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How to Polish Aluminum

Knowing how to polish aluminum can help you put the finishing touches on your own projects for that extra shine. Plus, this experience can round out your skill set to increase your job marketability.

At the same time, the process of polishing aluminum can seem like it requires a lot of technical knowledge. With the right guide and set of tools, you can easily polish aluminum with no prior experience. Our guide will show you how to polish aluminum, whether you choose to do it by hand or with the right power tools.

Key Takeaways:

• Polishing aluminum by hand is more cost-effective and efficient in most cases but requires more time.
• Power tools achieve a mirror-like finish faster, albeit with more technique involved.
• Preparing your aluminum piece for buffing is critical to the final look and feel of your aluminum piece. It’s the difference between a dull haze and a chrome-like mirror finish.
• Seal your polished aluminum to protect it from tarnishing with a sealant or specific wax.

Applications

Aluminum is a porous, non-ferrous metal that is prone to discoloration and oxidizing. Dirt and debris collect in the pores and can cause a tarnished look. By polishing aluminum, you are effectively cleaning out those pores and minimizing them to the point where the surface looks smooth.

Aluminum is used for many applications, including:

• Bakeware
• Small mechanical parts
• Boats
• Trailers
• Wheels
• Exhaust pipes
• Fasteners

This list is certainly not exhaustive. Aluminum parts, in many stages, surround us in our daily lives. You might be surprised to know how much aluminum you encounter on a daily basis.

It’s important to note that only bare aluminum can be buffed. If you are polishing aluminum that is otherwise finished, you can potentially ruin/remove that finish. Conversely, polishing bare aluminum can help prevent rust and corrosion so your aluminum piece lasts longer and looks better.

Polishing Methods

How do you polish aluminum? There are two distinct polishing methods: by hand or with power tools. Choosing between these methods will largely depend on:

• How much time you have
• How much effort you’re willing to put in
• The size of the aluminum parts
• What materials you have available to you
• What level of shine you’re looking for

Alternatively, you can tumble your aluminum parts in order to shine them. This particular method, as we’ll discuss, works in a limited number of applications. However, it can be much easier to tumble certain aluminum parts, rather than polish them by hand or with power tools.

By Hand

Knowing how to polish aluminum to a mirror finish by hand takes time. This method is best for aluminum with little to no scratches or imperfections. It’s also a safer and more efficient alternative to polishing aluminum with large power tools, especially if you’re working with smaller parts.

Many people start out by learning how to polish aluminum by hand. When working with your hands, you’re able to get more involved in the process. The feel of the polish against the metal can give you tactical feedback to guide you in the process.

Polishing aluminum by hand can also work well for one-time applications. For example, if you already polished your aluminum wheels with power tools, you might polish them again by hand later down the road. This helps to keep that polished shine fresh so you don’t have to break out the power tools again.

Power Tools

On the other hand, knowing how to polish aluminum to mirror finish levels is easiest with power tools. This method also comes in handy when time is a limiting factor and/or you have a large surface area to polish.

If you know how to polish aluminum with a buffer, you can achieve a more uniform polish. The machine will rotate at a constant speed, unlike your hands. If you know how to polish aluminum to mirror finish by hand, you also know that it’s much easier to accomplish with a machine. The buffer will generate enough heat, along with pressure and movement, to obtain the results you want.

There are a few basic power tools involved in the process of how to shine up aluminum, including:

• Orbital sander
• Rotary buffer
• Benchtop buffer
• Angle grinder
• Grinding flap disc

Depending on the process you choose of how to polish raw aluminum, you may need one or more of the tools above. At the very least, you’ll need a sanding power tool, as well as one that can buff the aluminum to the desired finish.

Tumbling

If you’re wondering how to polish cast aluminum, a vibratory finishing machine, also known as a tumbler, is your answer. This machine uses tumbling media to polish small and medium-sized parts to a mirror finish.

Most tumblers contain a particular type of media that achieves the effect they want. For example, to know how to polish aluminum to look like chrome, you’ve got to work through the media types just like you would with sandpaper. Moving from harsh grit/media to a finer grit/media will greatly affect the final look of your aluminum parts once they’re through the polishing process.

