Aluminum is the most common metal freely available on the earth’s crust and is certainly one of the most versatile ones.
However, painting it can often seem like a daunting proposition. After all, aluminum isn’t just any other regular painting surface. It’s a metal, which means not only is it prone to damage, but it also lacks the rough texture a surface requires to cling on to paint efficiently.
Hence, it isn’t surprising to see people at a loss regarding where and how they should start when it comes to painting aluminum. But it is for these people precisely that we have come up with a comprehensive step-by-step guide on how to do just that.
So, without wasting any more time, let’s jump right into it!
Step By Step Process Of Painting Aluminum
Clean And Degrease Aluminum Surface
Although most how-to guides available on the internet completely neglect to mention this step, we consider it very crucial for prepping the project. All you have to do is wash and rinse the aluminum surface you plan to paint to make sure it is entirely free of grease and debris.
For the purpose of cleaning, you’re going to need to mix a bowl of warm water with any standard degreasing agent or dish soap. After that, you simply need to dip a rag in the soapy solution and wipe down the aluminum surface.
Rinse the surface with plain water to remove any soapy residue afterward, and then dry it off with a clean cloth. If you’re working with an aluminum surface that already has paint on it, please make sure to skip this step and start directly from the next one.
Remove Old Paint (Optional)
If your aluminum surface already has some leftover paint on it, you will need to invest in some paint scraper and after-wash. These products are usually freely available in every home improvement store, so they should not be too difficult to find.
It’s best to follow the instructions on the label of the paint scraper while using it because different brands tend to have different methodologies. However, usually, all you need to do is pour the solution on the metal and then scrape it off with a paint scraper after a few minutes.
Follow this with the “after wash” to remove any of the leftover paint residues. After that, rinse the aluminum surface of your project and dry it with a clean cloth as instructed earlier.
Aluminum Corrosion Removal (Optional)
If the surface of your aluminum piece has a hard white-ish layer of oxidation on it, then it is recommended to remove that before moving forward with your painting job. The oxidation will otherwise interfere with your paint and not let the enamel effectively adhere to the surface.
To remove this layer, you will need some warm water, a degreaser (same as the one you used on the first step), and a wire brush or steel wool. The methodology of this step overlaps with step one, so if your metal surface has any signs of oxidation, this step is essentially clubbing two steps for you.
Like we mentioned earlier, create a soapy solution and spread it all over the aluminum surface to clean it. Follow that by using the wire brush or steel wool to scrub at any of the oxidized parts of the metal until they are smooth and shiny again.
After having scrubbed off the entire layer of oxidation, rinse the surface with some plain water to get rid of any soapy residue and dry it with a clean cloth as usual.
Alternatively, you can also invest in a range of different diluted acids such as diluted hydrochloric, phosphoric, or even sulphuric acid to remove the corrosion on your aluminum. Another option would be to create your own homemade cleaner by mixing equal parts of white vinegar and water.
Apply this diluted acid or cleaner to your aluminum surface and rub it with a wire brush or steel wool as instructed above. In this case, you should first clean and rinse your metal surface as described in step 1 before going in with the homemade cleaner or diluted acid.
If that still doesn’t do the trick, you might want to buy a commercial aluminum cleanser and follow its instructions to do the cleaning.
Sand The Surface Of Aluminum
Sanding the aluminum surface is often a step that beginners and DIY enthusiasts overlook because of how grueling and time-taking it can be. But we would like to emphasize this as one of the most crucial prepping steps in our guide.
For this to work, you will need to invest in coarse and fine sandpaper that has about 80 to 100-grit and another one that is at least 400-grit. Use these sandpapers to buff the surface of your project in smooth circular motions.
Do the first round with the 80-100 grit sandpaper and follow that with a second round of scuffing with 400-grit sandpaper. This step will provide the aluminum surface with some texture to let the paint have something to stick to.
We highly recommend that you wear a dust mask, work gloves, and safety goggles for this step. The metal sanding dust that gets released into the atmosphere while sanding is not safe to breathe in.
We also recommend investing in a high-quality face mask, preferably one that is specifically rated to shield you against sanding dust.
Remove Excess Dust And Dirt
Once you’re done evenly sanding the metal surface, wipe the extra dust (that the above step will have created) off with a tack or micro-fiber cloth. This is important to ensure that the spray paint you apply goes on evenly instead of being applied on sandpaper residue and thereby causing imperfections.
You can also re-rinse the surface of the project with warm water and degreaser/ dish soap as we did in step one if you have more time on your hands. Rinse thoroughly with water and then let the project air dry before moving on to the next step in the latter case.
Separate Any Areas You Don’t Want To Paint
If you’re working on an aluminum project that you don’t want to paint entirely, you’re going to need to invest in some masking tape. Maskings tapes are incredibly common stationary staples that are available in almost every other arts and crafts or hardware store.
Use this tape to section out or cover areas that you don’t want the paint spilling onto, just like you would do on a canvas. If you’re planning to mask off a substantially large area, make sure you cover it with a paper or plastic sheet and then secure the edges with the tape instead.
This tape is going to be removed as soon as your last coat of paint is dried, so don’t worry about making it look perfect.
