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Metal paint for gates and railings

Updated: 23 October 2026

You are repainting a rusty iron gate or a run of garden railings, and the face from the path looks like the whole job. It is not. Metal paint for gates fails first on the edges, the welds and the bottom bar, where water sits. This page is whether a 250 ml tin is even plausible, and what to coat besides the pretty side. The [metal paint comparison](/hub/paints-and-varnishes/metal-paint) holds the saved prices. Peter F. updated this page on 23 October 2026 from Hammerite’s UK coverage rate and the amazon.co.uk listings. We have not measured your gate. A qualifying purchase through our links can earn a commission at no extra cost to you.

You are repainting a rusty iron gate or a run of garden railings, and the face from the path looks like the whole job. It is not.

Our top picks

Hammerite Hammerite 5158235 smooth black

Best overall

Hammerite Hammerite 5158235 smooth black
9.4/10about £20.43
View offer
Hammerite Hammerite smooth black 750 ml

Alternative

Hammerite Hammerite smooth black 750 ml
9.4/10about £22.00
View offer
Hammerite Hammerite smooth black 250 ml

Best value

Hammerite Hammerite smooth black 250 ml
9.2/10about £9.97
View offer
On this page
  1. 1.What part of the gate actually rusts
  2. 2.How far the tin goes
  3. 3.Order of work on bars
  4. 4.When to stop

What part of the gate actually rusts

The bottom rail and the lower ends of the bars collect rain and splash. Edges and corners lose film first, which is why a coat that looks even from the house can rust along the arris by the next winter. Welds hold moisture in the grind marks. If you only roll the flat face, you have painted the part that was already coping. Prep is the same order as any rusty steel. How to apply metal paint is that order in full. Wire-brush what is loose, wash grease off, and patch-test sound old paint for about an hour. Leaf-sized scale still has to come off. One review used special metals primer on gate hinges. That is an extra step on fittings, not an ASIN in this table. Smooth black is the default here. Check gold in daylight if the gate is not black.

How far the tin goes

Hammerite’s smooth page uses about 5 m² per litre. Two coats on bare rust are a rule of thumb of about 0.6 m² from 250 ml and about 1.9 m² from 750 ml. One 750 ml tin can cover a short run of railings and still struggle with both sides of a bare gate. Listing fields run from 2.5–3 m² per litre up to 12 m² per litre on part 5158235. Buying from the 12 m² figure runs you out on the back of the gate. The clashes are on the metal paint buying guide. Smooth black 250 ml is £9.97, best value when the job is a short rail. The large blacks are £20.43 (4.7 from 7,075) and £22.00 (4.7 from 1,454). The £20.43 listing does not agree whether it is 750 ml or 1 l.
Hammerite Hammerite 5158235 smooth black

Testsieger

Hammerite Hammerite 5158235 smooth black
9.4/10about £20.43
View offer

Order of work on bars

Pick a dry day inside about 8°C to 25°C. Hammerite’s gate article asks for the details first, then the front, the back and the sides. Start with the bottom edge and the welds. One review aims to paint below 20°C because the enamel dries on the brush. Bare rust wants two coats, about 4 hours apart. Do not flood the bars. A run is a thin edge tomorrow, and going back over wet paint lifts the film. The top pick here is the large black tin with 7,075 reviews, if you check the fill. The £22 tin is the one whose reviews open on railings, a patio set and a garage door, with dry-time fields that disagree. A 30 ml bottle is the wrong object for either.

When to stop

If the bars are shiny zinc rather than rusty steel, Direct to Rust is not the first coat. Hammerite wants Special Metals Primer on galvanised steel, zinc and aluminium. None of these ASINs is that primer. A salt-coast gate and a bottom bar that stands in water ask more of a one-pack film than a sheltered garden gate. The up-to-8-years line is the pack claim, not a promenade promise. BS EN ISO 12944 is for a specified system. This tin does not meet one because the label says rust. If the old film dates from before the early 1980s and must come off, HSE’s lead note applies: no blow lamp, no dry sanding, children kept away. Large removal in a lived-in house is a professional job.

Common questions

Will one 750 ml tin do a garden gate?
Often not, if both faces and the edges are bare and you follow two coats at about 5 m² per litre. The rule of thumb is about 1.9 m² from 750 ml, enough for a short run of railings. Reviews report one tin going further than expected, and a gate that needed another. Buy the second tin before you stretch the first coat thin.
Do I paint the back and the underside?
Yes. Hammerite’s gate article asks for the front, the back and the sides, and the details first. The underside of the bottom bar is where water hangs. Edges of each bar count as sides. If you cannot reach the back, you have a cosmetic face, not a full system.
Is one coat enough if the old paint is sound?
Yes, where a patch test has held for about an hour and the old film is not flaking. Bare metal and rusty metal still want two coats, about 4 hours apart. Sound means the patch did not wrinkle or lift. One heavy coat is not the same thing, because it sags off the corners.
Why does rust come back at the bottom?
Water sits on the bottom rail, and the film there is often the thinnest, because runs pull paint off the edge. The 8-year bullet does not change that. Wire-brush the rail, give it the same two coats as the face, and do not stop 10 mm short of the underside. A bar that stands in water all winter is the wrong job for a DIY one-pack film.
What if the gate is galvanised, not rusty steel?
Stop and use Special Metals Primer before Direct to Rust. The tins here are the ferrous enamel, and Ultima is not in this comparison. A galvanised gate that has already been painted is a different case from bare new zinc. If you can see bright zinc, do not put the black tin on as the first coat.

Related pages

Best metal paint

Metal paint

Metal paint buying guide: a bottle, tin or radiator

How to paint rusty metal with direct-to-rust enamel

Radiator paint vs outdoor metal paint on a hot panel

Sources

Public sources from the research digest, last checked on 22 October 2026. Shelf prices and star lines are the stored amazon.co.uk figures. The price band is this set, not a market average. No listing was lab-tested.

  1. Hammerite Direct to Rust metal paint, smooth finish (retrieved 22 October 2026)
  2. Hammerite surface preparation (retrieved 22 October 2026)
  3. Hammerite: how to paint a radiator (retrieved 22 October 2026)
  4. VOC in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012 (retrieved 22 October 2026)
  5. HSE: lead in paint (retrieved 22 October 2026)
  6. HSE: GB CLP hazard labels (retrieved 22 October 2026)
  7. SteelConstruction.info: standard corrosion protection systems (retrieved 22 October 2026)
  8. Rust-Oleum UK radiator paint (retrieved 22 October 2026)