Stainless Steel Polishing Guide

Stainless steel is used widely by various industries, including for automotive parts and systems, shipping containers, building interiors and exteriors, surgical tools, kitchen cutlery and cookware, household appliances, medical implants, aircraft components, and much more. Durable and aesthetically pleasing, stainless steel resists corrosion, withstands heat, and is chemical-resistant. It’s also an extremely tough material, though it’s not impervious to the effects of time, which makes polishing stainless steel an important factor for upkeep.

Benefits of Polished Stainless Steel

Although well-known for its distinctive sheen, stainless steel can lose its luster with age. Yet polishing stainless steel not only helps keep it looking good, but it also has other benefits as well. The main benefits of polishing stainless steel are:

• Aesthetics: Polishing improves the metal’s surface quality, helping keep stainless steel looking lustrous and, when combined with buffing, it leads to mirror-like finishes.

• Reduces corrosion: Polishing helps reduce the number and size of crevices in metal that encourage rust.

• Removes contaminants: Polishing stainless steel removes contaminants from the surface, even if they’re invisible to the naked eye, which is undesirable for certain applications.

In metallurgy, metals often are polished to enable better observation of their crystalline structures, defects, and discontinuities under a microscope.

Methods of Polishing Stainless Steel

There are multiple ways in which to polish stainless steel, with the easiest method simply to apply abrasives by hand. This also tends to be the most inefficient and can cause inconsistent quality, especially when this method is used at scale. Additionally, if the steel is already dented or scratched it will require treatment, otherwise it will end up highlighting the metal’s imperfections. The types of tools and techniques used will ultimately depend on the kind of finish required.

The right equipment matters when seeking a professional finish for stainless steel. It needs to maintain a constant speed, while the abrasive used requires it keep a certain coarseness to effectively polish the steel. The type and extent of the project also help determine the equipment needed. A drill or other handheld grinding tool may suffice for smaller jobs, while larger projects could require a grinder with a polishing wheel. For truly largescale polishing of stainless steel, custom machinery may be necessary for automating the process. The following are common finishes for polished stainless steel:

• Mill or Matte Finish

An unpretentious finish, it requires less time, effort, and expense than others. To create a smoother look, mill finishes normally look somewhat incomplete, though they can be used as a starting point for a long process to produce a more attractive appearance. It is often used for practical applications like kitchen sinks or workbenches. To achieve a matte finish. the steel is rolled through special dies or rollers.

• Brushed Finish

Polishing stainless steel through brushing produces decorative patterns made up of delicate parallel lines. Without the typical reflective sheen for which stainless steel is known, it works well in areas where the metal will be exposed to bright indoor lights or lots of sunshine. Often used for kitchen appliances, its downside involves reducing the steel’s resistance to corrosion, depending on the application, rust-proofing may be advisable. Brushed finishes require a high-grade abrasive to make the lines uniform.

• Mirror Finish

A highly reflective finish, it achieves the look for which stainless steel is best known. It works great to hide welded metal and makes cleaning easier. Polishing stainless steel to attain a mirror finish requires a wheel or at least a 320-grit belt.

• Gloss Finish

Polishing stainless steel to a gloss finish will improve corrosion resistance, as it smooths crevices where rust can collect. Its chrome-like shine is perfect for automotive parts and requires the surface to be adequately prepared. Using a high-quality buffing compound and a grinder with a polishing wheel, it can also achieve a mirror-like shine after buffing.