When the zinc coating on galvanized steel is damaged to a certain extent, the underlying steel can begin to rust. It is crucial to avoid damaging the zinc layer during the cleaning process. If the galvanized layer has already been compromised, it is necessary to perform repairs after rust removal to restore the protective coating and prevent further corrosion.

In this article, we will explore three common types of rust on galvanized steel—white rust, red rust, and pitting rust—and discuss the corresponding cleaning and repair methods for each.

Different Types of Rust On Galvanized Steel

Galvanized steel is susceptible to three common types of rust: white rust, red rust, and pitting rust. White rust typically appears as the first sign of corrosion, and if left untreated, it can eventually lead to the formation of red rust. In cases of concentrated corrosion, pitting rust is more likely to occur.

In the following sections, we will explore how these rust types develop and the impact they have on the integrity of the metal.

Белая ржавчина

White rust is a superficial, powdery corrosion that appears as a white or grayish coating on galvanized steel surfaces.

It forms when zinc reacts with moisture in environments with poor ventilation, commonly occurring during improper storage or initial installation.

While not immediately severe, white rust can degrade the protective zinc layer over time if not addressed promptly.

Red Rust

Red rust manifests as reddish-brown flakes or stains on the galvanized metal, indicating more serious corrosion. It develops when the protective zinc coating is compromised, exposing the underlying steel to oxygen and moisture.

This type of rust signifies significant degradation, leading to accelerated deterioration of the steel structure.

Pitting Rust

Pitting rust appears as small, localized pits or dark spots on the surface of galvanized steel. It results from concentrated attacks by corrosive agents such as salts or acids, which create tiny breaches in the zinc coating.

Pitting rust can undermine the metal’s integrity by penetrating deeper layers, making it a critical issue that requires immediate attention.

Preparation Before Remove Rust From Galvanized Metal

Before starting, clear your workspace to provide ample room for handling tools and materials.

• Choose a well-ventilated area, especially if you plan to use chemical rust removers, to avoid exposure to harmful fumes.
• Wear protective hand coverings, safety eyewear, and a respirator mask to guard against chemicals, dust, and debris.
• Ensure that all required tools, such as brushes, cleaning solutions, and drying cloths, are within reach for a smooth workflow.

How To Remove White Rust From Galvanized Steel?

Tools Needed

• Soft Brushes or Non-Abrasive Scrubbers
• White Vinegar and Naval Jelly
• Spray Bottle
• Clean Clothes or Rags

Пошаговый процесс

1. Initial Cleaning

Use a soft brush to gently remove any loose dirt, debris, or rust from the galvanized steel surface. After that, apply белый уксус или another mild, neutral cleaner to the rusted areas. Let it sit for 10 to 15 minutes, allowing the solution to break down the white rust. Next, use a soft brush или non-abrasive scrubber to gently scrub the treated spots.

Once the rust has been lifted, thoroughly rinse the surface and dry it completely to ensure there is no residue left behind.

2. If White Rust Persists

If some white rust marks remain after the initial cleaning, you can use Naval Jelly. Dilute it to around 5% concentration with water, and apply it to the affected areas. Let it sit for 5 to 10 minutes, allowing the solution to break down the remaining rust. Then, use a soft brush or non-abrasive scrubber to gently scrub the surface again.

As with the first step, rinse thoroughly and dry the galvanized steel completely to remove all residue.

3. Нанесите защитное покрытие (необязательно)

After successfully removing the white rust, consider applying a zinc-rich primer or protective paint to restore the metal’s protective layer. This extra step helps prevent the future formation of white rust and provides long-term protection against further corrosion.

How To Remove Red Rust From Galvanized Steel?

Tools Needed

• Wire Brush or Medium-Grit Sandpaper
• Power Drill with Sanding Attachment (Optional)
• White Vinegar or Commercial Rust Remover
• Naval Jelly
• Spray Bottle
• Clean Clothes or Rags

Пошаговый процесс

1. Initial Inspection and Surface Preparation

Examine the galvanized metal to determine the extent of red rust. Use a wire brush or medium-grit sandpaper to scrub the affected areas, focusing on heavily rusted spots. For extensive rust, employ a power drill with a sanding attachment to efficiently remove corrosion.

