Marindec PaintsGuides / Application guide
Priming
When to prime, which primer to select for each substrate, and how to apply it correctly.
When priming is required
Prime whenever:
- Bare metal (ferrous or non-ferrous) is exposed
- The substrate is porous or alkaline (fresh plaster, new concrete)
- The product TDS specifies a primer system
Previously painted surfaces in sound condition may require spot priming only over exposed bare areas — not full system re-priming.
Primer selection by substrate
| Substrate | Marindec primer | Notes |
|---|---|---|
| Mild steel, structural steel, cast iron | FPW15 Red Oxide Primer | Ferrous metals only. Do not apply to aluminium or galvanised surfaces |
| Aluminium, non-ferrous metals | EPS15 Etch Primer | Chemical etch provides adhesion through the aluminium oxide layer |
| Galvanised iron / IBR sheeting | GI Primer | Formulated for zinc-coated surfaces; suitable for new and weathered galvanised steel |
| Concrete / masonry | Consult TDS | Alkali-resistant formulation required for new concrete and plaster |
Applying primer
- Apply at the wet film thickness specified on the TDS
- Ensure even coverage — edges, corners, and welds need particular attention on metal substrates
- Allow to cure fully before topcoating — refer to TDS for touch-dry and recoat windows
- Recoat windows matter: applying topcoat too soon (primer not cured) or too late (primer surface degraded) both compromise inter-coat adhesion
Working on a project like this? Request a quote — same-day turnaround on most requests.