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Zinc paint vs hot dip galvanising

Updated: October 2026

A cut slot in a galvanised garden gate, a ground weld on a trailer chassis, or a bracket knocked bare in the van is a familiar job. The aerosol says cold galvanising, which sounds like the molten bath you already paid for. Zinc paint vs hot dip galvanising is the split between a coating you apply and hot-dip galvanising to BS EN ISO 1461. This page says when a can is a small repair and when the article should go back, and the product table is on the [zinc paint](/hub/paints-and-varnishes/zinc-paint) comparison. These notes use public UK technical sources from October 2026, and a qualifying purchase can earn a commission at no extra cost to you.

A cut slot in a galvanised garden gate, a ground weld on a trailer chassis, or a bracket knocked bare in the van is a familiar job.

Our top picks

Action Can Action Can ZG-90 500 ml

Best overall

Action Can Action Can ZG-90 500 ml
9.4/10about £10.77
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Hycote Hycote XUK207 twin pack

Rank 2

Hycote Hycote XUK207 twin pack
8.4/10about £19.12
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Motip Motip M04061 400 ml

Best value

Motip Motip M04061 400 ml
8.8/10about £8.96
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On this page
  1. 1.Two different processes
  2. 2.When a repair paint is in the standard
  3. 3.Sacrificial protection is a requirement, not a slogan
  4. 4.When to send it back

Two different processes

Hot-dip galvanising, in the batch sense a specifier means, is a bath of molten zinc after the steel has been fabricated. The European General Galvanizers Association treats only that process to EN ISO 1461 as complete coverage in molten zinc. Zinc-rich paint is a different coating. It sits on the face you prepared, and it does not rebuild the alloy layers of a dip or reach steel you cannot degrease. Cold galvanising is a trade phrase, not a second bath.

When a repair paint is in the standard

ISO 1461:2022 treats renovation as a limited exception, not as a substitute for the bath. Each uncoated area is not to exceed 10 cm², and the total is not to exceed 0.5% of the article, unless you and the specifier agree otherwise. Beyond that, the route is to regalvanise. Renovated areas need a minimum average of 100 µm, unless another thickness has been agreed. A trade sheet for this kind of aerosol puts one pass at about 30 µm, so the first even grey is not that repair.
Action Can Action Can ZG-90 500 ml

Testsieger

Action Can Action Can ZG-90 500 ml
9.4/10about £10.77
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Sacrificial protection is a requirement, not a slogan

Sacrificial protection means the zinc corrodes before the steel at a thin edge or a small break in the coating. The Galvanizers Association looks for ideally at least 80% zinc by weight in a repair paint. Action Can states that ZG-90 is non-conductive, so that colour-match aerosol is not the sacrificial repair on the maker's own line. Where a sheet mentions C3, ISO 12944-2 C3 means urban or industrial air, or a coast with low salinity, not simply outdoors, and it is not a service life for the patch. Coat building is on the how to apply zinc paint page. Which tin is a colour match, rather than a high dry-film zinc, is in the zinc paint buying guide.

When to send it back

Send the steel back to a galvaniser when the bare area is larger than those limits, when the damage is structural, or when the specification names BS EN ISO 1461 and no repair has been agreed. Paint in the corners can spoil a later dip. A note that also names ISO 12944 is a paint system, not permission to replace the bath with any aerosol. Welds, cut ends and fume sit on zinc paint for welds and cut ends.

Common questions

Is zinc paint the same as hot-dip galvanising?
No. Hot-dip galvanising to BS EN ISO 1461 is a molten-zinc bath after fabrication. Zinc paint covers only the faces you prepare, and it does not recreate that bath. The European General Galvanizers Association treats zinc-rich paint as a different coating. Cold galvanising on a label does not close a specification written to the standard.
When is a can an acceptable repair?
A can fits when the damage is small, from cutting, welding, transport or erection, and the paint can be built to the thickness required. The Galvanizers Association lists brush or aerosol for that limited renovation. It is not a stand-in for dipping the whole article, and it fails if the film is too thin or cannot protect the steel sacrificially.
How small does the damage have to be?
Under ISO 1461:2022, each uncoated area should not exceed 10 cm², and the total should not exceed 0.5% of the article, unless the parties agree otherwise. Past that, regalvanise. A bright cut about the size of a large postage stamp can fit. A long ground-back weld on a chassis rail usually does not.
How thick should the repair be?
Renovated areas should reach a minimum average of 100 µm, unless another thickness has been agreed. One pass on a trade sheet for this type of aerosol is about 30 µm, so a single coat is not that repair. Build the film in further coats. Colour alone does not show whether the average is there.
Does a non-conductive colour-match spray meet a sacrificial repair?
Not where the maker calls the film non-conductive, as Action Can does for ZG-90. The repair has to be capable of sacrificial protection, and a zinc-dust paint is judged from about 80% zinc by mass in the dry film. A colour match can still be right when appearance is the job. It is a different product from a zinc-rich repair paint.
What does C3 mean if a sheet mentions it?
ISO 12944-2 C3 means urban or industrial air, or a coastal atmosphere with low salinity. It is a paint-system environment, not a word for anywhere outdoors, and it is not a measured life for your patch. Read it with the thickness you can actually build. A C3 line does not make an aerosol into hot-dip galvanising.
When do you send the article back to a galvaniser?
Send it back when bare metal exceeds the 10 cm² and 0.5% limits, when the damage is structural, or when the job requires BS EN ISO 1461 and no repair is agreed. Paint over a large area can also obstruct a later dip. If the patch may no longer be small, ask the galvaniser before you spray.

Related pages

Best zinc paint

Zinc paint

Zinc paint buying guide: check film, job and claims

Zinc paint for welds and cut ends on galvanised steel

How to apply zinc paint on clean steel, thin coats

Sources

Public UK sources used for the repair and safety points on this page. Prices, stars and review counts are from the amazon.co.uk listings on 16 October 2026.

  1. Galvanizers Association — Repair of galvanized steel (retrieved 16 October 2026)
  2. Galvanizers Association — Coating repair datasheet (retrieved 16 October 2026)
  3. EGGA — Specification guidance (retrieved 16 October 2026)
  4. Action Can — ZG-90 (retrieved 16 October 2026)
  5. Motip — Zinc spray 04061 (retrieved 16 October 2026)
  6. Institute of Corrosion — Zinc-rich coatings (retrieved 16 October 2026)
  7. VOC in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012 (retrieved 16 October 2026)
  8. HSE — Respiratory protective equipment in bodyshops (retrieved 16 October 2026)