How to Judge Antique bronze Mirrors?

Copper in the atmosphere, sea water and certain non-oxidizing acids (hydrochloric acid, sulfuric acid), alkali, salt solution and various organic acids (acetic acid, citric acid), good corrosion resistance for the chemical industry. In addition, copper has good weldability, the cold, made of thermoplastic processing of a variety of semi-finished and finished products. In the 1970s, copper production of more than the total output of other types of copper alloy. Bronze and zinc as the main alloying element in copper alloy, and often has yellow and named. The beautiful bronze color, process and mechanical properties, electrical conductivity and high thermal conductivity, corrosion resistance in the atmosphere, freshwater and seawater, cutting and polishing, good weldability and cheap. There are ridges on the belly and the feet of the bronze. Conductivity, thermal conductivity components, corrosion resistance used in the production structure, the elastic element, household hardware and decorative materials, widely used.
In general, the cutting performance of the bronze is superior to copper (copper is easy to stick the knife); in the non-cutting, the deformation resistance of the copper smaller, easier to shape. Copper is pure copper, pure copper color is orange or red roses, but exposed in the air will be oxidized to the purple, so called copper. The inscriptions are alike in the belly and on the bronze.  Bronze is a Cu-Zn alloy, copper 80%. Hardness, but poor electrical conductivity, thermal conductivity than copper. Copper and bronze welding method; Gas welding, manual carbon arc welding, manual arc welding and manual argon arc welding copper (ie, commonly known as industrial pure copper) method, an automatic welding of large structures.
Welding copper is the most commonly used is the butt joints, lap joints and T joints to minimize use. Welding can be two types of wire, a wire containing deoxy elements, such as wire 201, 202; another purple copper and base metal cutting, the use of gas agent 301 as flux. Welding copper should be used for the neutral flame. The overall bronze looks refined and gorgeous. Manual arc welding of copper; Copper electrodes in manual arc welding of copper 107, welding core of copper (T2, T3,). The edge of the weld should be cleaned before welding. Weldment thickness greater than 4 mm before welding, preheating, preheating temperature of about 400 ~ 500 ℃. 107 electrode with copper welding, power should be used DCRP.
Should be used short-arc welding, the electrodes are not suitable for lateral oscillation. Welding rod for reciprocating linear movement can improve the forming of the weld. Long weld gradually retreat welding method. Welding speed should be faster. Multi-pass welding, must be thoroughly cleaned of slag layer. Welding should be carried out in a well ventilated place to prevent copper poisoning. Flat mallet percussion weld after welding application, eliminate stress and improve weld quality. A noble Muyang family produced this ding acting as sacrificial bronze dragon to memory Fuxin.  Manual argon arc in copper wire used in wire 201 (a special copper wire) and wire 202 is also used copper wire, such as the T2. Response to the edge of the workpiece welding and wire surface oxide film, oil, dirt must be clean to avoid porosity, slag, and other defects before welding. Clean-up methods of mechanical cleaning and chemical clean-up method.