Polyurethane Primer (Iron Red, Grey) - Technical Guide for Acrylic

Overview

Acrylic coatings are the premium choice when colour, gloss and long-term appearance matter. The chemistry — an acrylic resin crosslinked with an isocyanate or melamine — gives exceptional UV stability and gloss retention with no chalking or yellowing over a service life measured in decades.

The range at Delshine spans three distinct tiers. Acrylic primers and finishes are the workhorses. Acrylic polyurethane topcoats add the toughness and chemical resistance of a polyurethane film. Fluorocarbon finishes — the PVDF-based system — are the ultimate in colour and gloss retention, used on landmark buildings and infrastructure where a coating must still look new after 25 years.

Acrylic and fluorocarbon systems are the natural choice for steel structures, bridges, ships, and any exterior where the appearance is part of the specification and not just the protection.

Product identification

The identifiers below are the ones printed on the drum and quoted on the purchase order. Always order and dispatch by code, because the grade and the zinc or temperature variant cannot be inferred from the trade name alone.

Where this product is used

• Exterior architectural steel and landmark building facades
• Bridge handrails, balustrades and structural steelwork
• Marine topsides and superstructure coating
• Road marking paint on highways and urban roads
• Overhead steel structures and cranes
• Fluorocarbon facades on high-rise and commercial buildings
• Roofing and canopy steelwork
• Decorative metalwork, railings and architectural features

How it works in the coating system

A primer is the first layer in the coating system, and it decides how well everything that follows will adhere. Its job is to wet out the prepared substrate, key into its surface, and hold the coating together as one film.

Applied thin, a primer wets and anchors. Applied too thick, it becomes brittle, stresses the substrate and can peel as a sheet. The right dry film thickness for a primer is the one that covers the surface completely without building a film that can crack.

Purpose in the system: Applied directly to the prepared substrate, before any intermediate coat or topcoat.

Technical properties

The values below are the typical published range for this product family. The exact figures for your batch are confirmed on the batch certificate and the current technical data sheet.

Surface preparation

1. Abrasive blast steel to Sa 2½ (ISO 8501-1). For architectural work and fluorocarbon systems, blast to Sa 3 and check the surface profile against the coating manufacturer's requirement, typically 40-70 µm.
2. Ensure all surfaces are free of mill scale, rust, weld spatter, oil and grease. Weld spatter must be removed and the area abraded.
3. Round all edges to a minimum 2 mm radius. This is a visible quality item on architectural work as well as a durability one.
4. For stainless steel or aluminium, use a dedicated wash primer or non-ferrous etch primer — do not use a steel system.
5. Control conditions during application: substrate at least 3 °C above dew point, ambient above 10 °C, humidity below 80%.
6. Mask and plug before coating, and remove masking tape while the coating is still slightly tacky for a clean edge.

Application procedure

Apply by brush, roller, conventional air spray or airless spray depending on the product. Primers are usually thin enough to spray well and wet out a blasted surface completely.

Work at a consistent wet film thickness and avoid over-application at edges, welds and connections — sags and runs at these details are the most common primer defect.

Allow the primer to reach the specified state before overcoating. On some systems a primer should be topcoated while it is still slightly tacky for best intercoat adhesion; on others a full cure with an abrasion between coats is required.

Mixing, ratio and induction time

Two-pack primers are mixed in the ratio stated on the data sheet, typically 4:1 or 5:1 by volume for epoxy primers and 3:1 for polyaspartic systems. Allow the full induction time before thinning and application, and observe the pot life strictly — a primer that has begun to gel will not perform.

Cure, recoat window and service readiness

Recoat windows depend on temperature, humidity and film thickness, but a typical epoxy primer is recoatable after 12 to 24 hours at 20-25 °C and needs 7 days for full cure. Polyaspartic primers cure far faster and may be recoatable within 2 to 4 hours. Exceeding the maximum recoat interval requires the surface to be abraded and re-cleaned before the next coat.

Coverage and thickness calculation

Typical dry film thickness is 40-80 µm for a conventional primer and 60-100 µm for a high-build anticorrosive primer. At 60 µm, one litre covers roughly 12-14 m². Always measure the wet film and calculate back from the solids content to confirm the specified DFT is being achieved.

Technical note. Coverage (m²/litre) = (volume solids × 10) / DFT (µm)

Worked example

Advantages

• Outstanding UV and weathering resistance with minimal chalking, fading or yellowing.
• Excellent gloss retention and colour stability over long service periods.
• Fast cure and good throughput — acrylic coatings can often be overcoated within a few hours.
• Good adhesion and flexibility, with excellent edge retention.
• Fluorocarbon finishes provide the best-in-class colour and gloss retention available in the market.
• Wide colour range, including RAL, BS and custom-matched shades for architectural projects.

Limitations and precautions

• Aromatic acrylic finishes will discolour; aliphatic grades are required for UV-exposed service.
• Coverage is relatively thin compared with high-build epoxy — these systems rely on film build from multiple thin coats.
• Fluorocarbon systems are expensive and the coating must be applied by a trained applicator to perform as designed.
• Not suited to immersion in aggressive chemicals without a specific grade.
• Acrylic coatings cure poorly in cold or humid conditions and will blush if applied outside the recommended window.

Storage and shelf life

• Store in original sealed containers in a cool, dry, ventilated store between 5 °C and 30 °C.
• Keep the hardener component away from moisture — it reacts with atmospheric water.
• Protect from direct sunlight and do not store above 40 °C.
• Rotate stock first-in-first-out and observe the labelled shelf life, typically 12 months unopened.

Safety, PPE and ventilation

• Wear chemical-resistant gloves, goggles and suitable protective clothing.
• Use an organic-vapour cartridge respirator when spraying, and supply ventilation for the coating area.
• Keep away from heat and ignition sources; solvents are flammable.
• Do not spray in windy conditions outdoors without appropriate containment and respiratory protection.
• Collect solvent waste and dispose of it through a licensed contractor.

Quality control and inspection

• Check the surface preparation standard and the blast profile before coating begins — this is recorded on the inspection report.
• Verify film thickness by wet film gauge during application and by magnetic induction gauge or dry film readings on the completed coat.
• Holiday test the primer before overcoating, particularly over welds, connections and edges.

Pricing and how to order

Delshine quotes this product per square metre at a specified dry film thickness, or per drum/litre depending on the project. The material cost is usually the smallest part of the installed cost — surface preparation, access and application labour dominate. Send us the substrate, the service conditions and the required DFT and our technical team will return a full system recommendation with a firm price.

Acrylic and fluorocarbon coatings are quoted per square metre at a stated dry film thickness, with colour and sheen usually driving the price difference. Fluorocarbon is several times the price of a standard acrylic finish — a 2,000 m² facade moves from a modest figure to a significant one purely by changing the topcoat, which is why the specification stage matters so much.

Frequently asked questions

The questions below are the ones our technical team is asked most often about this product family.

Related products

These products are normally used in the same system as the product described above.

• Acrylic Primer (White, Grey)
• Acrylic Finish (All Colors)
• Acrylic Road Marking Paint
• Road Marking Paint (Yellow)

See all products