How To Polish Stainless Steel

Many industries employ stainless steel, including furniture, appliances, automotive, and knife manufacturing. Stainless steel is not only visually pleasing but also strong, resistant to chemicals and corrosion, and unaffected by high temperatures. But over time, it can fade, which is why maintaining it with polishing is essential.

In this tutorial, the Benchmark Abrasives team provides instructions on how to polish stainless steel so that it looks as beautiful as it performs.

PURPOSE OF STAINLESS STEEL POLISHING

Stainless steel's characteristic shine may diminish with age. There are other advantages to polishing stainless steel in addition to maintaining its aesthetic appeal. Polishing stainless steel has the following benefits:

• AESTHETICS: Polishing maintains the metal's glossy appearance and improves its surface quality when paired with buffing. 
• CORROSION REDUCTION: Polishing metals lessens the quantity and size of rust-promoting fissures. 
• REMOVAL OF CONTAMINANTS: Polishing stainless steel cleans the surface of even imperceptible impurities. In some applications, these quality flaws might not be desired.

WHAT TYPE OF FINISH DO YOU WANT?

Generally speaking, the type of finish you want will dictate the process and equipment you employ to polish your stainless steel surfaces and components. Below is an overview of the most popular finishing options.

• BRUSHED FINISH
  

Brushing stainless steel creates delicate parallel lines to create ornamental designs. Because it doesn't have the typical reflecting sheen of stainless steel, it works well in regions exposed to bright indoor lighting or lots of sunlight. However, depending on the use, it can lessen the steel's resistance to corrosion; thus, rustproofing can be necessary. A high-grade abrasive is needed on brushed finishes to ensure uniformity in the lines.

• GLOSSY FINISH
  

By smoothing out rust-collecting crevices, polishing stainless steel to a gloss surface increases its resistance to corrosion. Its chrome-like sheen makes it ideal for automobile parts, but a well-prepared surface is required. High-quality buffing compound and a grinder fitted with a polishing wheel can also be used to buff the surface to a mirror-like sheen.

• MATTE FINISH
  

Matte finishes are less showy and require less money, time, and effort to obtain than other finishes. They are frequently used for functional items like workbenches and sinks in bathrooms or kitchens. Generally, one or two buffing levels—240 grit and 300 or 400 grit—will yield a matte finish.

• MIRROR FINISH
  

This extremely reflective polish gives stainless steel its most recognizable appearance. It conceals welded metal and facilitates cleaning. To attain a mirror-like shine on stainless steel, buffing wheels equipped with extremely fine-grit abrasive belts or compounds are required.

DOES STAINLESS STEEL NEED TO BE SANDED PRIOR TO POLISHING?

Not always, but occasionally. A polishing compound can be used to address small surface flaws on stainless steel surfaces. However, deep scratches will require sanding down.

Find the most severe imperfection on the surface to assess whether sanding is required. To buff it, use the least abrasive grit you have. It will usually be a combination of 400 grit. If the scratch is still noticeable, try again with a slightly rougher grit, like a 320-grit metal polishing compound. Examine and clean the surface once again. You should sand it if you can still see the scratch.

STAINLESS STEEL MACHINE POLISHING

Below are the tools and procedures for using an angle or bench grinder to achieve a smooth finish.

TYPES OF EQUIPMENT:

• Angle grinder or bench grinder
• Buffer and buffing pad
• Abrasive (sandpaper)
• Acetone or alcohol
• Soft sponges or clean clothes
• Polishing compound
• White vinegar (optional)

STEP 1: WASH AND PREP THE STAINLESS STEEL

Stainless steel surfaces need to be thoroughly cleaned before polishing. Foreign objects have the potential to mar and damage the surface, making it appear worse rather than better. Use alcohol or acetone to get rid of any sticky residue. Next, use a soft sponge or cloth and warm, soapy water to clean the surface; avoid using steel wool or anything else that can scratch the stainless steel. Before continuing, make sure the surface is totally dry.

