How to Repaint Container Houses

Repainting container houses requires following a standardized process, covering construction preparation, substrate treatment, coating application, drying and curing, while paying attention to environmental protection and safety considerations. The specific steps are as follows:

1. Construction Preparation

• Drawings and Standards: Familiarize yourself with the container structure drawings and clarify the painting process requirements and quality standards.
• Material Selection: Purchase paint materials that comply with national standards, such as epoxy zinc-rich primer (for rust prevention), epoxy mica iron intermediate coat (to enhance adhesion), acrylic polyurethane topcoat (with excellent weather resistance), or single-component acrylic topcoat (convenient for application), and prepare matching thinners and curing agents.
• Equipment Commissioning: Equip with high-pressure airless sprayers, air compressors, sandblasting and rust removal equipment, paint film thickness gauges, etc., to ensure normal equipment operation.
• Site Layout: Choose an enclosed or semi-enclosed workshop, divide it into sandblasting, painting, and drying areas, and install a forced ventilation system to reduce the accumulation of harmful gases.

2. Substrate Treatment

• Surface Cleaning: Use solvents to clean oil stains and dust, and dry the surface with a clean cloth or airflow; if there are corrosive substances, thoroughly clean them with sandpaper or a wire brush to ensure the surface is dry and free of grease.
• Sandblasting and Rust Removal: Use sandblasting to achieve a rust removal grade of Sa2.5 (no visible oil, dirt, oxide scale, etc. on the steel surface), and control the surface roughness within 50-80μm to enhance coating adhesion.

3. Coating Application

• Primer: Apply epoxy zinc-rich primer using high-pressure airless spraying to cover the interior, exterior, and underframe of the container. Since zinc-rich paint has a high zinc powder content, stir continuously throughout the process to prevent sedimentation.
• Intermediate Coat: For epoxy mica iron paint, use automatic spraying for the roof and side panels, and manual spraying for the front end and door panels. Adjust the paint viscosity to 20-45s and the pump pressure to 0.3-0.5MPa, and pre-coat the edges before application.
• Topcoat:
  • Single-component acrylic topcoat: Open the can and stir evenly before application. It supports airless spraying, rolling, and brushing, and is suitable for batch renovation or local touch-up scenarios.
  • Acrylic polyurethane topcoat: Apply in the same manner as the intermediate coat, adjust the viscosity to 50-70s, and refer to the intermediate coat requirements for pump pressure and other parameters. It has excellent weather resistance.

4. Drying and Curing

• Intermediate Coat: After application, let it stand for 10 minutes to allow the solvent to evaporate, then transfer it to a drying oven with a temperature controlled at 30-50℃ for 15 minutes to ensure thorough drying.
• Topcoat: The single-component acrylic topcoat has a surface drying time of ≤30 minutes and a full drying time of ≤6 hours at 23℃; the drying of the exterior topcoat should be synchronized with the drying of the intermediate coat, interior topcoat, and zinc-rich primer, strictly controlling the drying oven temperature and time.

5. Precautions

• Environmental Requirements: Choose low-volatile organic compound (VOC) environmentally friendly paint cleaners and thinners to reduce harm to the environment and human health.
• Waste Disposal: Dispose of waste paint and cleaners in accordance with hazardous waste management regulations to avoid contaminating soil or water sources.