How to Paint Aluminium Window Frames with Spray Cans

Jump to: Before you start · Products and tools · Preparation · Spraying · Drying and care

Before you start: is this a suitable DIY job?

Start with a small window that you can reach safely and protect properly. Painting several windows, upper-storey frames or an occupied room with difficult ventilation is a bigger undertaking than spraying a loose metal object outdoors. If you cannot control overspray and provide the ventilation required on the can, arrange professional help.

Open and close the window before starting. Painting will not fix leaks, failed seals, sticking rollers or damaged frames. Deal with those issues first. Check any window warranty and, for strata properties, the approval requirements for changing external colours.

This guide covers ordinary consumer aerosol cans. Do not substitute industrial spray-gun coatings, add hardeners or use a two-pack aerosol as though it were an everyday DIY product. Choose products whose labels support your surface and intended use.

Choose compatible spray cans and gather your tools

One consumer system to discuss with a Wattyl stockist is Killrust Etch Primer aerosol for prepared bare aluminium, followed by Killrust Epoxy Gloss Enamel aerosol. Both are offered in 300 g cans. Confirm the current labels, available colour and suitability for your window finish before buying.

Existing powder coating or old paint needs a separate compatibility check. Do not spray etch primer over the entire frame simply because aluminium is underneath. Ask the manufacturer which preparation and primer, if any, are appropriate over the finish already on your windows. Our spray-can paint and primer guide explains these choices.

• Compatible aerosol primer where required, and the matching topcoat in your chosen colour and sheen.
• The cleaner and abrasive grade recommended for the selected system.
• Masking tape suitable for the surfaces, masking film or paper, and floor protection.
• Clean lint-free cloths and a separate practice board or scrap surface.
• Eye protection, gloves and respiratory protection specified by the product label and safety data sheet.

Estimate the amount from the aerosol coverage information, allowing for the narrow frame profiles and overspray. Coverage figures for a tin of paint are not a reliable way to count spray cans. Buy enough of the same colour and finish for the job and keep the product references.

1. Clean and inspect the frame

Remove loose dirt first, then clean grease and contamination using the product manufacturer’s recommended method. Protect the surrounding materials from the cleaner. Let the frame dry and check corners and lower edges where moisture can remain.

Look closely for loose paint and exposed metal. If the existing finish is peeling widely, stop and assess whether stripping or professional preparation is needed. Do not bury unstable paint under a new topcoat. If an older coating could contain lead, have it assessed before sanding or scraping it.

2. Prepare the existing surface

Prepare sound paint or powder coating with the abrasive and method approved for your chosen products. Work carefully around glass and seals: the aim is a suitable surface for adhesion, not deep scratches or unnecessary removal of the factory coating. Treat exposed aluminium according to the primer instructions.

Remove sanding residue with the recommended cleaning method and let the frame dry again. Make a small test application on a discreet, correctly prepared area. Let it dry as directed and check for lifting, wrinkling or poor adhesion before painting the whole frame. Ask the paint manufacturer how to assess the test if you are unsure.

3. Mask everything that should stay unpainted

Use a clean, accurate tape line at the frame boundary and cover the glass fully. Protect adjoining walls, sills and floors, plus nearby furniture, paving and plants. Spray can drift farther than the visible wet pattern, so a narrow strip of tape alone is not enough.

• Keep rubber seals, brush seals and other flexible weather seals free of paint.
• Protect locks, rollers, hinges, sliding tracks and other moving or contact surfaces.
• Keep drainage openings clear; do not fill or paint them shut.
• Plan the sash position so you can reach the intended faces without closing wet paint against seals.

Avoid dismantling glazing or unfamiliar hardware. If a component prevents proper access, get advice rather than forcing it off. For why drainage matters, see A&L’s window-drainage explanation.

4. Prime only where the system requires it

Follow the primer label for preparation, application and the interval before topcoating. Keep the film even and avoid heavy build-up in corners. Bare aluminium and an existing painted surface may need different treatment; do not turn a bare-metal instruction into a blanket rule for every part of the window.

Check the primed areas for defects before topcoating. If you need to smooth an imperfection, follow the product’s sanding and cleaning directions. Allow the required drying time and remove residue before the next coat.

5. Practise, then apply the aerosol topcoat

Choose suitable conditions and remove ignition sources. Keep children, pets and other people away from the work area. Use the ventilation and protective equipment specified for the aerosol; a dust mask does not protect against solvent vapour.

Shake the can as directed and make a practice pass first. For the Wattyl topcoat example, its instructions specify approximately 25 cm from the surface. Use the distance on your own can if it differs. Keep your hand moving steadily rather than following the frame with a swinging wrist.

• Begin and finish each pass beyond the edge of the area being painted.
• Keep a consistent distance and use smooth passes with an even overlap.
• Build coverage without flooding corners or trying to cover everything in one heavy pass.
• Shake again during use as instructed, and check the nozzle if the pattern becomes uneven.
• Follow the stated coat count and recoat window. Do not assume every aerosol can be recoated after a few minutes.

If you see a run, resist spraying more paint onto it. Let the coating reach the stage specified for correction, then follow the manufacturer’s advice for smoothing and recoating. Rushing a repair can make the affected area larger.

6. Remove masking and allow the finish to harden

Remove masking at the stage recommended for the tape and coating, taking care at the painted edge. Do not drag a blade along glass or seals to free a stuck paint line. If the edge resists, pause and get advice before pulling away the finish.

Dry to touch, ready to recoat and fully cured are different stages. Follow the aerosol’s directions before operating the window, refitting removable items or cleaning. Avoid closing a freshly painted sash against its seals until the coating is ready for that contact.

Check that drainage openings and moving parts remain clear. Clean later with a method suitable for both the coating and the window manufacturer’s care instructions. Keep the colour, sheen and product details for future touch-ups.

Common spray-can mistakes to avoid

• Using a primer intended for bare metal over an unverified existing coating.
• Spraying onto dust, grease or loose paint.
• Skipping the practice pass and starting directly beside the glass.
• Applying a heavy coat to compensate for uneven coverage.
• Painting seals, tracks or drainage openings.
• Using a generic drying time instead of the directions on the actual aerosol.