Marindec PaintsAll three protect steel, but they cure differently and suit different jobs. Quick-dry enamel is a single-pack alkyd that dries in air within minutes. 2K polyurethane and epoxy are two-pack coatings that cure by chemical reaction once the base and hardener are mixed. They are slower, but give a much tougher film.
Side by side
| Quick-dry enamel | 2K polyurethane | 2K epoxy | |
|---|---|---|---|
| Marindec product | Fast Dry Enamel (39 series) | Polyurethane UHB 7:1 (60 series) | Armourpoxy75 primer (23 series, on request) |
| Packs | Single pack | Two pack, 7:1 | Two pack, 4:1 |
| Film per coat (DFT) | 20–45 µm | 35–45 µm | 70–125 µm |
| Touch dry at 23°C | ~10 min | ~3 h | ~4 h |
| Hard dry at 23°C | ~4 h | ~8 h | ~8 h |
| Overcoat | Within 2 h | After 6 h minimum | After 8 h minimum |
| Strength | Speed, easy application, wide colour range | Extremely durable, very good weathering and gloss retention | Tough, abrasion resistant; very good resistance to acid and alkali spillage and fumes |
| Typical role | Topcoat for machinery, steelwork, equipment | Exterior topcoat for long-life finishes | High-build primer or intermediate coat |
Quick-dry enamel: when speed matters
For workshops, OEM production and dipping lines, a fast-dry alkyd enamel is hard to beat. Parts can be handled within minutes and recoated within 2 hours, and it goes over FPW15, ZPPW15 or etch primer. The trade-off is lower chemical and abrasion resistance than a two-pack, and gloss fades sooner in strong sun. Recoat inside the window, or it can wrinkle.
2K polyurethane: when the finish has to last outdoors
Marindec's 2K PU is an aliphatic acrylic polyurethane, the type chosen for weathering, because it holds colour and gloss in UV. Use it on exposed steel, transport, and equipment that must look good for years. Its datasheet calls for a 2K polyurethane or epoxy primer, not an alkyd primer. Thin only if needed, with 2K PU thinner.
Epoxy: when chemicals and abrasion are the threat
Epoxy builds thick (70–125 µm per coat) and resists acids, alkalis and abrasion, so it suits plant rooms, chemical areas and heavy-duty primer systems. Epoxies tend to chalk and fade in direct sunlight, so outdoors they are usually topcoated with a polyurethane. That is why the 2K PU datasheet lists an epoxy primer as a recommended undercoat.
A simple rule of thumb
- Indoor or general steel, fast turnaround: primer + quick-dry enamel
- Outdoor steel that must keep its colour: 2K primer + 2K polyurethane
- Chemical splash or abrasion: epoxy primer (high build) + 2K polyurethane topcoat
- Exterior steel without two-pack equipment: AGRIP30+ high build, a single-pack primer and finish in one
Two-pack products have a limited pot life once mixed, and they are moisture-sensitive, so mix only what you can apply. See how to paint structural steel for complete systems, or ask us to specify one.