The Uses of Buffing and Polishing in Electroplating

Objects that are made of metal, or plated with metal, can be maintained and cared for with buffing and polishing.

Many people believe that the two terms are interchangeable, but they are slightly different processes; polishing is done with an abrasive that is mounted on a stationary wheel, whereas buffing is done with a hand-held abrasive. The term “polished” is often used to describe a bright, mirror-like finish, but in reality, both processes are utilized to create such an effect.

Polishing is used to achieve a variety of effects: rust removal, fixing small imperfections, etc. Polishing usually starts with a rough abrasive, then finer and finer ones, until the desired effect has been achieved. The smoothness of a polished surface is actually an optical illusion; even the finest abrasives still leave imperceptible scratches. Carbon and alloy steel, iron, and nonferrous alloys are some abrasives which are typically used on strong metals; for hard and brittle substances, or metals with low tensile strength, silicon carbide abrasives are typically used.

Abrasives which are too rough will damage the item’s surface, so the abrasive material must be chosen with caution. The abrasive is typically mounted on a polishing wheel, which can be made of wood, canvas, plastic, or a variety of other materials. Wax and kerosene are lubricants which are sometimes used during the polishing process, but the metal must be thoroughly cleaned afterward, particularly if electroplating will be done.

Items that will eventually be plated or painted are often pretreated with polishing, often in conjunction with other pretreatment methods, such as stripping, soldering, bead blasting, surface repairs, and various other treatments.

For metals such as brass and stainless steel, which usually look great after just polishing, it is sometimes a stand-alone treatment, or a step before the application of a clear-coat or lacquer. Lacquer is sometimes a better choice because lacquered items tend to require less ongoing maintenance than objects which were simply polished. If electroplating is the desired finish, this step typically follows the polishing process.

Polishing is a great pretreatment for plating because if the substrate isn’t properly prepared, the plating won’t adhere well, and therefore it will chip, crack or flake.

Often confused with polishing, buffing is a similar process used to achieve a slightly different result. Buffing wheels, also called mops, are made from bleached or unbleached wool or cotton. Buffing can be performed using one of two methods: cut-motion, and color-motion.

The former creates a uniform, semi-bright finish; it is done by moving the piece against the buffing wheel’s motion, using medium to hard pressure. Color motion, conversely, is achieved by moving the piece with the wheel, using light to medium pressure.

This process is intended to create an ultra-bright, very shiny finish. Unlike polishing, buffing is usually the last step in the finishing process.