concept of "repairing the old as the old", carrying forward the spirit of craftsmen, and repairing every cultural relic with heart.
China is a country with an ancient civilization, a vast land and a long history, and the Chinese nation has created a rich scientific civilization and artistic civilization in the long course of history, and the cultural relics preserved on the ground and underground are not only of great variety, but also extremely rich in quantity.
The bronze is 53.5 centimeters high, 22 centimeters in diameter, and the mouth, shoulders, and abdomen of the body are cracked and deformed to varying degrees. Among them, the abdominal damage is more serious, and a total of 9 fragments can be found at present, and some of them are found to be missing after splicing, which need to be supplemented later. In addition, there are several fine cracks in the body and varying degrees of corrosion.
Remediation process
Before the restoration of cultural relics, we have to take pictures, measure, weigh and other work, and make detailed records. According to the current state of preservation of the cultural relics and the degree of corrosion, experts in related fields have discussed and formulated a restoration plan suitable for the artifact.
Before the implementation of the restoration work, it is necessary to establish a restoration file and record the relevant information, including the methods and materials used in the restoration process, so as to provide a basis for future cultural relics protection and research.
Cleaning, mainly bronze mud removal, rust removal two aspects of work. Use a brown brush to remove the dust on the surface of the body, and then wash it with distilled water. The use of distilled water for cleaning can effectively reduce the erosion of copper ware by chloride ions in tap water.
Put the body fragments into the ultrasonic cleaning machine for repeated cleaning, and use the ultrasonic oscillation principle to quickly clean and remove the floating rust on the surface. Some parts with severe rust are treated with an ultrasonic scaler. After treatment, the bronze body decoration is clear, and the fracture is clean and tidy, laying a good foundation for the next step.
Shaping and welding. Due to the different degrees of deformation of the body and fragments, our first task is to reshape it. Before the utensils are shaped, the fragments should be heated, commonly known as "de-fire" treatment.
Because the unearthed bronzes are old and their structure is relatively fragile, direct percussion and shaping often cause secondary damage. After the "de-fire" treatment, the toughness of the metal is increased, and the probability of fragment damage in the shaping and knocking process is effectively reduced.
It is worth noting that the control of shaping strength is particularly important: the force is too light to achieve the shaping effect; If the force is too heavy, it will cause new damage to the cultural relics. Therefore, plastic surgery work needs to be completed by comrades with certain work experience.
In addition, in the work, we should also pay attention to the comparison with the cultural relics to prevent overcorrection. For the body part, we use U-shaped pliers, small jacks and other tools to correct the internal and external functions in batches. After several reshapings, the bronze gradually regained its original shape.
The welding of bronze cultural relics is still a more traditional soldering method. The advantage of this method is that the weld strength is good and it is easy to operate. At the same time, the melting point of solder is low, which is easy to adjust during the soldering process, and conforms to the principle of reversible operation in the restoration of cultural relics.
Due to the thick wall of the bronze revelry, the weld at the fracture should be polished before welding, and the weld on both sides should be polished obliquely by using the power tool to make it present a "V" shape, which can effectively increase the contact area of the solder and enhance the welding firmness.
When welding, we from the edge of the mouth to the shoulder, the abdomen in turn, on the consistent fragments to do a good mark, after many times of welding, we have been the body cracking and fragments of all the processing, the bronze body of the body is basically formed.
After the soldering is completed, the protruding lead and tin should be polished to prepare for the next step of film turning and replenishment.
Turning over the film and supplementing. The bronze belly and ears are partially missing, and these need to be replaced. Because the pattern and shape of the bronze body are designed with symmetrical composition, gypsum can be used to turn the film and make up for the defects according to the symmetrical pattern.
We used plaster to turn the relatively intact side of the bronze to make the whole film, and in the process of turning the mold, in addition to the plaster, we also added brown silk to enhance the strength of the mold. After the film is turned on one side of the outer wall, we roll out the clay in preparation for the production of the "inner mold".
Lubricating oil is used in the production process to increase the plasticity of the clay. At the same time, the thickness of the clay should be appropriate. The clay is evenly applied to the inner wall of the gypsum mold, and this thickness is basically the thickness of the carcass made by pouring in the later stage.
Supplement material, use babbitt. This material has the advantages of good plasticity and high strength, according to the previously made mold, the pasteur is financialized and poured into the gypsum mold to obtain the parts that need to be supplemented, and it is placed on the body by welding.
After filling the gaps, all the gaps on the body of the vessel should be sealed and reinforced with marble glue, and special attention should be paid to the consistency of the curvature and flatness of the repair part and the body, and the ornamentation should be connected to highlight the integrity of the bronze body.
Old. Before aging, the solder spots are treated with ferric chloride solvent, which can effectively remove the bright spots of the tin dots and prepare them for the next coloring step.
At present, the aging and coloring of bronze cultural relics is mainly based on the combination of mineral pigments, shellac and alcohol, and the corresponding colors are modulated according to the background color of the utensils.
Use brushes and other tools of different sizes to paint, brush, play, point, rub and other techniques to color and worn. In the order from the bottom to the outside, the colors are made layer by layer. When making rust color, it should be light but not deep, not in one step, and it should be repeated many times.
This will give the rust a layered look. In addition, in the process of coloring, the matting agent can also be used to treat the part to remove the excess bright light, so as to achieve the effect of adapting to the same color around the original artifact, and strive to maintain a high degree of consistency with the original artifact after aging, giving the audience a sense of beauty.
epilogue
Cultural relics are the testimony of thousands of years of Chinese civilization, and they are not renewable, let alone replaced. The protection and restoration of cultural relics can not only prolong the life of broken and corroded cultural relics, but also extend their scientific, historical and artistic value.
Restoration is like a doctor treating a patient, and we need to implement protection measures according to the characteristics of the disease. Bronze restoration is an important part of the protection of cultural relics, with the development of science and technology, more new technologies and new materials will be applied in the protection and restoration of cultural relics.
The experience inheritance of the older generation of cultural relics restoration workers, modern restoration technology and restoration concepts are very worthy of learning and reference from our younger generation of cultural heritage conservation workers.
Only by continuous theoretical study and practical operation cognition can we master the key technical points in the restoration process more proficiently and continuously improve our professional and technical level.
Following the principle of "protection first, rescue first", adhering to the concept of "repairing the old as the old", carrying forward the "craftsman spirit", repairing every cultural relic with heart, and keeping more cultural relics away from rust and disease, is the goal that our cultural preservation workers diligently pursue.
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