anti corrosion paint failure

A complete guide to choosing the right anti corrosion paint

Anti corrosion paint 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 dongs. 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 paint 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.

Here we will provide you with a step-by-step guide to choosing the anti corrosion paint that best suits your project. 

Step 1: Determine the environment of the anti corrosion 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 corrosion paint, 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 treatment for 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.

Step 2: Define the type of anti corrosion paint for the category

anti corrosion coating for steel beams was needed

Anti corrosion paint is crucial on steel beams to let the steel maintain its strength for longer.

Anti corrosion paint types can be divided into three categories:

  1. Barrier coatings (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 (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. Galvanic coatings/Cathodic protection (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 paint by dipping or spraying

The two most common methods for applying a industrial grade metal anti corrosion paint 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.

Step 3: Identify the type of corrosion the anti rust coating must protect from

Whether you are looking to protect a new steel or other metal surface or repair an already rusted one, it is important to be aware of the different types of corrosion. Not every anti corrosion paint protects from the same type.

CORROSION TYPEEXPLANATIONAnti corrosion coating solution
General attackAlso called uniform attack corrosion, the most common form of corrosion. Hence the name. It causes the object to be entirely exposed to the rust.Barrier and inhibitor coatings, cathodic protection
GalvanicTriggered when two metals of different electrode potentials come in contact with each other in presence of an electrolyte such as saltwater. As a result metal ion flow from the more active material to the less active one speeding up the corroding of the more active metal.Barrier coating, cathodic protection
PittingOccurs when a hole forms in the metal. It occurs when a tiny part of the metal loses its protective layer, and becomes exposed to corrosive factors. May be difficult to detect because small size of the holes.Inhibitor coating, cathodic protection
CreviceSimilar to pitting corrosion. Because corrosion happens at a specific location.Minimising the tight spaces in design and applying barrier or inhibitor coatings or cathodic protection

Step 4: Choose an anti corrosion paint product

Here is a selection of products on the market 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 paint for you, it’s important to understand how prices are established in Vietnam before you request a quote. Hot dip galvanising prices are usually calculated by weight. The galvaniser will quote a price per tonne, and then use the weight of your steelwork after galvanising to calculate the final cost. Unlike galvanising, powder coating prices tend to be calculated by size or surface area. Regional differences in materials, labour, and equipment can all have an impact on overall costs when contracting an anti rust coating expert. Contact us for more information or getting in touch with a specialist!

Extra: Anti corrosion coating manufacturers in Vietnam

Here below we provide you with a list of anti rust coating manufacturers who are present in the Vietnamese market.

Anti corrosion paint manufacturerAddress in Viet Nam
Jotun Paints (Vietnam) Co., Ltd.Số 1, Đường 10, KCN Sóng Thần 1, Dĩ An, Bình Dương
Hempel VietnamTam An, Long Thành District, Dong Nai, Vietnam
PPG Yung Chi Coatings Co. Ltd.Unit 604, Fl. 6, REE tower, 9 Doan Van Bo st., dist. 4 Ho Chi Minh City, 84
International Paint Singapore Pte Ltd (Vietnam branch) W15 District 11 Floor 17, Flemington Tower, 182 Le Dai Hanh Street, Ho Chi Minh City, Tan Binh District 70000
Klumpp Coatings VietnamKlumpp Coatings Vietnam Co., LTD, 46 Giang Van Minh, An Phu award, District 2, Ho-Chi-Minh-City 700000


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