Etch primers

Etch primers are a type of primer used in painting and surface preparation, particularly on bare metal surfaces. They contain acidic chemicals (usually phosphoric acid) that "etch" or slightly corrode the metal surface to improve adhesion. Etch primers also contain a small amount of zinc phosphate or similar corrosion-inhibiting pigments to provide basic rust protection.

Key Features of Etch Primers:

• Excellent adhesion to non-porous surfaces like aluminium, galvanised steel, and mild steel.
• Corrosion resistance due to the inclusion of anti-corrosive pigments.
• Thin application – usually applied in a light coat.
• Fast drying – allows for quicker topcoating.
• Not a build primer – typically followed by a high-build primer or undercoat before topcoating.

Common Uses:

• Automotive refinishing
• Industrial and commercial metalwork
• Domestic painting projects involving metal surfaces
• Pre-treatment for powder coating

Important Notes:

• Etch primers are usually not suitable for plastic or wood.
• They may require a topcoat or further priming for long-term durability.
• Always follow the manufacturer's instructions regarding compatibility with topcoats.

In Australia, etch primers are commonly used by professional painters and contractors to ensure long-lasting paint adhesion on metal substrates exposed to harsh environmental conditions.