2. Apply the Cleaning Solution and Scrub

Once the surface is prepared, spray белый уксус или mild rust remover evenly over the rusted areas using a spray bottle. Let the solution sit for 15 to 20 minutes to penetrate the rust.

Alternatively, Naval Jelly can be used. Dilute it to 5% concentration with water and apply it to the rusted areas. Let it sit for 10 minutes. After the solution has had time to work, use a wire brush или sandpaper to scrub the surface and remove the remaining rust.

3. Rinse, Dry, and Examine

After scrubbing, thoroughly wash the galvanized steel with fresh water to remove any remaining cleaning solution and rust particles. Once cleaned, dry the surface immediately with clean cloths or rags to remove all moisture, especially from joints and crevices where water can accumulate.

Inspect the metal for any remaining traces of red rust. If rust persists, repeat the cleaning and scrubbing process until the surface is fully rust-free.

4. Apply a Shielding Layer

After the metal has dried and is rust-free, use a primer enriched with zinc or a protective coating. This step restores the protective barrier, preventing future rust formation and enhancing the metal’s durability. Adhere to the producer’s guidelines for usage and drying durations.

How To Remove Pitting Rust From Galvanized Steel?

Tools Needed

• Fine Wire Brush or Small Hand Brush
• Abrasive Pads or Steel Wool
• Plastic Scraper
• Rust Remover Gel or Gel-Based Cleaner
• Spray Bottle
• Clean Cloths or Microfiber Towels
• Sealant or Protective Coating

Пошаговый процесс

1. Initial Cleaning and Inspection

Begin by wiping down the galvanized steel surface to remove dirt, grease, and debris. Inspect the metal closely, identifying the pitted areas and assessing the severity of the rust.

2. Apply Rust Remover Gel and Scrub

Apply the rust remover gel directly into the pitted areas and allow it to sit for 10 to 15 minutes to dissolve the rust. After the gel has had time to work, gently scrub the pitted areas with a wire brush или steel wool to remove the dissolved rust. For any remaining rust particles, use a plastic scraper to gently lift them out.

3. Rinse, Dry, and Inspect

Thoroughly rinse the galvanized steel with fresh water to remove any residue from the rust remover and rust particles. Dry the surface completely, paying special attention to the pits. After drying, inspect the surface again for any remaining signs of rust. If necessary, repeat the cleaning process to ensure all rust is removed.

4. Apply Sealant or Protective Coating

Once the surface is clean and dry, fill the pits with a sealant или protective coating to restore the integrity of the metal and prevent further corrosion. Follow the manufacturer’s instructions for curing and application times.

Tips for Removing Rust from Galvanized Steel

Prevent Over-Scrubbing

Excessive scrubbing can wear down the zinc coating or even create scratches that lead to future rust formation. Apply only the necessary pressure and use fine brushes or steel wool where precision is needed.

Apply Protective Coatings Promptly

After cleaning, apply a zinc-rich primer or protective paint to restore the protective barrier and seal the metal. Delaying this step can leave the surface vulnerable to new rust formation, especially in humid or corrosive environments.

Handle Chemicals Safely

Wear appropriate protective gear, including gloves, goggles, and a respirator mask, when handling chemical rust removers. Follow manufacturer instructions carefully to avoid accidents or ineffective treatment.

Address Rust Early

Act quickly when rust is first detected. Early intervention reduces the effort required to clean the surface and prevents the corrosion from penetrating deeper layers of the metal.

Lasting Galvanized Metal

For premium protection against corrosion, Steel Pro Group offers galvanized steel with precisely applied, uniform zinc coatings for superior durability. Our high-quality packaging also ensures your steel arrives ready to perform at its best.

Trust Steel Pro Group for reliable, durable galvanized steel that resists rust and maintains its strength in even harsh conditions. Protect your projects with the steel that’s built to last.