How to Repaint Aluminium Doors and Windows 2020

Now with the current 2020 lockdown for COVID-19 you’ve decided you’re going to repaint your doors or windows, or maybe even both. Whether it’s because you’ve never quite warmed to the colour of your existing aluminium window frame or you’re feeling like an adventurous change of style, you’re determined to avoid hiring any outside specialists and do the job yourself.

Before embarking on this project you should read our Top Tips on Cleaning Aluminium Doors and Windows

Preparing Aluminium Frames for Home Painting

Painting aluminium surfaces is all about preparation. How so? We’ve written this guide to especially to help you repaint aluminium doors and window frames the correct way. Read on to make sure you’re prepared for the task at hand before you start.

Warning! Oil Based Primers and Spray Paint for Aluminium Surfaces

This guide may recommend the use of oil-based primers and metallic spray paints when painting bare aluminium surfaces.

• Please be careful to avoid toxic fumes by only priming and spray-painting in well-ventilated areas.
• Where possible be sure to wear the necessary goggles, gloves, or other protective clothes.

Cleaning Aluminium Frames for Windows and Doors

Before anything else begins, aluminium window frames and doors require thorough cleaning.

When re-painting doors, remove any extra hardware or accessories such as doorknobs, knockers and locks before cleaning. Protect the areas you can’t afford to stain, covering the floor around the door and nearby surfaces with tape or tarp.

Use a heavy-duty sponge, cloth and/or small brush with a combination of warm water and soap to remove visible dirt and contamination. Scratch away any loose rust and stains where possible before rinsing the surface clean with a cloth soaked in plain water. Finally, buff the aluminium surface until completely clean and dry.

Whether the door or frame is painted already or merely bare aluminium, this thorough cleaning process is absolutely necessary for ensuring paint will adhere to the material.

Top tip: You may also like to clean any panes of glass while you’re at it, as this can reduce the chance of dirt and water from the glazing leaking into your nice new paint job.

Spray Priming Aluminium – Essential Preparation

Most paints do not adhere easily to metals such as aluminium. Furthermore, aluminium surfaces are susceptible to wear-and-tear via contamination from fingerprints, oils and other sources of dirt. As a consequence, any aluminium surface that isn’t already painted needs to be primed – prepared, in other words, to guarantee a smooth and even surface in the final result.

For ease of use, many people recommend using a spray primer made especially for clean metal. However, primer can also be applied using a traditional roller or paint brush.

You should always use the primer in accordance with the manufacturer’s instructions. Whichever method you choose, the key is to provide an even and consistent coverage without allowing excessive gaps, drips or imperfections.

In cases where the door or frame at hand has a pre-existing coat of paint, primer is only needed when changing the colour or if the old paint coverage is deteriorating badly.

In any case, ensure the primer is allowed to dry before continuing with any next steps, noting that this process could take up to 8 hours, to be sure you can leave overnight.

Sanding Aluminium – Uneven Primed Surface on Frames

If the primed surface is particularly lumpy or uneven, a quick sanding can ensure the smoothness required for painting. This is more likely to be needed on doors, which are generally trickier to adequately prime in one pass.

Do Not Exceed 150 Grit Sandpaper

Using a sanding block and sandpaper – ideally not exceeding 150 grit standard – work the entire surface in one direction until it is dull and smooth. There should be very few bumps or imperfections remaining, if any.

Ensure that any dust or residue from the sanding process is carefully cleaned up with a cloth before continuing.

Painting Aluminium – Top Coat Surface Coating

First: ensure the paint you’ve selected is explicitly suitable for aluminium or metal. High quality acrylic paint should perform the job well on primed surfaces. Metal spray paint is another option, although it should carefully applied (and you should probably take the door off its hinges for best results).

Secondly: choose the right tools for the task. A panelled door, for example, might require a 4-inch roller for a consistent coverage of paint. On the other hand a door with a straight, flat surface should do fine with an average-sized roller, but the fiddlier task of painting a small window frame may call for a small paintbrush. We highly recommend using roller sleeves and ample masking materials to avoid any unfortunate painting mishaps!27

Apply your first coat of paint evenly with steady application of your brush, roller or spray can. Aim for slow up-and-down movements along the length of the frame or unit while working. Factor in edges and areas your roller can’t reach during these early phases, painting hard-to-reach places first in your initial coating.

Re-apply several coats until none of the aluminium metal or original colouring can be seen, while inspecting and compensating for any drips or runs with each layer.

Always let the last coat of paint dry – overnight, preferably – before applying any further coatings. And remember: thin coats of paint tend to add up to a better-looking result while taking less time to dry.

When all layers of paint are completely dry you can begin to tidy the final product. Remove any residual paint left on glass panes by using a sharp razor or blade, scraping flecks off horizontally and vertically in the direction of the surrounding aluminium frame. Be careful to leave a small amount of overlap between paint and glass – this should ensure the watertight seal of the unit remains intact.

When you’re happy with results you can safely remove any masking materials, re-attach any accessories you may have taken off and check everything works as intended. Hey presto – your fresh new look is achieved!

Thanks for reading

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