Plastic media gets rid of machining marks and imperfections. The cutting grades vary from ultra-fine and light to medium and fast. You can also use porcelain tumbling media. This material will polish and/or burnish small aluminum parts to achieve a smooth, shiny surface.

Homemade Aluminum Polish

There are a number of aluminum polish products available for purchase, but you can also make your own polish at home. These homemade polishes are best used for small and/or light scratches and will of course require application by hand.

Here are the basic steps in creating and applying your homemade aluminum polish:

1. Mix a liquid and a solid to form a paste.
2. Apply the paste to your aluminum piece with a microfiber cloth.
3. Work the polish paste around the aluminum and then wipe it off with a clean rag.
4. If necessary, buff the aluminum with a separate clean cloth to achieve a better shine.

You can use any of the following to polish your aluminum:

• Vinegar and salt
• Cream of tartar and water
• Baking soda and water
• Toothpaste
• Lemon juice
• Olive oil

You may find that with each blend, you get different results. Take notes of which work best for your projects.

Safety Best Practices

Staying safe while you work is just as critical as knowing how to polish aluminum at home. You should always have protective eyewear on, as well as an apron or clothing you don’t care about getting dirty. Work in a well-ventilated area with lots of light so you can see what you’re doing.

When you are sanding, you should also wear a respirator. This will protect your lungs from harmful particles that can cause respiratory problems.

You may also want to wear gloves in order to protect your hands when you polish. The polish can turn black or dirty very quickly, and it can also be hard to get off your hands once you’re finished.

If you are working with aluminum that you plan on using with food, you’ll want to use only food-safe polish. Cream of tartar and water mixed into a paste can be a great alternative that will still get the job done.

How to Polish Aluminum

There are 4 main processes: cleaning, sanding, buffing, and maintaining.

Clean

It’s important to know how to clean and polish aluminum. Preparing your aluminum piece for polishing requires readying the surface for the polish. What most people don’t realize is that the steps you take in cleaning and sanding your aluminum have more influence over the final product than the polishing step itself.

The basics of cleaning your aluminum piece before you sand it include:

• Using a degreaser, solvent, or stripper to remove any surface impurities, including grease, wax, paint, etc.
• Washing the piece with soap and water and allowing it to dry
• Applying a specific metal-cleaning product that preps the surface for sanding and polishing
• Scrubbing away stubborn grit with a wire brush

A clean aluminum piece can now be sanded to smooth down any imperfections and create a desirable finish.

Sand

The process of knowing how to polish oxidized aluminum relies on time well spent sanding the surface. After a few projects, you’ll learn how to sand and polish aluminum to the level you want. It’s all about knowing what sandpaper can do and how you can use it to achieve your desired final look.

There are many products you can use to sand your aluminum piece. It all depends on how badly in need of sanding the aluminum is. Brasso, Mother’s Mag and Aluminum Polish, and WD-40 are commonly used in sanding, but you can also use a Scotch-Brite pad and a wire brush if necessary.

Sanding accomplishes two tasks:

1. Removing any surface imperfections
2. Creating uniform scratches for a better result after polishing

Many people who don’t know how to make aluminum shine without polishing it will use WD-40, a Scotch-Brite pad, and some elbow grease to achieve a brushed look. The result is a bit more hazy and gray than you’d find with something that’s been polished to look like chrome. At the same time, it can be the perfect look for your application. Don’t underestimate the power of hand sanding.

If you want to know how to polish raw aluminum to mirror finish standards, you’ll want to begin by first tackling any imperfections in the piece. This requires moving from aggressive sandpaper grit sequentially to finer sandpaper grit. Whether you do this by hand or with power tools is your choice.

In order to achieve the mirror-like finish, you’ll want to start with 320 grit sandpaper and then work upwards from there. Most people move from 320 to 400 and then from there to 600, 800, 1500, and even 2000. The higher/finer grit you go with, the smoother your results will be.

As you sand, you’ll be leveling out the surface of the aluminum, as well as creating finer and finer uniform scratches along the surface. Once you get up to 1500 grit sandpaper, the scratches typically aren’t deep enough to see. Instead, you’ll polish those out in the next step for an impressive and shiny look.

