Summary: In epoxy thick film, glass flakes overlap like fish scales, lengthening the diffusion path of corrosive media — the core shielding for scrubbers, tanks and waste-water linings.
Mechanism
Flakes (tens to hundreds of microns) lie parallel to the substrate, forcing media along a long tortuous path; the epoxy binds and resists chemicals.
Key data
- Finer, higher flake loading = longer path, but too fine hurts leveling; loading often ~20-35% by volume.
- To avoid sag/bubbles, total DFT (often ~500-2000 µm) is built in multiple coats.
- Intercoat flash/gel time must be controlled to release bubbles; humidity and dew point must be managed.
- Vinyl ester lifts acid and temperature resistance above standard epoxy.
Selection by type
| System | Acid/heat | Use |
|---|---|---|
| Bisphenol-A epoxy | Good chemical, mid-temp | Tanks, waste-water |
| Vinyl ester | Strong acid, higher temp | FGD / strong acid |
Defects & fixes
- Bubbles in thick film: divide coats and use de-airing roller.
- Missed spots: spark-test after cure.
- Corners/welds: pre-fill putty plus glass-fiber tape.
FAQ
Why does glass flake stop corrosion?
Overlapping flakes create a maze-like diffusion path, greatly slowing media penetration.
Why do bubbles form in thick coats?
A single very thick coat traps solvent/air; apply in multiple coats with flash between.
ISO 12944 corrosion protection and coating-thickness grading; flake-lining application and pinhole testing (public standards).
Kexin New Materials (Guangdong) Co., Ltd. · 2026-09-17