I still remember the first time I hold my paint brush.
I was 21 then and my project was to paint a metal window that was made up of aluminum.
Although the project completed was not very good – and my client was not very happy with it – the feeling that I did it myself still makes 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 for getting 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 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 offers different forms of protection, including moisture resistance and scratch resistance.
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.
Powder coating is in fact different from other metal finishes because 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.
Why You Should Paint Powder Coated Metal?
Powder coating comes in a variety of different colors.
The problem is that if you ever want to change the color, you either have to recoat the metal or apply a new color paint over the existing coat.
The easiest and most affordable option is to apply paint over the existing powder-coated metal.
Another reason to paint over powder-coated metal is if the coating chipped, cracked, or bubbled after it was applied originally.
You should not leave powder coating in this condition because its color will fade quickly.
The best solution is to paint over the chips, cracks, and bubbles of the coat.
That will add an entirely new color over the original color of the powder, so you won’t have to worry about it fading away.
How to Paint Powder Coated Aluminum Window Frames?
Powder-coated aluminum window frames are popular in offices, car showrooms, and also at homes.
There are six essential steps required for painting powder-coated aluminum window frames.
They are as follows:
Step 1. Clean the Surface
You need to clean your aluminum window frames even if its already painted.
There cannot be any grease, dirt, or other debris on the surface of them.
Otherwise, it will be more difficult for the primer and paint to stick to the metal.
You can use an alkaline degreasing detergent solution and a soft brush to clean the aluminum window frames.
Follow the directions on the bottle so that you know how to apply the cleaning solution properly.
When you’re done, make sure you rinse the metal surface with warm water.
Then let the surface dry on its own.
Step 2. Eliminate Any Existing Corrosion
If there is any existing corrosion on the powder-coated aluminum, you need to strip away the corrosion deposits appropriately.
Any white rust on the powder coating can be eliminated with a nylon scrub pad.
But if you see red rust on the metal surface, then you’ll need a power sander to remove it.
After the corrosion is removed, wipe away the remaining dust with a tack cloth.
Step 3. Sanding the Surface
Sanding the aluminum surface will ensure the primer and paint will stick to the powder coating.
The technical term for sanding metal is called “abrading,” but it is the same difference.
Anodised aluminum requires a lot of sanding to remove the bumps on the powdered coated surface.
Make sure you get rid of them.
Step 4. Mask the Surface
Before you begin priming the surface, you need to mask the areas of the window frames that you do not want to paint.
You can use masking paper, plastic sheeting, or decorators’ tape to do this.
Step 5. Prime the Surface
Now you can begin to prime the surface of the aluminum frames.
Try to do this immediately or else the surface might get dirty again.
You will need to choose a primer (like Rust-Oleum® Professional Aluminum Primer Spray) that is suitable for aluminium material.
As an alternate, you can choose a two-component epoxy primer. It’s also an excellent primer for powder-coated aluminum.
Apply a little bit to the surface evenly. The primer should not smear or wipe away at all. If it does, then you need to abrade the surface again.
Step 6. Spray Paint the Surface
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 will also stick to powder coating and can be a great choice. Although this can be a bit costly alternative.
Remember, if you are painting any outdoor aluminum window frame (or any aluminum patio furniture) pick the paint that is labeled “exterior-grade”.
If you want you can also ask someone at your local home improvement store for other recommendations on the paint that can be used to paint powder coating.
Once you have access to the right type of paint for powder-coated aluminum, you will need to spray paint it to the primer-coated metal surface of the frames.
You can do this either by using a good sprayer or with a paintbrush that can help get it done neatly.
Make sure you spray paint the surface in one direction and apply at least two coats to get the right finish.
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, the coating of paint 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 to 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 existing powder coating and will make your aluminum windows highly durable.
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Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.