The patina sculpture surface copper (Bronze/Brass ) or copper thermal coloring, also known as patina color, is modeled after an antique. That is to use chemical, electrolytic, physical, mechanical, and heat treatment methods. A film, coating, or coating that produces a variety of colors for the sculpture surface. Patina’s method is more. The appellation is also different. Often depending on the means of treatment and color source for bronze sculpture. Generally can be divided into coating (including spraying) thermal coloring, chemical coloring, electrolysis coloring, electroless plating, electroplating coloring, vacuum coloring, vacuum plating gold, and gold coloring technology. Among, the most commonly used are chemical coloring, dyeing, and heat treatment coloring for bronze sculpture. The traditional coloring methods are many. Especially in copper and copper alloy artworks are more widely used.
1>Pre-patina treatment for copper(Bronze/Brass) and copper(Bronze/Brass) alloy castings
In order to ensure that the copper(Bronze/Brass) sculpture surface can form a uniform color, good combination, and strong corrosion-resistance coloring layer. Before that, the surface of the copper(Bronze/Brass) sculpture must be pretreated with oil removal, erosion and rust removal, polishing copper (bronze/brass), and so on. There are a variety of oil removal methods, which generally can be selected according to the appropriate conditions and the size of the copper(Bronze/Brass) sculpture.
1-1>Wipe and remove oil: use a brush or cloth dipped in detergent, washing powder, lime slurry, magnesium oxide, and other degreasing substances to wipe the oil on the copper (Bronze/Brass) surface of the copper(Bronze/Brass) sculpture. It is mainly used for the deoiling of copper(Bronze/Brass ) sculptures with large volumes, complex shapes, and difficult to be processed by other methods.
1-2>Drum oil removal: put the copper(Bronze/Brass) sculpture into the drum of the polishing machine, and add appropriate abrasive and oil removal. Suitable for large batches, and small sizes, not easy to deform art casting oil removal.
1-3>Ultrasonic oil removal: it can remove the oil in the fine hole and the hole, and the metal corrosion on the surface of the copper(Bronze/Brass ) sculpture is small. Suitable for oil removal of small art castings.
1-4>Sulfuric acid method: Sulfuric acid can remove the oxide and rust on the surface of the copper(Bronze/Brass ) sculpture.
1-5> Etching or pickling process(Chemical coloring is the most common sculpture surface decoration method for copper sculpture and copper alloy).
1-5-1> Sulfuric acid method for sculpture surface: Sulfuric acid can remove the oxide scale and rust on the surface of the copper(Bronze/Brass ) sculpture.
Firstly, pour water into a large hard glass container. Secondly, sulfuric acid is slowly into the water (equivalent to the amount of water). Dissolve the sulfuric acid solution to remove the oxide scale. It must be washed with clean water. The etching time is about 30 seconds. If the production of gold, silver, and other different sculpture copper(Bronze/Brass) sculpture, need to prepare different acids. If the same acid solution is used for a long time, the concentration of the liquid will decrease. So the solution must be remodeled frequently. Copper etching can be used to brush the copper(Bronze/Brass) sculpture with a metal brush. Wash dilute sulfuric acid with clean water and dry it.
1-5-2:Preparation of nitric acid solution: the same steps as the production of sulfuric acid solution.
Our handlers can not be rapidly poured and do not let the water directly touch the sulfuric acid. Because sulfuric acid spatters easily cause scalds or spray on the clothes will burn holes in the solution for handlers. It can burn the skin. So, handlers hand sure to use rubber gloves to protect themselves and handle with extra care and can not touch the liquid.
2> Cold or thermal colored for copper (Bronze/Brass ) sculpture and copper alloy castings
The cold coloring reaction is slow, and the film generated is stronger. Thermal coloring reaction is fast, and the film is thicker, but not strong. So Aongking is used to dilute the concentration of the coloring liquid to make the color layer strong and durable.
2-1> Cast patina sculpture (Bronze/Brass ) chemical coloring process (one of the cold coloring methods of copper sculpture):
Aongking worker first uses sandpaper to rub the surface of the patina sculpture (Bronze/Brass ). They are pickled with dilute sulfuric acid. Scrub it with a metal brush. Then wash the dilute sulfuric acid with clean water. The relief is then air-dried (scrubbed with sodium sulfide (crystals) several times. Make the copper skin black, and then naturally dry. Make the effect simple and dignified. Then use the metal cleaning ball to scrub the high point of the patina sculpture (Bronze/Brass ). So as to polish it to enhance the sense of layers of the patina sculpture (Bronze/Brass ), and then waxing anti-corrosion or spraying transparent paint and other post-processing