Painting Aluminum

Aluminum has great properties that make it an ideal construction material. It is easy to work with, durable, lightweight, and has a high resistance for corrosion. In most cases, its sleek silvery-white finish is enough, but if you want to give it a custom look, you could consider giving it a coat of paint.

Because aluminum is a non-ferrous metal, painting is a lot trickier compared to other metals. You need to follow the set steps cautiously for the best results.

Materials you will need:

  • Drop cloth

  • Degreasing detergent

  • Wire brush

  • Sandpaper or sanding block

  • Self-etching spray primer

  • Acrylic spray paint

  • Enamel sealant

1.       Clean the aluminum

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Before you can transform the aluminum, you need to clean it first. Find an open, well-ventilated area and lay the drop cloth to prevent the surrounding from paint transfers.

Fill a large bucket with warm water and mix it with a degreasing cleaner. Dip a rag into the solution to remove dust and dirt from the surface of the metal.

If the surface is covered in rust or has some old flaking paint, you need to scrub these off using the wire brush because they can prevent the new coat of paint from adhering.

2.       Sand the metal surface

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After cleaning the surface, let it dry completely. Next, pick up the sandpaper to sand the surface. It's vital to have the right protective gear at this point.

Sand all the sides, crevices, and corners of the object. Start with a coarse sand grit paper like an 80 to 100 grit paper to sand the surface then repeat the process with a finer 400 grit or higher sandpaper.

Rewash the piece with warm water and degreasing cleaner to remove any particles and dust and allow the metal to dry completely.

3.       Apply self-etching Primer then sand again

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A self-etching primer is crucial in painting aluminum. Its formulation contains chemicals that etch into the surface of aluminum for the best bond. To apply the primer, spray it in thin coats according to the manufacturer's recommendations. 

Allow the primer to dry completely, followed by light sanding with a fine-grit (400 grit or higher) sandpaper, and wipe away the dust using a rag.

4.       Apply the paint

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Latex or acrylic paints are the best for painting aluminum. Choose the ones designed for use on metal. If you’re handling an outdoor project like patio furniture, ensure the paint is exterior grade.

Tempting as it might be, don't go for high-gloss paints because they will highlight imperfections on the surface.

Based on your paint choice, you can spray it or use a paintbrush. Always make sure you follow the manufacturer's recommendations for the best results, especially on the number of coats and if sanding between coats is possible.

5.       Apply the sealer

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After the paint has dried completely, you can apply at least two coats of enamel sealer. This protects the paint from chipping, fading or scratching over the years. Follow the recommendation on cure times before you can use your aluminum object.

In these five simple steps, you can paint aluminum. If you’re chasing perfection, take time on the surface preparation and try to get the smoothest finish possible to ensure the best results.