Steel window frames, security bars, sills and metal fittings face rain, wind and condensation all year round. In winter moisture collects on the cold metal and runs into corners and seams, which is exactly where the first orange patches and paint blisters appear.
Left alone, rust eats into the surface, the paint flakes and the fittings start to stick. Light bloom can be removed with a vinegar solution, while stubborn rust is best softened with a penetrating lubricant before you restore the paint.
What you will need
- bucket, white vinegar and water
- soft brush and a wire brush for deeper rust
- fine abrasive paper
- clean cloths, masking tape, sheeting to protect the sill
- WD-40 Multi-Use
- metal primer and paint
Important: Protect glass, seals and sills with sheeting and masking tape. Keep vinegar off marble and stone sills. When working at height or outside, use a stable ladder and a safety line.
Step 1
Remove light bloom with vinegar
Mix vinegar and water in equal parts in a bucket. The acetic acid reacts with rust and helps release it from the metal.
Apply the solution to the frame with a soft brush, scrub the affected areas and rinse with clean water. Dry the frame thoroughly: water left in the corners will start corrosion again.
Step 2
Treat stubborn rust with WD-40
Rust that has bitten into the surface will not shift with vinegar. Apply WD-40 Multi-Use and leave it for 10-15 minutes to work under the rust.
Then clean the area back to sound metal with a wire brush and fine abrasive paper. Wipe away dust and lubricant residue with a cloth.
Step 3
Degrease and repaint the frame
There must be no lubricant left before painting, so wipe the cleaned areas with a degreaser. Apply an anti-corrosion primer and, once dry, two thin coats of metal paint.
Paint on a dry day above freezing so the coating bonds well.
Step 4
Look after the fittings
Treat hinges, handles, catches and window locks through the thin straw of WD-40 Smart Straw, then open and close the sash several times to spread it. Wipe off the excess.
Wipe the rubber seals with WD-40 Specialist Silicone so they stay supple in frost and do not freeze to the frame.
Step 5
Protect the metal from fresh corrosion
Wipe unpainted metal parts, bars and sill fixings with a cloth and a little WD-40 Multi-Use. The thin film displaces moisture and slows new rust.
Check frame corners and seams every autumn, as that is where trouble starts first.
Tip: Condensation on metal frames in winter often points to poor ventilation. Air the room more often and do not cover the radiator under the window with heavy curtains, and the frames will stay dry.
What next
Inspect and treat the frames twice a year: in autumn before the frosts and in spring after the snow melts. Touch up chips straight away, before rust spreads under the paint.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».