STEP 2: LEVEL THE SURFACE

Once you have a clean surface, remove any rough spots with 80–120 grit sandpaper (if the steel is welded, remove the bead). Take your time so as not to create a low spot by over-grinding the surface. An angle grinder is the most user-friendly equipment for larger objects; for smaller items, a bench grinder would be more suitable. Before proceeding to the following stage, make sure you clean the piece once again because any remaining impurities could impact the finished product. 

STEP 3: GENTLY SAND THE SURFACE

Once the imperfections are less noticeable, go from using the grinder to sandpaper. When working with metals that have a mill finish, you can begin with paper that is 120 grit and go up to increasingly finer grits as the surface gets smoother. Gradually work your way up from 240 grit to 400 grit, then 600 grit, and then 1200 grit. You could even go one step further and use 2000-grit sandpaper for a mirror finish.

To buff stainless steel, set your sander between 4,000 and 6,500 RPM. Take care to move the sander against any obvious scratches at a 90° angle. (Move 90° from the previous motion each time you adjust the sandpaper's grain.) You can proceed as soon as the stainless steel component has an even, satiny finish. Finish by using a gentle sponge or towel bathed in water to wipe the steel surface.

STEP 4: POLISH

Select a polishing compound made specifically for stainless steel; green rouge or white rouge are our top picks. After applying a tiny amount, work the buffer wheel slowly up and down the length of the surface. Make sure your routes overlap to prevent surface smoothing lines. Maintaining the motion of your buffer is equally crucial to avoid scorching the steel's surface.

Stainless steel can be polished to remove blemishes and defects, preventing debris from gathering in tiny voids. During the multi-step procedure, the metal's greatest aspects are recovered, and faults are gradually smoothed out. The only way to restore the surface and give it that beautiful, long-lasting mirror sheen is by buffing, which takes time.

TIPS FOR OPTIMAL POLISHING OUTCOMES

Buffing is the most crucial stage in polishing stainless steel to a mirror shine. Take your time and be careful not to overdo the compound application on the buffing wheel each time.

ADDITIONAL ADVICE

• Be gentle. You don't need to exert much pressure because you're just finishing the piece. 
• Try to keep your lines as close together and tight as possible. Avoid overlapping too much, and always work with the grain to achieve an even finish.
• Go over the piece quickly. Refrain from spending too much time on the surface. 
• Keep an ample supply of clean cloths and buffing wheels available to ensure that you can replace them anytime you switch compounds. Preventing cross-contamination is crucial when employing different abrasives. 
• Examine the piece for scratches or flaws before moving on to the next stage. 

SUGGESTIONS FOR NATURAL POLISHING

If you'd rather work with natural materials and the scratches on your stainless steel surfaces aren't too bad, you can use the following materials on the affected regions and move them about in a circular motion. Use a dry towel or a soft-bristled brush. When finished, wipe clean.

• BAKING SODA

If your stainless steel just needs a little brightness, apply a small amount of baking soda to a moist sponge or towel and use the same method as for stainless steel polish. Because baking soda has a tiny abrasiveness, make sure you work with the grain of the steel. It's an excellent choice for cleaning and polishing kitchen appliances, utensils, and surfaces because it's also safe for use around food.

• VINEGAR

Vinegar cleans stainless steel of filth, grime, and adhesive residue while remaining non-toxic. To polish stainless steel, you must dilute the vinegar with water first because applying straight vinegar to the steel would cause it to turn black.

Mix eight parts water with one part vinegar. After applying the solution, give the stainless surfaces five minutes to sit. After that, wipe with a moist cloth or rinse with cool water. Once the surfaces made of stainless steel have dried, dab them with olive oil and use a fresh cloth to clean them.

• BABY OIL AND DISH SOAP

Dish soap and water can be combined to create a mild solution for cleaning stainless steel surfaces and appliances. Use warm, soapy water to rinse their surfaces thoroughly. Once the stainless steel has cured, polish it with a thin layer of baby oil. 

CONCLUSION

Even though stainless steel is one of the hardest metals to polish, you can bring back its original brilliance. With the correct equipment and supplies, you can still achieve excellent results, no matter how big or small your job.

We have the tools at Benchmark Abrasives to help you achieve a finish you'll adore. Red Label provides premium buffing wheels, sanding discs, and buffing compounds to polish and shine stainless steel and other metals.