Let’s take a look at steel and other metal primers. Steel is made of iron ore and carbon and other alloying elements. The presence of iron ore naturally makes it more susceptible to corrosion and rust. And that makes it necessary to use steel primers especially for structural steel to take care and protect it from steel corrosion for durability and longevity. Top steel primer brands in India such as Asian Paint, Berger and Nerolac, are renowned for their wide range of metal primers across budgets to cater to diverse protect needs.

We take a look at what are steel/metal primers? It’s purpose, application, and how to select the right primer for your steel. Also, price of steel primers in India and how to buy them.

What is steel primer?

Steel primers are a type of preparatory coating applied to steel metal surfaces before painting. The primer base ensures that the paint is applied evenly and sits better safeguarding the metal from wear, rust and corrosion.

Steel primer vs Galvanised steel

Steel primers are different from galvanised steel.

What is the purpose of steel primer?

We’ve already looked at the meaning of steel primers. Let us now understand the purpose of steel primers or why steel and other metals needs to be painted with primers?

Steel primers are required to preserve the surface of the metal. This is more in case of structural steel and steel used in outdoor settings or coastal areas prone to harsh environmental conditions.

Some of the benefits of steel primers and why they are used are:

• Acts as an adhesive: The main purpose of applying a layer of primer to base metal is to form a cohesive bond between the metal and the topcoat paint. The primer allows the topcoat paint to sit better on steel reducing scope of peeling or flaking.
• Increases resistance to corrosion: Steel corrosion is not uncommon. Applying a layer of steel is an effective way to reduce steel corrosion. The primer ensures the metal is shielded from humidity, heat, and other harsh environmental factors. This naturally extends the lifespan of the metal and the structure.
• Makes steel more durable: Since primers act as a shied for the metal underneath, it increases the durability of the steel. Compared to steel structures without a primer, those with primers lasts longer and requires lesser maintenance.
• Adds aesthetic properties: Steel primers add elegance to raw steel. It can be applied in specific colours and can give the metal surface a smooth and uniform finishing touch. The consistency in appearance and sheen enhances its visual appearance.
• Lowers maintenance cost: The steel metal primer layer acts as a shield, safeguarding the metal from the outside. As such, it faces and withstands environmental elements first without letting the steel get affected. This reduces the need for frequent re-painting or touch-ups, making it a cost-effective solution.

What are the different types of metal primers?

Like steel, other metals such as copper, aluminium and iron can also benefit from using metal primers. To provide the right metal protection, it’s important to understand metal primers and their types. This will enable business owners to take an informed decision when using steel any other metal along with it.

Types of metal primers:

• Red oxide primers: As can be understood by its name, red oxide primers are used to protect metals from rusting. Commonly used in iron and steel when used for outdoor structures and industrial applications. (Also read: Stainless steel rust – How to remove and clean it)
• Acrylic primers: Used commonly as a metal primer, they are quick to dry and provide a smooth surface finish. Acrylic primers are used mostly in DIY projects or those that have light use.
• Zinc chromate primers: A popular choice for metal primers in humid and costal areas, these provide protection against corrosion. They are usually used on aluminium and light metals.
• Galvanised metal primers: This is a special type of metal primer, used for galvanised products and zinc-coated metals. The purposed of galvanised metal primers is to ensure that the topcoat paint adheres easily to the metal which is otherwise often difficult to paint.
• Epoxy-based primers: A popular primer for iron and steel, these safeguard the metal from corrosion and enhance durability.

What are metal primers used for?

Metal primers safeguard the metal from corrosion, rust and wear. By doing so, it also prepares the metal for painting ensuring that the paint is able to spread uniformly across the metal and sit tight.

For instance, when steel or iron metal is being used for making iron or steel railings, a layer of metal primer will act as a protective shield and prevent quick corrosion. It will also enhance its aesthetic appeal. If the railing already has some rust on it, a layer of zinc chromate primer can be applied to seep through the rust and prevent the metal from further damage. (Also read: Steel railing designs for balconies – Safety, style and durability)

Metal primers also increase the durability of the metal, especially in areas that’s prone to harsh weather conditions, e.g., heat, humidity, saline, etc.

Is a primer required for all metals?

It is always recommended to use a primary metal primer before painting or coating. It prevents rusting as it forms an adhesive base for the paint to stick without flaking.

This is more so for metals like steel and aluminium. If the metal surface is new and clean, a basic layering of primer will suffice. However, if the surface already has some irregularities or is rusted, a primer layer is a must.

Also, the material of the paint and the natural elements the structure will be exposed to also impacts the decision to use a surface metal primer. (Also read: What are ferrous metals?)

What is the best primer for structural steel?

We have looked at the different types of metal primers and what are its best applications. Let’s now look at the best primer for structural steel.

Structural steel products are used in construction and infrastructure development projects. As such, it is important to choose the right primer for structural steel for durability and longevity. Some of the recommended types of structural steel primers are:

• Epoxy-based primers: Suitable for stainless steel, carbon steel and mild steel. They form a strong bond with the metal surface and safeguard the metal against corrosion.
• Zinc-rich primers: These are suitable for structures used in marine and harsh environmental conditions as they provide cathodic protection.
• Polyurethane primers: For general purposes, providing balance between forming a protective layer and adding elegance and smoothness to the surface.

How to apply steel primer?

In this section we will understand how to apply a primer to your steel metal surface. In general, different methods can be used such as using a spray can or spray gun, brush or roller.

Steel primer application process:

• Prepare the steel: Check the surface for paints and unevenness. Scrape off any paint peels and clean the surface of rust, grease and dirt.
• Smoothen the surface: Use a sandpaper or any tool to clean and smoothen the surface and rub off any residue. Also, sanding cleans the surface but adds a roughness to the steel which helps the primer to sit better. Next, clean the surface.
• Apply the primer: You can apply the primer with your preferred tool – spray brush, roller or can. Ensure this is done evenly without any pooling, spilling and dripping.
• Allow it to dry: Set the metal aside and let it dry. Depending on the weather, location and type, it can take from a few hours to 2 days for the primer to dry completely.
• Give a second coat: A second layer of primer can be applied, especially when the metal usage is in humid environments. This is optional. Also, if using oil-based paints for topcoat, a double primer layers are recommended.

Pro tip: When applying metal primers, ensure you are wearing masks, gloves and the recommended protective gear for safety.

What’s the price of steel metal primer in India?

When budgeting for primers, it’s advisable to understand the price range of steel primers in India. Let’s take a look at them:

How to select the right steel primer?

By now you understand the importance of steel primers and why it is important to choose the right primer for ensuring the integrity of steel and durability of the project. Here are some things to keep in mind when selecting the right primer:

• Metal type: This is important. For instance, primer for stainless steel will be different from carbo steel and even aluminium.
• Condition of steel: Check the condition of the steel you are using and select the primer accordingly.
• Nature of the project: This refers to the environment or location of the project. For marine and coastal areas, use primers with high corrosion resistance abilities.
• Compatibility: The primer is only a layering for the final topcoat paint. Ensure the two are compatible.
• Application: Primers can be applied using various methods. Choose a primer that fits your method of application.
• Cost of primer: Check the price of the primer and ensure that it fits your budget requirements.

Author: Sohini Banerjee

Sohini is a seasoned content writer with 12 years’ experience in developing marketing and business content across multiple formats. At Tata nexarc, she leverages her skills in crafting curated content on the Indian MSME sector, steel procurement, and logistics. In her personal time, she enjoys reading fiction and being up-to-date on trends in digital marketing and the Indian business ecosystem.