Buff

Now that you’ve brought the physical surface of the aluminum to a smoother finish, it’s time to buff the outside to really bring out the brightness of that piece. Again, you’ll work from coarse cutting compounds to finer compounds that will gradually pull the luster from your aluminum workpiece.

Buffing begins with the following steps:

1. Use an orange airway and brown tripoli cutting compound at around 3500 RPMs. Remember, consistency is key to achieving a uniform and mirror-like look.
2. The next step is using a yellow buffing wheel with the green rouge cutting compound. You can use the same speed, or go a bit slower if you’d like. More experienced polishers who know how to polish aluminium with a buffer may even take these first two steps at 6000 RPMs, depending on the application.
3. With a flannel buffing wheel and competition purple buffing compound, you can achieve a respectable finish at about 2200-1800 RPMs.

As you work, you should notice that the aluminum surface is becoming brighter and achieving that mirror-like finish. While it might be tempting to continue polishing for a chrome-like look, the metal will only take so much before your rate of return diminishes.

Seal and Maintain

Doing all that hard work to figure out how to polish raw aluminum to mirror finish specs is worth nothing unless you seal and maintain your results. You’ll need to know how to protect aluminum after polishing for your results to stick.

You can spray sealant directly on your aluminum components, or you can use an aluminum wax to keep the pores clean and free of imperfections.

Once you’ve completed the main steps in bringing dull aluminum back to life, maintaining it is key to avoiding that process altogether. Using aluminum polishes by hand on a schedule can help you maintain your aluminum’s shine and keep your parts looking newer for longer.

Aluminum Polishing Tips

As you learn how to mirror polish aluminum, keep these tips in mind:

• For the most part, you should sand in one direction. This means moving up and down your aluminum piece in a back-and-forth motion. Such an approach helps to keep the surface of the aluminum piece uniform for better polishing results.
• If you’re unsure about how to polish aluminum with a new product, test it in a small area that isn’t noticeable. If your results are good, you can continue; if not, you don’t have as much area to improve later on.
• Use tape for areas where you don’t want to sand and/or polish. This can help protect the surface from any damage while you work.
• When you sand, don’t spend a lot of time on the edges. Excess sanding can actually round out corners and even wear down what once were sharp edges.
• If you find your sanding discs aren’t as effective anymore, replace them immediately. The particles stuck underneath the sanding disc can actually cause your sanding results to be less effective if there’s no grit to break them down.
• Don’t mix buffing wheels and cutting compounds. Dedicate wheels to particular compounds so that you can work efficiently through the buffing process. Otherwise, you’re introducing harsher grit to a process where finer grit is necessary.

As with any skill, time spent polishing aluminum will help build your skills and experience.

FAQs

What is the best way to polish aluminum?

The best way to polish aluminum starts with how you want to approach the task. Power tools certainly speed up the process, but polishing by hand can help you reach hard-to-get places with ease.

How do you shine dull aluminum?

You can shine dull aluminum with sanding paper and cutting compounds. Work from coarse to fine with both processes to achieve a desirable end result.

How do you polish aluminum to a mirror finish?

Knowing how to polish billet aluminum to a mirror finish begins with understanding the preparation processes of cleaning and sanding. Achieving chrome-like results takes cleaning the surface and sanding it to a smooth finish, typically with 1500 or 2000 grit sandpaper. Then, polishing up to fine-grit compounds should help achieve the mirror-like finish you’re looking for.

How can you polish aluminum with basic at-home products?

There are many household items you can use to create your own polish. Examples include baking soda and water, toothpaste, lemon juice, and olive oil. Just remember to use cream of tartar and water with any food-related aluminum pieces, as chemical compounds should not be ingested.

Final Thoughts

Learning how to polish aluminum takes time and effort, but it’s well-spent when you look at the results. You can easily shine up your aluminum pieces to live a longer life with the knowledge of how to polish aluminum from start to finish. Plus, it’s a skill you can take with you as you work through life and complete projects for pay as well as for fun.