What is Involved in Brass Plating?

Brass plating is the process of depositing a thin layer of brass onto the surface of a metallic object. This process is performed in a chemical bath that is charged with electricity. The thickness and the quality of the brass plating is determined by the length of time in the bath, the chemicals used, and the configuration of the tank.

The process that applies brass plating to an object is known as electroplating. In this process, the substrate — the metal object or surface upon which the brass plating will be applied — and a source of brass are submerged in a chemical bath. Electricity enters the system through the brass and leaves through the substrate. It carries particles of brass through the solution, towards the substrate. Once these particles reach the substrate, they settle on the surface and bind to it.

The composition of the chemical bath that the brass is submerged in is significant. Brass plating is almost always done in a cyanide solution. Though there are other chemicals that can be used, most companies continue to use cyanide because it reacts well with the brass.

The substrate material and the brass are kept in the electroplating tank while the brass plate grows. It can take anywhere from a few hours to a few days or weeks to create a layer of brass plating on a substrate. The length of time that the process takes depends on the desired thickness of the final product.

The temperature of the chemical bath also influences the time it takes for the brass plating to grow. The optimal temperature range is between 95 and 105 degrees Fahrenheit (35 and 40.5 degrees Celsius.) A plate grown at 75 degrees Fahrenheit (24 degrees Celsius) will take about twice as long to grow as one grown within the optimal temperature range.

There are different types of containers that can be used for brass plating, the most common being barrels and tanks. Barrel electroplating is useful for small objects which must be free to tumble around. The barrel is rotated throughout the process, which creates an even brass surface on all sides of the substrate. Tank electroplating is used more often with large sheets of metal. In tank electroplating, the substrate is lowered into the tank where the plating is deposited evenly on the flat surface of the substrate.