Steel without anti rust paint for metal rusts

Anti rust paint for metal protects & extends lifespan

Anti rust paint for metal acts as a barrier between a metal and its environment, increasing its durability and lifespan. The estimated global cost of metal corrosion damage is billions of pesos. The good news is, a lot of this loss can be prevented by being proactive, and choosing the right anti rust coating from the start.

To determine the right anti corrosion coating for your project, it is important to factor in the environment and type of metal. Whether corrosion is due to moisture, chemicals, salt spray, or oxidation, anti rust coating for steel and metal can help protect the substrate from the elements.

Anti rust paint for metal comes in a great variety and versatility

Anti corrosion coating is essentially a collective name for various types of coatings that protect a substrate from corrosion. An anti corrosion paint can do more than just protect from corrosion, and its multi-functional nature means you can find the exact coating you require. Corrosion is caused by a chemical reaction between a metal and its environment (water or other fluids), typically producing an oxide or a salt of the original metal. The long and the short of it is the metal is weakened, as is the structure it creates. An anti rust paint for metal prevents direct contact between water/fluids and the steel substrate and therefore prevents the corrosion process.

In general anti corrosion coating is suitable for almost any type of steel and metal, and has the following benefits:

  • Repels water & other fluids (in case of barrier coatings)
  • Fends off fungi, algae, and moss
  • Weather protection against acid rain,  salt water, ice and so on
  • Chemical resistance
  • Additional characteristics (anti slip, acid resistance etc.) depending on your needs

Corrosion category – the first idea of the best anti rust coating

To determine the right types of anti corrosive paints for your project, you need to understand the environment and use of the substrate. Particularly its exposure to water, moisture, and other aggressive substances that might be present in the environment. The corrosivity of certain atmospheres has been classified and standardised by the International Organisation for Standardization. The standard divides the degree of corrosivity into 5 categories , C1 to C5, in order of increasing corrosivity. To find the right anti rust paint for metal, you need to know how corrosive the environment will be. For example, a coating at C5M level is intended for offshore constructions which are constantly exposed to moisture, but also for small pipes that are equally exposed.

Corrosion CategorySuitable forExamples
C1 – very low corrosion riskHeated buildings with clean air, interiors onlyOffices, schools, hotels, shops and other heated premises
C2 – low corrosion riskUnheated buildings, rural areasStorage facilities, sports halls, garages, barns and other unheated buildings
C3 – moderate corrosion riskBuildings with high humidity, urban and industrial areasLaundries, breweries, kitchens, food processing sites and other buildings with moderate humidity
C4 – high corrosion riskChemical manufacturers and swimming baths, industrial and coastal areasIndustrial buildings, chemical plants, swimming pools, ports, and ship- and boat yards
C5 – very high corrosion riskBuildings with almost permanent condensation, offshore and industrial areasWater pipes and other industrial applications (C5I – industrial). Offshore and maritime constructions (C5M – marine)

Once you have identified your environment, you can identify the right anti rust paint for metal in your project and the right anti rust coating specification to protect it for years to come. Following these guidelines will allow you to pick appropriate anti-corrosion coatings, allowing you to avoid overspending on unnecessary degrees of protection or simply making the wrong choice.


The 3 types of anti corrosive paints for industrial steel protection

Anti corrosion coating types can be divided into three categories:

  1. Barrier coatings for C1 – C3 – non-porous anti rust coatings designed to prevent corrosive factors coming into contact with the substrate.
    For example: powder coating, polyurethane paint, chloro rubber paints, Teflon coatings, nano coatings.
  2. Inhibitor coatings for C1 – C4 – anti rust treatment which releases a chemical that interferes with the electrolyte and stops the corrosion process.
    For example: all oil based coatings with corrosion inhibitor additives such as zinc, aluminum, zinc oxide and so on.
  3. Cathodic protection for C3 – C5 – metal-rich anti rust coating for steel which provide a sacrificial layer. Prevents corrosion by providing a more easily corroded metal (such as zinc) to be the anode to the protected metal’s cathode. Also called the sacrificial anode, this metal will corrode instead of the protected metal.

Anti rust treatment by dipping or spraying

applying corrosion resistant coating by galvanizing

Galvanising is a common method of priming steel for anti rust paint for metal.

The two most common methods for applying a industrial grade metal anti corrosion coating are hot dip galvanisation and thermal (metal) spraying:

  1. Hot Dipping is the process of immersing a metal in a bath of metal, often molten zinc, in order to form a coating. The liquid metal bonds to the substrate and forms an alloy, which is then coated in zinc as it is removed from the bath. Hot dip galvanising uses the principle of cathodic protection, as the zinc coating acts as an anode to its substrate.
  2. Thermal (metal) spraying applies zinc or aluminium to a substrate by taking the metal in the form of a powder or wire and feeding it into a special spray gun. The metal is melted within the gun and can then be sprayed onto the substrate. It does not alloy, but instead works by coating the surface in overlapping metal platelets.

The best anti rust coating for steel is a duplex system

When hot dip galvanising is used together with a topcoat of anti corrosion paint or powder it is known as a Duplex System. The duplex systems are applied as anti rust coating for steel and occasionally other metals.

This type of anti rust treatment provides multiple types of protection and the longest-lasting results. Each layer needs to be compatible in order for the system to work effectively. Duplex anti rust coating systems are especially suitable for corrosion categories C3 to C5,  and it consists of the following 5 steps/ layers.

  1. Surface preparation: derusting, blasting, removing grease, oil, dirt for optimum adherence.
  2. Hot dip galvanisation OR applying an inhibitor coating primer depending on the coating system of your choice.
  3. Applying a sealer: To seal the anti corrosion coating. Often epoxy based.
  4. Intermediate coat: several layers may be necessary for optimum protection, depending on the corrosion category and the chosen anti rust paint.
  5. Finishing coat: provides appearance and surface resistance, often first line of defence.

Corrosion resistant paint products in the Philippines

Here is a selection of products on the market in the Philippines to give you a rough guide as to the price of anti corrosion paint. Keep in mind that for categories C4 and C5 it is not recommended to apply the anti corrosion coating yourself. Please search out a specialist in that case.

PRODUCTAnti corrosion coating TYPECorrosion Category
Jotun Jotamastic 90Barrier coating: Epoxy coating for above and below water, on concrete or steel, with abrasion and chemical resistance.C1 – C3
Jotun Barrier 90Inhibitor coating: Zinc-rich epoxy containing 90% zinc. Suitable for above water and on steel, with abrasion and water resistance.C1 – C4
Hempel GalvosilCathodic protection: two-component, solvent-borne, self-curing, inorganic zinc silicate with outstanding resistance against weathering and abrasion.C3 – C4
Hempel HempadurGalvanising coating: two-component, epoxy based. It cures to a flexible, well-adhering coating with good abrasion and impact resistance. Contains zinc phosphateC3 – C4
Ultrimax 1Inhibitor coating: Contains zinc phosphate anti-corrosive properties and a high volume of solids. C1 – C3

If you are looking for a professional company to apply the anti corrosion coating for you, it’s important to understand how prices are established before you request a quote. Cathodic protection pricing is usually based on the weight of the parts before and after galvanising. Powder and liquid coatings are usually charged per square metre (surface area). For more information about anti rust paint for metal products, services and manufacturers, feel free to contact us! Our experts are here to help.


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