Restore a Wrought Iron Gate With Hammerite Smooth in 6 Steps for 5-Year Protection

Strip a section of the gate down with a wire wheel on an angle grinder and you learn within minutes whether this is a two-hour job or a two-day one. Flaking surface rust comes away fast. Pitted, scaled rust that has eaten into the bar is a different problem, and it decides how much of the Hammerite Smooth claim you can actually bank on.

Hammerite is owned by AkzoNobel, sold across the UK and much of Europe, and the Smooth line is the one that goes straight onto rusted metal without a separate primer when the surface is sound. That single-coat-system convenience is the selling point. It is also where people get burned, because direct-to-rust does not mean direct-to-loose-rust.

Step one: get the surface back to sound metal

The coating bonds to whatever it lands on. Land it on flaking scale and the scale lets go in eighteen months, taking the paint with it. So the first job is mechanical. A wire cup brush on a 115mm angle grinder clears large flat areas quickly. For the scrollwork and the gaps between balusters, a wire hand brush and a set of needle files do the awkward bits a grinder cannot reach.

Work until you hit either bright metal or a tight, dark, stable oxide layer that does not shed when you drag a scraper across it. Pitting is the judgement call. Shallow pits hold paint fine. Deep pits that have hollowed out a third of the bar are structural, and no coating fixes a bar that is rusting from the inside. On a Victorian gate with original 19th-century ironwork, you will often find the verticals sound and the bottom rail half gone, because that is where rainwater sat for decades.

After the abrasive work, the metal needs to be clean and dry. Wipe it down with a cloth dampened in white spirit to lift grease, oily fingerprints, and the fine dust the grinder leaves. Let the white spirit flash off completely before painting. Any solvent trapped under the film causes pinholing later.

Step two: dewax, then keep your hands off it

Skin oil is invisible and it ruins adhesion. Once the gate is cleaned, handle it with nitrile gloves or by the edges you have already coated. A single thumbprint of grease shows up months later as a coin-sized blister.

Choosing between Smooth, Hammered, and the curable times

Hammerite sells three finishes that matter for a gate: Smooth, Hammered, and the Direct to Rust metal paint in the same family. Smooth gives a flat gloss that reads as modern and shows every imperfection in your prep. Hammered gives a dimpled, textured finish that hides pitting and uneven surfaces, which is why restorers reach for it on old, scarred ironwork where a perfect surface was never going to happen.

For a five-year exterior result, both work, but the application windows differ. The tin states touch-dry in roughly one to two hours and recoat after about four hours at 20C. Drop the temperature to 10C and those times stretch considerably. Below 8C or above 80 percent humidity, the solvent-based film does not cure properly and you get a soft, fingernail-markable surface that never fully hardens. That is the single most common reason a job done in a damp October fails by spring.

Two thin coats outlast one thick coat every time. A heavy coat skins over on top while the layer underneath stays soft, and the trapped solvent eventually crazes the surface. Thinner films flash off evenly. On a standard 1.2m garden gate, expect to use somewhere between 250ml and 500ml depending on how much scrollwork catches the brush.

If you are spraying rather than brushing, Hammerite sells an aerosol version, but the brush-on tin gives a thicker film per coat and better coverage into the pitting. Brushing also lets you work the paint into the gaps between balusters where spray drifts straight through.

Step three through five: the actual coats

Load a natural-bristle brush, not a synthetic one, because the solvent in Hammerite softens cheap synthetic filaments. Start with the fiddly bits: the scrolls, the joints, the undersides of the horizontal rails. These are the spots that get missed and the spots where water collects, so they earn the first pass while your brush is freshly loaded and your patience is intact.

Then lay off the flat verticals in long, single strokes top to bottom. Do not overwork it. The paint self-levels to a degree and going back over a tacky area drags it. Coat one is thin, almost stingy. You are not aiming for full colour, you are aiming for a continuous film keyed into the metal.

Leave the recoat interval the tin specifies, which at 20C means roughly four hours but realistically often overnight if the evening cools. Coat two builds the colour and the film thickness that does the actual weather protection. If the pitting is deep, a third coat on the worst areas only is worth the extra hour. Hammerite recoats onto itself cleanly within the curing window. Miss that window by several days and the surface needs a light scuff with 240-grit before the next coat will key properly, because fully cured Hammerite is glossy and the new layer slides on a polished surface.

The gate hinges and the latch deserve attention here too. Paint seizing into a hinge pin is a real annoyance. Mask the moving surfaces of the pintle and the latch tongue, or wipe paint off them before it sets, then oil them once everything has cured.

Watch the weather for the full cure, not just the recoat. The film reaches handleable hardness in hours but does not reach full chemical cure for several days. Rain in the first 24 hours after the final coat can bloom the surface, leaving a dull patch that has to be flatted and recoated.

Where the five years actually comes from

The number on the tin is a manufacturer durability claim under reasonable conditions, and reasonable conditions do a lot of quiet work in that sentence. A south-facing gate that bakes and a north-facing one that stays damp age at different rates. Coastal salt air is harder on any coating than inland air. The five years assumes sound prep, the full coat system, and curing within the stated temperature band.

What extends it is the boring maintenance nobody photographs. Once a year, walk the gate and look for the first chips, usually at the latch, the bottom of the gate where boots and lawnmowers catch it, and any horizontal surface that holds water. A chip touched up in its first season stays a chip. Left a year, it becomes a rust bloom that creeps under the surrounding film, and now you are back to the grinder.

A worked timing example for a single weekend

Take a typical 1.1m by 1.0m wrought iron side gate with surface rust and two deep pits on the bottom rail. Saturday morning, two hours with the grinder, wire brush, and needle files gets it to sound metal. Thirty minutes to wipe down with white spirit and let it flash off. First thin coat goes on by late morning, around 250ml of Hammerite Smooth, taking maybe 45 minutes including the scrollwork.

By mid-afternoon at 18C, the surface is touch-dry and ready for the recoat window. Second coat goes on before evening, another 200ml or so. Overnight cure. Sunday, a spot third coat on the two pitted areas takes twenty minutes and a few millilitres. Rehang or unmask the hinges, oil the pin, and leave it untouched through the day for the film to keep hardening. Total active time is under four hours across two days, with the rest being dry-time you spend elsewhere.

The variable that breaks this schedule is temperature. Run the same job in March at 7C and the four-hour recoat becomes a next-day recoat, the two-day plan becomes a four-day plan, and a single rain shower mid-cure resets you. The paint does not care about your weekend.

The open question on any old gate is what the grinder reveals under the rust. A tin promising five years means little if a third of the bottom rail has already corroded to a shell, and that is the one thing you cannot know until you start removing material and feel how much sound iron is left underneath.