Maintenance
How to Maintain a Wrought-Iron Window Bar
Bare steel rusts if left unprotected — the finish applied at manufacturing largely determines how long an outdoor window bar lasts, and how little upkeep it will need afterwards.
Three finishes, three levels of protection
Galvanising (dipping in a zinc bath at around 450°C) creates a zinc coating that acts as a sacrificial anode: it corrodes in place of the steel and protects the metal as long as the coating isn’t fully consumed, needing very little maintenance while intact.
Powder coating (polyester powder paint, oven-cured) offers good UV resistance and better colour stability than epoxy powders, but mostly protects at the surface: once the film is scratched through to bare metal, rust can start underneath.
The duplex system (galvanising followed by powder coating) combines both: combined service life can reach up to 2.5 times that of either treatment alone, according to anti-corrosion industry technical sheets. It’s the most durable finish for an outdoor installation exposed to weather.
How often to maintain a window bar
A visual check once or twice a year (after winter, for instance) helps catch early rust before it spreads. For a localised rust spot, light sanding followed by a touch-up of paint is usually enough if caught early.
Mistakes that speed up rust
Mixing different metals without isolation creates a galvanic pair: near the coast, salt-laden air acts as an electrolyte between two different metals (for example, a mismatched screw in a fixing), accelerating corrosion of the less noble metal.
Painting freshly galvanised metal too soon is another common mistake: fresh zinc typically develops “white rust” (zinc oxide/hydroxide) within a year of galvanising, and this layer — along with any protective oils — must be removed before painting, or the paint won’t adhere properly.
In coastal environments, industry sources often recommend stainless steel or aluminium over painted or galvanised steel alone, which is more vulnerable to sea spray over time.
Frequently asked questions
Which finish lasts longest for an outdoor window bar?
Duplex (galvanising + powder coating) offers the best service life, up to 2.5 times that of a single treatment, according to industry technical sheets.
My bar has a rust spot — do I need to replace it?
Not necessarily: a localised spot caught early (light sanding, touch-up paint) is often repairable without replacement. Extensive rust or rust near a weld is worth a professional’s opinion.
Does living near the sea change which finish to choose?
Yes: sea air speeds up corrosion, especially where different metals are in contact. Stainless steel or aluminium are often recommended near the coast over steel alone.