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Rust converter vs rust paint

Updated: 23 October 2026

You are looking at a small bottle and a tin of black enamel, and both claim to deal with rust. One of them changes the rust and still asks for a colour on top. The other is the colour. By the end you should know which purchase matches a stone chip and which matches a steel gate. The [anti-rust paint comparison](/hub/paints-and-varnishes/anti-rust-paint) holds the prices. Peter F. has not run a salt-spray test. The split follows Hammerite’s UK pages, the Rustins data sheet from August 2017, and the staged amazon.co.uk listings, compiled on 20 October 2026. A qualifying purchase can earn us a commission at no extra cost to you.

You are looking at a small bottle and a tin of black enamel, and both claim to deal with rust. One of them changes the rust and still asks for a colour on top. The other is the colour.

Our top picks

Hammerite Hammerite smooth black 750 ml

Best overall

Hammerite Hammerite smooth black 750 ml
9.4/10about £20.43
View offer
Hammerite Hammerite Kurust 90 ml

Best value

Hammerite Hammerite Kurust 90 ml
9.2/10about £7.20
View offer
Vividye Vividye rust converter 2 L

Alternative

Vividye Vividye rust converter 2 L
8.4/10about £29.99
View offer
On this page
  1. 1.Two different jobs
  2. 2.Kurust and Rustins
  3. 3.The 2 litre black converter
  4. 4.When the colour coat is simpler

Two different jobs

A rust converter reacts with rust still on ferrous metal and leaves a changed surface you then paint. A rust paint in this set is Hammerite Direct to Rust, the colour coat, with a primer and undercoat claim on the black 750 ml tins. Kurust will not give you a gloss black gate. A remover, which dissolves rust, is not staged here. Coo-Var’s UK page still says you should paint over a converter because the film is less durable than a topcoat. Loose flakes come off either way. The buying guide puts pack size on that choice.

Kurust and Rustins

Hammerite Kurust 90 ml, B001C43UO6, is a matt treatment for chips, meant to turn blue-black. Do not pour leftovers back into the bottle. Reviewers see the dark reaction in minutes and say the blister is smaller than expected, runny and messy. One buyer wanted a body colour and received a brick-red liquid. The listing says 0.9–1.08 m² per 90 ml. Hammerite’s Kurust page says 20–25 m² per litre. Do not average those rates, and do not plan a gate from the litre figure. Rustins 250 ml, B077HZW928, is £9.00 with 4.4 from 582 reviews. The August 2017 data sheet keeps it to corroded ferrous metal at about 15–25°C, a blue-black coating and no separate primer. A later product page mentions brass, copper and bronze. Brushes clean in water. The liquid is still not the decorative coat.
Hammerite Hammerite smooth black 750 ml

Testsieger

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

The 2 litre black converter

Vividye, B0GFW542M9, is £29.99 with 4.2 from 50 reviews, a water-based matte black converter and primer, listing origin China. The bullets say light rust at or under 120 μm can be coated directly, severe rust wants loose scale sandblasted off, and you wait at least 2 hours between coats. Some reviewers leave the matte black as the colour they see. The container field says aerosol can. Reviews describe a plastic bag in a bucket and a brush. Waterproof is false. Aluminium and galvanised metal are not established on this ASIN. It is the large water-based black base when 90 ml is a joke.

When the colour coat is simpler

A glossy black steel gate is one system: Hammerite smooth black, two coats on bare or rusty ferrous metal, loose rust off first. The top pick is B0082LTMD0 at £20.43, 4.7 from 7,075 reviews. You do not need Kurust first on light, tight rust. You do need a converter when the pits are severe. The colour coat does not remove rust, and it is the wrong first coat on bare galvanising. The black tins that state a base are solvent enamel, so the brush cleaner is not a water rinse. The how to apply page is the 4-hour recoat and the drain rule. For a whole gate today, the colour coat is the one tin.

Common questions

Is a rust converter the same as anti-rust paint?
No. In this set a converter is Kurust, Rustins or Vividye, and you still overcoat it. Anti-rust paint as a colour is Hammerite Direct to Rust, which is the finish. Shop titles use both phrases for both products. The test is simple: if the tin has no colour you want to look at next year, it is a treatment.
Do I have to paint over Kurust?
Yes, if you want a durable finish. Hammerite says a topcoat after 3 hours. Coo-Var makes the same point about converters in general: the reacted film is less durable than a topcoat. Reviewers in this file do overpaint at about 3 hours. Leaving the blue-black patch bare is not the system the page describes.
What if it stays pale?
Put more on. Kurust says reapply if there is no colour change in about an hour. Rustins says reapply after about 30 minutes if it has not gone blue-black. A pale, yoghurt-like Rustins review is that miss, often with loose rust still in the pit. Do not hide a pale patch under enamel and call the reaction finished.
Is Rustins for aluminium?
The staged bullets say ferrous iron and steel only, not aluminium or other non-rusting metals. The 2017 data sheet agrees on corroded ferrous metal. A later product page mentions brass, copper and bronze. That wider line is not a reason to put this 250 ml bottle on aluminium. If the metal does not rust, this converter has nothing to convert.
Can Vividye be the final black coat?
The bullets say the matte black is a base for topcoats. Some of the 50 reviewers leave it as the colour on gates and railings. One reports peeling and one reports rust after two days, and several say a winter is still unproven. You can look at it as a finish. You cannot claim it replaces a gloss enamel.
Which is the best value for a chip?
Kurust 90 ml at £7.20, 4.6 from 4,655 reviews, then a topcoat. Rustins at £9.00 gives 250 ml when the patch is bigger and the metal is ferrous. A 750 ml enamel is the wrong scale for one chip. Vividye at £29.99 is volume, not a chip bottle.
Will a converter stop rust for years with no topcoat?
Do not claim that. Kurust, Rustins and the Coo-Var explainer all point to a topcoat. One Rustins review saw rust again after a few months. Vividye has a two-day rust-back review inside a sample of 50. The Hammerite eight-year line belongs to the colour-coat range as a maker claim, not to a bare converter.

Related pages

Best Hammerite for rusty metal

Paint a rusty metal gate

Anti-rust paint

Best anti-rust paint UK: colour or a converter

How to paint rusty metal: coats and the cleanup

Sources

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

  1. Hammerite Direct to Rust (retrieved 22 October 2026)
  2. Hammerite Direct to Rust metal paint, smooth finish (retrieved 22 October 2026)
  3. Hammerite Direct to Rust metal paint, hammered finish (retrieved 22 October 2026)
  4. Hammerite Kurust (retrieved 22 October 2026)
  5. VOC in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012 (retrieved 22 October 2026)
  6. HSE OCE2: solvent brush painting controls (retrieved 22 October 2026)
  7. GOV.UK: hazardous waste disposal (retrieved 22 October 2026)
  8. Rustins rust converter data sheet (retrieved 22 October 2026)