Complete Guide to Container Anti-Corrosion Coating Process: Eight Steps to Long-Term Rust Protection

Created on 07.27

For containers that are constantly exposed to outdoor and marine environments, the greatest loss is often not physical wear and tear, but chemical corrosion. Salt spray, UV radiation, rain immersion, and temperature fluctuations continuously challenge the container's protective coating. A professional and complete anti-corrosion coating system is essential for ensuring long-term value retention and structural safety.

Why Do Containers Need Professional Anti-Corrosion Treatment?

As steel structures fully exposed to outdoor, high-salt, and high-humidity environments, containers face four major corrosion factors:

Salt spray corrosion

: Chloride ions in marine and coastal environments penetrate the paint film and corrode the steel plate from within.

UV degradation

: Prolonged sun exposure causes the topcoat to chalk, crack, and lose gloss.

Condensation and moisture

: Water pooling at corners, welds, and the bottom edge leads to localized pitting and rust streaks.

Vibration-induced cracking

: Continuous vibration during transport and lifting can cause ordinary paint films to become brittle and crack.

Given these severe conditions, quality containers use a three-layer anti-corrosion coating system (primer + intermediate coat + topcoat), rather than a simple two-coat spray.

The Three-Layer Structure of a Standard Anti-Corrosion System

Each layer has a distinct and essential function:

Primer (Rust Prevention & Base)

Intermediate Coat (Thickening & Sealing)

Topcoat (Weather Resistance & Protection)

The Eight-Step Standard Application Process

Container anti-corrosion work follows the principle: "70% surface preparation, 30% painting." The complete standard process is:

Surface Cleaning

: Thoroughly remove oil, dirt, old paint, welding slag, and other impurities to ensure a clean surface.

Rust Removal and Grinding

: For new containers, use sandblasting to achieve Sa2.5 (the highest standard for industrial heavy-duty anti-corrosion). For refurbished containers, use mechanical grinding combined with rust removers to completely eliminate scale and loose rust, revealing a uniform metallic sheen. This is the most critical step for the coating's lifespan.

Dust Removal and Drying

: Use high-pressure air and clean cloths to remove grinding dust, ensuring the surface and steel temperature meet requirements (humidity below 85%, steel temperature at least 3°C above the dew point).

Application of Epoxy Zinc-Rich Primer

: Apply using airless spray equipment. Follow the "thin coats, multiple passes" principle, with extra thickness applied to corners, welds, and bottom edges. Standard dry film thickness: 30-50μm.

Application of Epoxy Micaceous Iron Oxide Intermediate Coat

: Apply after the primer has fully cured (12-24 hours at room temperature) to seal minor imperfections and improve impact resistance. Standard dry film thickness: 40-60μm.

Local Spot Filling and Sanding

: After the intermediate coat dries, perform fine sanding on any runs, particles, or uneven areas to create a smooth base for the topcoat.

Application of Weather-Resistant Topcoat

: Apply two thin coats to ensure uniform color, full gloss, and complete coverage without misses, sags, or orange peel. Standard dry film thickness: 40-60μm.

Full Curing and Maintenance

: After spraying, allow the unit to cure at room temperature for 72 hours to achieve final hardness, adhesion, and anti-corrosion properties. Protect from rain, impact, or stacking during this period.

Common Process Pitfalls to Avoid

The following shortcuts significantly reduce container lifespan:

Omitting the intermediate coat – results in a thin film that is easily chipped, leading to rapid rusting.
Inadequate rust removal – residual rust continues to spread under the paint, causing blistering and peeling.
Using non-heavy-duty anti-corrosion paint – cannot resist salt spray and UV, leading to rapid chalking and fading.
Applying a single thick coat – causes sags, improper curing, and blistering, resulting in widespread film failure.
Painting in poor weather – application in humid or low-temperature conditions severely compromises adhesion.

Our Practice and Commitment

As a professional supplier of containers and specialized units, we strictly follow the heavy-duty anti-corrosion coating standards outlined above. Every container we deliver or refurbish follows the complete process:

Surface Cleaning → Mechanical Rust Removal → Dust Removal & Drying → Epoxy Zinc-Rich Primer → Epoxy Micaceous Iron Oxide Intermediate Coat → Fine Sanding → Polyurethane Weather-Resistant Topcoat → Full Curing & Maintenance

Standard Total Dry Film Thickness: 110-130μm

Expected Service Life: 5-8 years in outdoor environments without major rusting, peeling, or chalking (varies with specific conditions)

We understand that professional anti-corrosion treatment is the foundation for durable, value-retaining, and safe containers. Whether for new manufacturing, old container refurbishment, or specialized units for energy storage or modular conversion, our commitment to every step of the coating process is to provide long-lasting protection for your investment.

ACE Container and Parts Co., Limited is a professional supplier of shipping containers and container parts. We were founded in 2011 and located in Tianjin, China. There is Xingang Port, the largest port in North of China. About 60km far from Beijing International Airport.

We are the No.1 shipping container supplier. We can provide One-Stop shipping container solution for customers. We have obtained ISO9001 and SGS certificate. We can provide shipping containers with CCS, BV, LR, DNVGL Certificate.