FBE Application & Inspection: Common Challenges and How to Avoid Them

Small mistakes in your fusion-bonded epoxy (FBE) process can cost thousands in repairs, or worse, contribute to catastrophic pipeline failures. Corrosion is the second leading cause of hazardous pipeline failures, and it effects millions of miles of pipelines worldwide. FBE coatings are a powerful tool for protecting these pipelines and related infrastructure from corrosion—but only when applied and inspected properly.

Understanding the most common pitfalls—and how to avoid them—can make the difference between an FBE job that lasts and one that fails. Here are the challenges applicators and inspectors face, and how to avoid them.

Surface Preparation Problems 

The challenge:
FBE is highly sensitive to surface cleanliness and profile. Inadequate blasting, remaining contaminants, or the wrong anchor pattern can lead to poor adhesion and premature failure.

What to watch out for:

• Flash rust or mill scale that reappears before coating
• Over- or under-blasted surfaces
• Oil, grease, or salts left on the surface

How to avoid it:

• Verify cleanliness meets SSPC-SP 10/NACE No. 2 (Near-White Metal Blast Cleaning) standards
• Use surface profile comparators to confirm correct anchor depth (typically 1.5–4.0 mils)
• Minimize time between blasting and coating to prevent contamination
• Test for chlorides using soluble salt detection kits

Incorrect Preheat Temperature

The challenge:
FBE requires the substrate to be heated to a specific range—typically 180–250°C (356–482°F). If it’s too cold, the coating won’t bond. Get the surface too hot, and it may degrade or sag.

What to watch out for:

• Uneven heating across the pipe
• Burnt or discolored epoxy powder
• Poor coating adhesion in low-temp areas

How to avoid it:

• Use calibrated IR thermometers or contact thermocouples to verify temperature
• Preheat evenly, especially on larger diameter or thick-walled pipe
• Follow the manufacturer's technical data sheet (TDS) for exact parameters

Poor Powder Application Technique 

The challenge:
Uneven powder flow, low transfer efficiency, or operator error can cause thin spots, holiday formation, or excess buildup. Each of these opens the door to potential future failure.

What to watch out for:

• Visible thin areas or exposed steel
• Over-applied epoxy leading to sagging or poor cure
• Pinholes or fisheyes

How to avoid it:

• Calibrate electrostatic spray equipment regularly
• Apply powder uniformly using a consistent technique
• Measure coating thickness with magnetic gages to confirm compliance with the spec (typically 14–20 mils for single-layer FBE)

Improper Curing 

The challenge:
If FBE doesn’t cure properly, the coating may remain soft, underperform chemically, or fail prematurely under stress. Sometimes a lack of training causes applicators to skip the manufacturer’s recommendations or not recognize the signs of proper curing.

What to watch for:

• Soft or tacky finish indicating FBE hasn’t cured
• Low hardness readings
• Underperformance in adhesion or chemical resistance tests

How to avoid it:

• Monitor and control post-application cooling and cure times
• Avoid applying FBE when ambient conditions could cause premature quenching
• Perform MEK rub testing or other post-cure validation methods

Inadequate Inspection or Missed Holidays

The challenge:
Even with good application, skipping or rushing inspection can lead to undetected defects. Tiny pinholes, voids, and flaws (known as holidays) may not be visible to the naked eye, but even a single pinhole can allow moisture and contaminants to reach the substrate, initiating the corrosion process.

What to watch out for:

• Incomplete holiday testing
• Lack of DFT documentation
• Missed edge or weld area defects

How to avoid it:

• Use high-voltage holiday detectors appropriate for the coating thickness
• Document DFT measurements per project requirements
• Reinspect all weld repairs, field joints, and complex geometries

Want to Level Up Your FBE Knowledge?
If you’re responsible for FBE application or inspection, training can sharpen your skills and help you avoid these mistakes. AMPP offers a Fusion Bonded Epoxy (FBE): Application and Inspection Level 1 Certification to help you further your career.