The Science of Surface Prep: Why 80% of Coating Failures Happen Before Painting Begins

You’re the one who thinks coating failure happens due to a bad product? Lemme break your myth, failure happens due to poor surface preparation. Before the first drop touches the surface, moisture, rust, improper cleaning, and invisible contaminant touches it, which booms the project.

Why does the surface prep matter?

The surface on which we paint is required to be cleaned first, as the majority of the surfaces are covered with dust particles, moisture, and rust, which can interfere with the paint coating and make it crack, which can lead to the failure of the coating.

Up to 80% of all coating failures are traced to poor or insufficient surface prep. As coatings rely on mechanical and chemical adhesion and unstable surfaces interfere with the bonding.

Improper Prep Can Lead To:

• Peeling or Blistering
• Under-film Corrosion
• Delamination
• Early chalking and Color fading

There are common surface Contaminants and their impact on coating:

• Oil/Greece – It prevents adhesion
• Dust/Chalk – It weak bond layer, which reduces the film integrity
• Rust/Scale – It causes under-film corrosion
• Moisture –  It leads to blistering, hydrolysis, and rust
• Chlorides/Sulfates – It pulls in moisture, which leads to osmotic blistering

What are the ways to prepare the surface?

• Solvent Cleaning (SSPC-SP1): We utilize it in OEM or plant-based settings to reduce oil and grease
• Hand Tool Cleaning (SP2): We employ it in spot repairs to facilitate manual scraping and brushing
• Power Tool Cleaning (SP3): We perform it for medium-dusty surface work to achieve mechanical cleaning
• Abrasive Blasting (SP5/SP10/SP6): This process creates a profile and handles critical work on steel bridges and pipelines
• Water Jetting: This method removes salts and loose material
• Acid Etching: We commonly use it on concrete surfaces
• Laser and Dry Ice Cleaning: We use these methods in high-tech/precision manufacturing

However, surface prep doesn’t just take a technical step; it saves costs, boosts performance, protects reputation, and has a positive impact on businesses. Surface prep extends coating lifespan by 2x-3x, significantly reduces rework costs, prevents costly shutdowns, and meets compliance and client requirements.

Preparing the Surface without understanding the Substrate is of no use, as substrate type matters a lot. Every substrate has different ways to prep, like:

• Steel – It requires abrasive blasting or power tools and is susceptible to rust bloom if left exposed too long after prep.
• Aluminum – soft and needs non-metallic blasting or chemical prep to avoid deformation
• Concrete – It requires PH testing, moisture control, and removal of laitance
• Galvanized Steel – Needs sweep blasting or chemical treatment

Surface profile and anchor pattern are the next important steps, as the correct roughness for mechanical adhesion. Thin Film Epoxy requires 25-50 microns depth, Polyurethane requires 50-75 microns depth, and Heavy-duty epoxy mastic requires 75-100 microns depth. One thing you can keep in mind to avoid the mistake is that over-blasting can create too rough a profile, which may trap contaminants and create coating voids.

Paint and Coatings are not less than art if they’re done right. Good things require good hands and method, and for more such updates and innovation, visit Industrial Front!