How to Paint Over Powder Coated Aluminium Windows?

I still remember the first time I held my paintbrush. I was 21 then and my project was to paint a metal window that was made up of aluminum.

Although the project wasn’t completed as it should have been – and my client was not very happy with it – the feeling that I did it myself still made me feel happy. Because that was the first project for which I was paid.

Anyway, I am not here to talk about all those stories.

In this article, I will be talking about what is powder coating. Why you should be painting your powder-coated aluminum windows and how to do that perfectly to get the right finish.

So, without any delays, let’s jump in…

What is Powder Coating?

Metal surfaces may be durable, but they’re not invincible. They need the right finish (along with regular maintenance) to keep them protected from rust, wear & tear, and other forms of deterioration.

The aluminum material of window frames is no different than any other metal surface. They need to be treated with a finish that keeps them protected for a long time.

Powder coating is one of the most popular types of finishes for metal surfaces, especially aluminum. It’s different from other metal finishes in a way that it is a dry powder rather than a liquid.

• The powder gets applied to the aluminum surface with an electrostatic spray gun.
• The electrostatic charge spreads the powder over the surface of the item.
• Then the heat is applied to melt the powder coating and make it harden onto the surface.

Since window frames take a lot of abuse from the moisture outside and the people inside, they’ll need a finish that can resist these actions each day. Powder coating can do that for the frames by offering different forms of protection, including moisture and scratch resistance.

Why You Need to Paint Powder-Coated Metal?

Powder-coated metal is often lauded for its durability and attractive finish, so it might seem counterintuitive to paint over it. However, there are several practical and aesthetic reasons why painting powder-coated window frames can be beneficial:

1- Customization

Painting the window and door metal frames allows for easy color changes that are otherwise limited by the original powder coat color range.

This is particularly helpful if you need to match new design schemes or personal preferences by applying a specific type of paint or finish such as metallic, matte, or textured finishes.

2- Restore Appearance

Powder-coated window framing can fade due to UV exposure, weather conditions, and general wear and tear. With time, the coating can also chip or scratch.

By carefully painting the surface you can restore or change the color, giving the metal a fresh, new look. This will also help conceal damages and imperfections while preventing further deterioration due to corrosion, rust, and environmental elements.

3- Maintenance and Longevity

In some cases, powder coat may not adhere well to certain areas or types of metal. Painting over these areas will ensure a consistent protective layer.

Additionally, it is simpler to retouch, clean, and maintain the painted surface compared to reapplying the powder. Especially if you use a high-quality, durable paint the ongoing maintenance will be more convenient and cost-effective.

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How to Paint Powder Coated Aluminum Window Frames?

Powder-coated aluminum window frames are getting increasingly popular in offices, car showrooms, and homes.

If you ever plan to alter the color and appearance of your windows, painting over the existing powder-coated metal is the easiest and most affordable option. However, to get the desirable results, here are the essential steps you will be required to follow…

Step 1. Clean the surface

Using an alkaline degreasing detergent solution and a soft brush thoroughly clean your aluminum window frames even if they are already painted. Follow the instructions on the detergent bottle to apply the cleaning solution correctly.

Keep in mind that any grease, dirt, or other debris left on the surface will make it harder for the primer and paint to adhere to the metal. So, when you’re done with cleaning and brushing, make sure you rinse the metal surface with warm water. Then let the surface dry on its own.

Step 2. Eliminate the corrosion

If there is any existing corrosion on the powder-coated aluminum, you need to strip away the deposits appropriately.

Any white rust on the powder coated metal surface can be eliminated with a nylon scrub pad but if you see red rust, you’ll need a power sander to remove it. After the corrosion is removed, wipe away the remaining dust with a tack cloth.

Remember that powder coatings are very hard and durable. They do not easily allow other coatings to adhere. To prepare the surface for recoating the powder and ensure better adhesion or primer and paint, I recommend lightly sanding the surface with 180-grit sandpaper. If you still see some bumps on the powdered coated surface, abrade the anodized aluminum correctly until you get rid of them.

Step 3. Mask the surface

Mask the areas of the window frames that you do not want to paint. These areas may include the glass panes, handles, locks, hinges, and any surrounding walls or trim.

Use masking paper, plastic sheeting, or decorators’ tape to cover these sections carefully, ensuring that the edges are sealed properly to prevent paint from seeping through.

For larger areas like the glass panes, you can also use newspaper or plastic sheeting in combination with the painter’s tape. Taking the time to mask these areas effectively will help you achieve a clean, professional finish and make the cleanup process much easier after painting.

Step 4. Prime the window frames

Now begin the priming process immediately or else the surface of your window frames might get dirty again.

A two-component epoxy primer is an excellent primer for powder-coated aluminum. However, you can choose a primer like Rust-Oleum® Professional Aluminum Primer Spray that is suitable for aluminum material.

Apply a little bit to the surface evenly with a small 2-3-inch brush or a mini roller. The primer should not smear or wipe away at all. If it does, then you need to abrade the surface again.

Step 5. Spray paint the aluminum frame

Finally, you need a top paint coat that is compatible with powder-coated aluminum.

IMO, a premium quality acrylic or latex paint that’s formulated for use on metal can be used for aluminum. Epoxy-based paints and enamels will also stick to powder coated aluminum window frames and can be a great choice. Although these are a bit costly.

Remember, if you are painting any outdoor aluminum window frame (or any aluminum patio furniture) pick the paint that’s labeled “exterior-grade”. If you are still doubtful ask someone at your local home improvement store for other recommendations as well.

Once you have access to the right type of paint for powder-coated aluminum, spray it on the primer-coated frames. Make sure you spray paint the surface in one direction and apply at least two thin coats to get the right finish.

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Challenges You May Face When Applying Paint Over Powder Coating

Although applying liquid paint over an old powder-coated window isn’t very tough, you may still face a few challenges.

The first and most important is related to adhesion.

Since the powder coat will create a very smooth and flat surface, any coating over the existing one may not bond properly to its underlying substrate. You should overcome this problem by sanding the surface prior to applying the primer/paint coat.

Secondly, if there is rust on an already powder-coated surface (due to oxidation), you may want to remove all the rust and powder coating before painting. This is important to avoid poor coating performance and keep the surface from chipping and cracking fast.

Powder coating can be removed from the surface using different ways which may include the usage of a chemical stripper, media blasting, or a burn-off oven. The method you will use to remove the powder coating will generally depend on the degree to which the powder coating is intact on the surface.

The Bottom Line

Painting over powder-coated aluminum windows is a fantastic way to make your old dull staircase aluminum window frames look new. Not only does it protect the surface from chipping, abrasion, and rust but also from other environmental damages.

However, when painting, you should choose the right paint products and properly prepare the surface for the coating. This will restore the appearance of the existing dull-out powder coat and will make your aluminum windows highly durable.