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Metal paint buying guide

Updated: 23 October 2026

You are standing in front of a rusty garden gate or a scuffed radiator, and every result says metal paint. Some results are a 30 ml bottle with a brush in the cap. Some are a 250 ml or 750 ml tin of outdoor enamel. A radiator enamel is a third product, and it is not among these seven listings. This metal paint buying guide sorts those three jobs and the pack that can cover each one. The [metal paint comparison](/hub/paints-and-varnishes/metal-paint) holds the prices, stars and review counts. Peter F. updated this page on 23 October 2026 from amazon.co.uk listings. We did not run a lab test. A qualifying purchase through our links can earn a commission at no extra cost to you.

You are standing in front of a rusty garden gate or a scuffed radiator, and every result says metal paint. Some results are a 30 ml bottle with a brush in the cap. Some are a 250 ml or 750 ml tin of outdoor enamel.

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 250 ml

Best value

Hammerite Hammerite smooth black 250 ml
9.2/10about £9.97
View offer
Paintsmiths Paintsmiths gloss black 30 ml

Alternative

Paintsmiths Paintsmiths gloss black 30 ml
8.4/10about £8.79
View offer
On this page
  1. 1.Three products share the name
  2. 2.Metal first, then weather
  3. 3.What the saved prices are really buying
  4. 4.What to leave on the main table

Three products share the name

A chip bottle, a direct-to-rust tin and a radiator enamel answer different failures when the title uses the same words. The two Paintsmiths bottles are 30 ml touch-ups. Gloss black is an enamel with an indoor field. Satin white is water-based and lists metal, plastic and tiles. Both put a brush in the cap and both name radiators without a heat limit. The five Hammerite tins are Direct to Rust smooth enamel for outdoor metal. Smooth means a glossy film, not a hammered texture. Black, white and gold are the colours in this set. Hammerite’s own radiator paint is not among these seven ASINs. Outdoor Direct to Rust is pointed at things that do not get hot, such as a bed frame. If the metal will be warm this evening, read radiator paint versus metal paint before you open a gate tin indoors.

Metal first, then weather

Iron and steel that can rust are the ferrous job these tins are sold for. Bare zinc, aluminium and galvanised steel need Special Metals Primer before Direct to Rust. Ultima is not in this set. Painting a new galvanised gate because the label says metal is the mistake that flakes. A gate, a railing and a bistro set want the outdoor enamel. A hot radiator wants a paint that prints a heat limit, applied cold. The 250 ml black flash point of 32°C is flammability of the liquid, not a temperature the dry film can sit at. A chip is the 30 ml bottle. A panel, a bistro set or a short rail can be 250 ml. A gate or a small garage door points at 750 ml. Brush order is on how to apply metal paint.
Hammerite Hammerite 5158235 smooth black

Testsieger

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

What the saved prices are really buying

The saved shelf prices are £8.79 for each 30 ml bottle, £9.97 for smooth black 250 ml, £9.99 for white and £10.51 for gold. The larger black tins are £20.43 (part 5158235) and £22.00 (part 5092966). A rule of thumb: about £40 per litre at 250 ml, about £27 per litre if the £20.43 tin is 750 ml, and about £293 per litre for 30 ml. The bottle suits a thumbnail mark. Listing fields that run up to 10–12 m² per litre will make you buy too little against the maker’s about 5 m² per litre. Part 5158235 disagrees on fill: the title says 750 ml, the size field says 1 l, and the unit count says 1,000 ml. Who each listing is for is on best metal paint.

What to leave on the main table

The three 250 ml colours share a star line of 4.6 from about 20,430 reviews, and the saved texts repeat other colours. That count is not 20,430 people reviewing gold, white or black alone. The two large black tins both show 4.7. The top pick is the one with 7,075 reviews, not a laboratory winner. Best value is the £9.97 black 250 ml tin, the lowest saved price among direct-to-rust tins of at least 250 ml. The eight-year line is a pack claim, not a coastal guarantee, and a DIY tin is not a BS EN ISO 12944 system. Read the VOC line under SI 2012/1715. Low VOC on the satin bottle has no grams-per-litre figure.

Common questions

Is a small touch-up bottle the same paint as a gate tin?
No. The touch-ups are 30 ml Paintsmiths bottles at £8.79, with partial coverage and a cap brush. The gate objects are Hammerite Direct to Rust tins of 250 ml or about 750 ml. A bottle hides a chip. It will not coat both sides of a steel gate. Match the pack to the failure, then match the colour in daylight.
When is 250 ml enough, and when do I need 750 ml?
At the maker’s about 5 m² per litre, treated as one coat, 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. A bistro set or a short rail can fit the smaller tin. A garden gate, especially both faces and the edges, points at 750 ml, and a second tin is normal if the steel is bare.
Can I use outdoor metal paint on a radiator?
These Hammerite tins are outdoor direct-to-rust enamel. None prints a service temperature. A flash point of 32°C on the 250 ml black bullet is about the liquid catching fire, not a hot radiator. Hammerite’s radiator enamel is a different product, painted cold, and it is not in this comparison.
Does direct-to-rust stick to galvanised steel?
Not as a first coat on bare zinc. Hammerite sends galvanised steel, zinc and aluminium to Special Metals Primer before Direct to Rust. A rusty ferrous gate is the job these tins describe. A new galvanised gate is not. Ultima is not in this set.
What does the eight-year line actually mean?
It is the Hammerite bullet on several of these tins: up to 8 years of rust protection. Part 5158235 says long-lasting corrosion protection and does not print that line. We did not run an exposure test, and it is not a BS EN ISO 12944 category. Edges, the bottom bar and salt air shorten any one-pack film.

Related pages

Metal paint for gates and railings

Metal paint

Best metal paint UK for your garden gate or panels

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)