Purchase A Self-Etching Primer
Now we come to one of the most crucial steps of any painting process, also known as priming. For the purpose of priming your aluminum project surface, you are going to need to invest in a high-quality, self-etching primer that usually comes packaged in aerosol cans.
Do not just use any regular primer for this job, even if it mentions that it is suitable for metals. These primers seldom give the finish that we are looking for.
We highly recommend you carefully read the label of the primer you are about to use. Most companies will mention the ideal temperature range that you will need to work in as well as any other precautions that you might need to follow. We also suggest you carry out the priming job in a well-ventilated area like a painting booth outside your home.
Apply Multiple Coats of Your Chosen Primer
As we mentioned above, the primers we want you to use come in aerosol cans and hence tend to release toxic fumes that cause lightheadedness and headaches. So carrying out the priming process outside prevents the spray paint from getting on indoor surfaces and also keeps the poisonous chemical fumes out of your house.
A respirator mask is absolutely necessary while carrying out this step. It’s also best to avoid priming when it is humid or raining outside as this can affect the curing process.
Now coming to the priming process itself, you will first need to shake the primer can for about 30 to 60 seconds. Hold the nozzle about 8 inches or 20 cm away from your project surface and spray lightly in even and overlapping strokes. You may have to get creative about holding the project up while spraying it with primer; and try to keep your hands out of the spray area.
It’s also imperative to make sure you continue to spray paint in the same direction throughout, whether that is side to side or top to bottom. One of the tricks for getting an even finish on your aluminum surface is overlapping each of your painting strokes very slightly. If your project has multiple sides, then you must let the first side dry to touch before moving on to the other side.
Overall, we recommend you apply about 3-4 coats similarly as we have described above. You will need to let the primer rest for about 5-15 minutes between each coat to ensure a smooth and radiant finish.
Buff Away Any Imperfections As Required
The brand of the primer you purchase will always mention the curing time of the product in the label of the aerosol you bought it in. Hence, once the primer is cured, you must take a good close look at the aluminum surface.
If it looks a little too uneven, buff, or drippy, then you can go in with 400-grit sandpaper and buff it up before moving onto the next step. However, if you already like the finish that the primer gave the project surface, then skip this step entirely.
Apply Multiple Coats Of Your Chosen Paint
Finally, we come to the step that this entire guide is written about. When choosing the kind of paint you want to buy, try to get your hands on either acrylic or latex paint. For the most professional results, we suggest you get a paint that either has a matte or a satin/ metallic finish.
While glossy finish paints can also be used for this project, they tend to highlight the imperfections of aluminum, which is why we recommend avoiding it.
Also, since you’ve already primed the aluminum surface you get the freedom to choose any type of paint. The paint does not need to have a label that mentions it is “for metals” for it to look good on a freshly primed surface. However, if the piece you are painting is meant to be outdoors, you might want to buy paint that is explicitly labeled for exterior use.
As you may already know, there are broadly only two ways to paint an object, via paintbrush and via spray can. While spray paint is quicker and easier to apply, brush painting your project is also a viable option when it comes to aluminum-based projects.
Just like we recommended with the primer, you will need to apply this paint in even and slightly overlapping strokes for optimal coverage. If you’re painting with a brush, it’s most ideal to use a larger-sized flat brush with synthetic fibers. On the other hand, if you’re using spray paint, shake the can for 60 seconds and hold it at least 8 inches away from the surface of the project.
For painting a project with multiple sides, always wait for the paint to dry to touch before flipping it on the other side. This usually takes about 15 minutes but depends on the brand of paint you are using.
In general, it’s best to apply at least 3 coats of color for a flawless and long-lasting finish. However, we suggest checking the paint label to know how long you need to wait between coats.
Allow The Paint To Cure
The paint does not need to be cured between coats; however, after you’ve applied the last coating, we recommend setting your project aside for at least 24-72 hours. The exact cure time for the paint will again, depend on the brand of paint you are working with. If the brand mentions both curing and drying time, always consider the curing time as your final reference.
Just to be clear, drying time is the time a paint requires to feel dry when you touch it. Alternatively, curing time is the time it takes for the paint to harden and preserve fully. After the curing time lapses, it is safe to wash the painted surface or keep objects on it. Therefore, once the paint has cured, it hardens up and is more resistant to scratches and jolts of day-to-day life.
Apply A Few Coats Of Clear Enamel (Optional)
This last step is actually an extra step we have included if you want the paint to be even more solid and long-lasting than usual. This step is specifically ideal for objects that will be used on a daily basis or are meant for the outdoors and hence go through more wear-and-tear than usual.
For this, all you will need is a clear enamel paint that you can easily find in both art-and-craft as well as hardware stores. Similar to the painting process, apply 3-4 coats of this enamel in light overlapping strokes while giving some time for each coat to dry in between.
Let this enamel cure for another 24-72 hours, according to its label, and you will have a flawlessly painted aluminum surface.
With that, we come to the end of our rather detailed step-by-step guide to painting aluminum. I hope we were able to answer all of the questions and queries you may have had regarding the process. We highly recommend that you follow each of our steps in the very same order to achieve the best results.
And in case you want to add that extra edge to your project, then consider using the optional steps as well. We’re sure they will make your aluminum paint job look much better than any normal painted surface.
So what are you waiting for? Time to start painting!