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Zinc Powder Coating

Zinc powder coating is an anti-corrosive primer, designed to protect steel substrates.

Used in a two-coat system, zinc powder coating forms a resilient base layer.

For exterior use, you will need to then apply a second layer which will be a polyester powder coating.

Zinc powder coating has these main benefits:

Resistance to corrosion and chemicals

Excellent surface wetting and adhesion to substrates

You can paint over it with different intermediate and surface coats without sanding

Strong and long-lasting performance

What is zinc powder coating made of?

Zinc powder coating is zinc-rich. That means it has a metallic zinc content above a certain level.

It is a form of epoxy zinc paint where, besides zinc, there are two key elements; epoxy resin and a hardener.

Epoxy has a proven chemical resistance which makes it ideal for sealing steel, concrete and other industrial materials.

Zinc powder may be applied as a stand-alone coating, but only for internal use, but typically it works as an undercoat, providing additional protection from corrosion beneath a topcoat.

Why is zinc effective against corrosion?

  • Zinc forms zinc patina, which is a by-product of the metal that acts as a protective barrier when applied to metal surfaces.
  • This barrier keeps out the moisture which can speed up the corrosion process. That is because zinc corrodes significantly more slowly than other metals.

Normally, oxidation occurs when steel or iron come into contact with moisture in the air. Those metals are especially prone to oxidation, which causes corrosion.

A zinc powder coating will act as a metallic barrier, preventing moisture from reaching metal surfaces.

As well as through exposure to the outside elements, corrosion can occur in many industrial environments, through ventilation ducts and in the atmosphere itself where certain chemicals are in use.

By applying a zinc powder coat, you create a durable finish that supports steel surfaces in resisting the effects of corrosion.

How do you prepare a surface for zinc powder coating?

Pre-treatment for various surfaces before applying a zinc powder base coat involves sandblasting.

It is important to remove any foreign substances attached to these surfaces and any metal defects, such as indentations or tool marks. These indentations can cause paint defects if you do not remove them first.

Sandblasting also improves adhesion when the zinc powder layer is applied.

Once you have thoroughly prepared the surface, you can then apply the zinc powder coating.

How do you apply zinc powder coating?

You apply a zinc powder coating polymer using a spray gun, which creates an electrostatic charge that makes the powder particles stick to the surface material.

After this spraying process, the coated material is placed in a curing oven where the heat will help the sprayed coating adhere chemically to the substrate.

The heat creates molecular changes in the zinc powder coating, creating a tough, durable shell.

Why use zinc powder as an undercoat?

A multi-coat system for coating substrates helps bolster protection against corrosion.

Corrosion will strike at weak points in a coating system, and will exploit those aspects where a design is weakest such as:

  • Poor air circulation
  • Corners and sharp edges
  • Unsealed hollow sections
  • Depressions and crevices
  • Ledges

Even the most expertly fabricated parts are likely to have sharp edges, for example, that are weak points.

A multi-coat system, using zinc powder coating as a base, will provide a higher level of protection at these sharp edges and other intrinsically weaker points in a fabrication.

Applying an undercoat will help protect against corrosion, provide good mechanical and chemical resistance and supply a resilient base layer upon which you can then apply a topcoat of your choice.

Are there economic and environmental benefits?

Zinc powder coating is a low-density primer for anti-corrosion, which means it you can apply it easier, and optimise the sustainability of your materials.

Reducing wear and tear, it extends the natural lifecycle of substrates in constant use, providing a cost-effective solution that support increased productivity.

Epoxy anti-corrosion primers are also exempt from labelling requirements for hazardous substances, and powder coatings emit zero or near-zero volatile organic compounds.

Find out more about zinc powder coatings

For more information about the outstanding protection properties of zinc powder coatings, contact Tomburn.


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Zinc Powder Coating

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Tomburn European Offices

  • LBL Finishers (LBL Finishers)
    +44 2392 692 020 | +44 2392 670 379 | Email Us

  • Tomburn CZ s.r.o (Tomburn CZ)
    +420 517 070 841 | +420 516 412 170 | Email Us