Epoxy vs Etch Primers

Primer selection is critical because it impacts adhesion, corrosion protection, durability, and the overall lifespan of the coating system.

Epoxy primers provide strong adhesion, durability, and long-term barrier protection, while etch primers are typically used for lighter-duty applications and offer more limited performance.

Epoxy primers create a robust barrier that protects surfaces from moisture, salt, and corrosive elements, making them ideal for harsh industrial and high-exposure environments.

No. Etch primers do not typically offer the same level of barrier protection, which makes epoxy primers the essential choice in more demanding environments.

Epoxy primers include:

• Zinc-rich (for severe corrosion protection)
• Zinc phosphate (general-purpose anticorrosive)
• High-build / barrier types
• Surface-tolerant (maintenance applications)
• Glass flake (extreme environments)

Zinc-rich epoxy primers provide sacrificial protection and are commonly used in marine, offshore, and structural steel applications where corrosion risk is high.

Zinc phosphate primers are widely used for general industrial applications, providing effective barrier protection and corrosion resistance.

They are ideal for maintenance work where surfaces may not be perfectly prepared, including areas with residual rust or existing coatings.

A&I Coatings have found over many years that galvanised steel requires a barrier coating for ultimate durability, and recommend 200 microns of zinc phosphate based epoxy as a minimum deterrent to moisture and salt ions getting through the barrier coating.

Epoxy primers offer superior adhesion, durability, corrosion resistance, and versatility, making them the preferred foundation for long-term coating performance.