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How to Polish Aluminum - A Beginner’s Guide

Jul 13th 2020

How to Polish Aluminum - A Beginner’s Guide

Have you ever seen an aluminum surface that you can see your own reflection in? Have your aluminum wheels started to look dull and tarnished over time? Well, it’s 100% possible for you to polish aluminum to a mirror finish that looks brand new.

Proper upkeep and care can extend the lifespan and enhance the appearance of all metals. It is a good practice to have whether you’re working with a metal like cast iron which should be seasoned regularly, or even stainless steel to get out scratches and gouges from regular use. All of the up-keep will help prevent metal from rusting and corrosion while also allowing it to maintain a visual appeal.

Aluminum is a beautiful metal, but it’s surface can get faded or discolored with time. Naturally, aluminum is very prone to corrosion, which leaves it looking dull as an aluminum oxide skin builds up to protect the metal. Even though aluminum is rust-proof metal, it is still prone to pre-rust if a carbon based abrasive has ever been used on it. Properly polishing it allows you to keep it looking pristine and prevent it from looking tarnished or showing any signs of pre-rust.

There is definitely a wide range of aluminum surfaces that could be covered here. Different tools may be required based on the surface being polished - hand polishing aluminum cookware versus polishing aluminum wheels versus polishing giant aluminum tanks and semis. Still, the general steps taken are the same. Below is an overall guide for how to polish aluminum the right way.

Polishing aluminum to a mirror shine is basically a 3 step process:

  1. Cleaning/prepping the aluminum
  2. Sanding the aluminum
  3. Cutting/Polishing the aluminum

STEP 1 - CLEANING ALUMINUM

How to Clean Your Aluminum

Clean the entire aluminum surface using a wet rag or sponge and cleaning solution, making sure to get rid of any debris, grime, dirt, dust, etc. In most cases, you can clean your aluminum with regular dish soap or a mixture of water and vinegar. This works perfectly fine for smaller projects. Commercial cleaners like Metal Pre-Clean can be used for larger projects or industrial jobs.

A strong degreaser or paint thinner may be needed if oil or grease is built up on the surface.

If you have a hard time getting stubborn grime off, you can use a screwdriver or a stainless steel wire brush to remove it. Do not use carbon steel as that can cause after-rust.

Thoroughly rinse the area with clean water and dry completely using a soft cloth.

STEP 2 - SANDING ALUMINUM TO POLISH

How to Sand Aluminum

This is the step that some people love and most people hate, but the most important step to get the best finish possible! To get the best results, you should be spending the majority of the polishing process sanding the surface.

Like most sanding jobs, you’ll want to start with a coarser grit sandpaper and work your way down to a finer one. With the exception of something like a truck tank, this will require nothing coarser than 320 grit abrasive. However, if you have deep gouges you need to get out, you may need to go to a lower grade. We do not recommend going below 180 grit for your abrasive.

You will work from the lowest grade which would be 180-320 depending on the severity of your project and work upwards until you have the deepest scratches or gouges sanded out. Many professionals recommend going from 320 grit, to 400 grit, and finish with 600. The real detail oriented polishers will sometimes go to 800 or even 1500 grit before moving onto the next step.

Smaller aluminum pieces can definitely be done by hand with sandpaper and a little elbow grease, but when you get into bigger projects, you’ll want to use an abrasive with a power tool. You don’t want to rush this process, but you also don’t want to spend hours and all of your energy sanding by hand. The best option for speeding up the sanding process would be to use an orbital sander with PSA discs or an angle grinder with an aluminum grinding flap disc.

Why is Sanding Such an Important Step?

Do you want your aluminum to shine? Do you want a mirror finish you can see yourself smiling back at? Well, the sanding is what gets you there.

In order to get such a reflective surface or to create a shine, you need to remove and flatten out all the irregular surfaces on the aluminum, or any metal really. You can run your hand over the aluminum and think it feels 100% smooth, but at a microscopic level it isn’t.

Light hitting a rough surface, even at a microscopic level, will become diffused and make the metal look dull. A smoother surface will reflect the light more, giving it more of a shine and a mirror-like finish.

While you can never make the aluminum surface completely flat and smooth, you can get it to a noticeable level. The only way to do that is to sand it down layer by layer with a finer and finer abrasive.

STEP 3 - BUFFING/POLISHING THE ALUMINUM

You’ve now, finally, made it to the part of this job where you get to actually buff out the aluminum and start to see the real shine! It’s time to polish and buff your aluminum.

Small Polishing Jobs

If you’ve taken my advice and properly prepped your aluminum with a focus on the right sanding technique, then this should be a fairly easy process. All you are going to need here is a clean cloth or two and aluminum polish.

Start by applying a small amount of the aluminum polish to the area. Continue to wipe it into the surface by using small, circular motions. Using either a fresh cloth or a clean and unused side of the original cloth, wipe away all of the polish. Once all of the polishing residue is gone, take another clean cloth and buff the entire surface using the same circular motions as before.

If you are polishing anything that will have food on it, like an aluminum pan, DO NOT use aluminum polish. This can be dangerous if ingested. Instead, you can use an equal amount of water and cream of tartar (potassium bitartrate) as a homemade DIY polishing compound.

Larger Polishing Jobs

When you get to a job that could take a long time by hand or require a little too much elbow grease, you can always lean on a trusty power tool to get you through the work. There are a lot of options available for the actual cutting and polishing part of this process. For the buffing tool, most people find that one of the easiest and most efficient tools to use is an angle grinder with airway buffing wheels or conventional muslin buffing wheels.

Start by adding a bit of your coarsest abrasive compound to your stiffest buffing wheel. We recommend using buffing compound bars for the polishing process. Working in sections, buff the entire surface, adding more polishing compound as needed. Once you are done with this step, completely wipe off all of the residue and change your buffing wheel.

Just like sanding, you’ll want to start with the coarsest abrasive and work your way down. If using compound bars, start with brown tripoli aluminum abrasive compound then move onto white rouge. This should usually get you the mirror finish you want, but for those of you with perfectionist tendencies, you can finish up with a green rouge compound bar to get the best aluminum shine possible.

Make sure to always use a different buffing wheel with each abrasive compound. Mixing the compound on your wheel defeats the purpose of moving down to a finer abrasive with each step. You can however reuse a buffing wheel in the future as long as you use the same compound on it each time.

When you finish your last buffing step, give your aluminum one last wipe-down with a clean cloth. At this point you should be able to see yourself smiling back at your mirror finish.

EXPERT TIP - Empire Abrasives offers a line of polishing buffing discs that can get the best shine in the final step of the buffing process before the wipe-down. The flap disc option continues to get great reviews. If you have a huge surface, like an aluminum tank, we also carry buffing drums that can get the job done incredibly fast by attaching it to a burnishing tool or contour grinder.

Chat With Our Team of experts

We offer a wide variety of aluminum polishing and buffing options and if you’re still unsure or undecided please give us a call at 1-800-816-3824 or open that chat on the bottom right hand of your screen. We’re always happy to help.