Why preparation matters
Powder coating cannot compensate for oil, loose corrosion, mill scale or an unstable existing finish. Contamination can interfere with adhesion, while an unsuitable surface profile can reduce coating performance. Preparation should therefore be specified as part of the coating system, not treated as an afterthought.
Typical preparation steps
- Inspection to identify the substrate, contamination and existing coatings
- Degreasing or cleaning to remove oil and process residue
- Stripping when an existing coating must be removed before refinishing
- Abrasive blasting or mechanical cleaning when the specification requires rust, scale or coating removal and a controlled profile
- Chemical pretreatment selected for the metal and performance requirement
- Drying, handling and masking controls before powder application
Information the coater needs
Identify the metal, current finish, service history and any sensitive surfaces. Let the coater know about weld residue, laser scale, silicone, cutting fluids, cavities and drainage concerns. Photographs help with an initial discussion, but production parts may still require inspection or a trial before the final process is confirmed.
Preparation and verification belong together
The selected process should connect directly to the final acceptance criteria. Visual inspection, film-thickness checks, cure verification and any specified adhesion or corrosion testing provide evidence that the complete system—not just the colour—meets the project requirement.