Coastal and marine condensers
Rooftop and outdoor units near the sea, where uncoated fins pit quickly.
Heat exchanger material
5052 Colour-Coated Aluminium Foil for Fin Stock
5052 colour-coated fin foil is 5052-O aluminium foil, typically about 0.2 mm thick, lacquered on both sides with a polyester coating and slit to fin widths. It is chosen over standard 8011 or 1100 fin stock when fins need more strength and corrosion resistance, for example in coastal condensers, industrial coolers and power-electronics heat sinks. Metline supplies coated 5052 fin foil to EN 683 to heat exchanger makers worldwide.
- Alloy
- EN AW-5052 (AlMg2.5), O temper
- Thickness
- about 0.15 – 0.3 mm
- Coating
- Polyester, two layers per side
- Standard
- EN 683-1/-2/-3
Why use 5052 for fin stock?
Most air-conditioner fins are made from 8011, 8006, 3102 or 1100 foil, which conduct heat very well and form easily. In harsh environments, though, thin fins corrode quickly, and thin soft fins bend under cleaning, hail or vibration. 5052 trades some thermal conductivity for much higher strength and better resistance to pitting in salt and industrial air.
Pure and low-alloy fin alloys conduct about 200 – 230 W/m·K; 5052 conducts about 138 W/m·K. For a thin fin, efficiency depends on conductivity, thickness and fin height, so the loss is real but modest for short fins, and is often accepted for the gain in durability. Adding a polyester coating on both sides further isolates the aluminium from moisture and salt, and coloured coatings, usually black, raise surface emissivity, which helps radiative cooling in natural-convection heat sinks.
Material and coating specification
Base foil
- Alloy
- EN AW-5052 (AlMg2.5) to EN 573-3
- Temper
- O (annealed) for fin forming
- Delivery conditions
- EN 683-1 (fin stock technical delivery)
- Mechanical properties
- EN 683-2
- Tolerances
- EN 683-3
- Certificate
- EN 10204 3.1
| Coating parameter | Typical value (each side) |
|---|---|
| Resin system | Polyester (epoxy or other systems on request) |
| Colour | Black or to order |
| Layers | Primer plus top coat |
| Surface character | Hydrophobic (water beads and runs off) |
| Coating mass | about 11 – 15 g/m² |
| Dry film thickness | about 10 – 14 µm |
Hydrophobic coatings shed water as droplets and are preferred where fins run dry or where coating durability matters most. For evaporator coils that run wet, a hydrophilic lacquered foil that spreads condensate into a thin film reduces air-side pressure drop and water carry-over.
Mechanical properties and tolerances
| Property | Typical requirement |
|---|---|
| Tensile strength | 175 – 225 MPa |
| Yield strength (0.2 %) | over 65 MPa |
| Elongation | over 20 % |
| Erichsen cupping (no lubricant) | over 6.5 mm |
| Thickness tolerance at 0.2 mm | ±0.02 mm at any point |
| Width tolerance (slit) | ±0.3 mm |
Values from typical customer specifications; properties not stated follow EN 683-2, dimensions EN 683-3.
Common slit widths are matched to the fin press, for example around 345, 427 and 455 mm. The high Erichsen value matters because fin collars are drawn and flared around the tube holes; a brittle coating or hard foil would crack at the collar.
Coating inspection and test methods
| Test | Typical requirement | Method |
|---|---|---|
| Adhesion | No delamination after Erichsen cupping plus tape pull | EN 13523 |
| Cure (solvent resistance) | More than 20 MEK double rubs | EN 13523 |
| Salt-spray corrosion | Specified hours in 5 % NaCl at 35 °C without attack, protected edges | ASTM B117 |
| UV resistance | Gloss retention after UVA-340 cycling | EN 13523-10 |
| Coating thickness and mass | Within agreed range | EN 13523 / gravimetric |
Where coated 5052 fin foil is used
Industrial coolers
Air coolers and dry coolers in chemical, wastewater and food plants with corrosive atmospheres.
Power-electronics heat sinks
Inverters, converters and LED fixtures, where black coatings aid radiative cooling.
Transport cooling
Engine, oil and charge-air coolers needing robust fins.
Refrigeration
Condensers and evaporators in humid, salt-laden or ammonia environments.
Visible coils
Appliances and architectural units where a dark, uniform fin colour is preferred.
Coil dimensions and packing
Typical coil and pallet data
- Core inner diameter
- 150 mm (others on request)
- Coil outer diameter
- up to about 1000 mm
- Coil weight
- up to about 840 kg
- Pallet
- Euro pallet 1200 × 800 mm, eye-to-wall, package height up to about 1200 mm
- Protection
- Cardboard interlayers, edge protection, PE stretch wrap; no polystyrene
- Traceability
- One annealing and coating batch per pallet, labelled
References and standards
- EN 683-1/-2/-3 – Aluminium and aluminium alloys: finstock
- EN 573-3 – Chemical composition and form of wrought products
- EN 13523 – Coil coated metals: test methods
- ASTM B117 – Standard practice for operating salt spray (fog) apparatus
5052 coated fin foil: FAQs
Why choose 5052 instead of 8011 for fins?
5052 is stronger and more resistant to pitting in salt and industrial air, so fins last longer and resist bending. The trade-off is lower thermal conductivity, about 138 against roughly 220 W/m·K.
Is the coating hydrophobic or hydrophilic?
The standard polyester coating is hydrophobic. Hydrophilic coatings are better for wet evaporator coils; tell us the duty and we will recommend the coating.
What does the black coating do?
It protects the aluminium from moisture and salt and raises surface emissivity, improving radiative heat transfer in natural-convection heat sinks.
Can coated fins be formed with collars?
Yes. O-temper 5052 with Erichsen above 6.5 mm and a flexible polyester coating forms collars without cracking when press tooling is set correctly.
What thickness is typical?
About 0.15 – 0.3 mm, with 0.2 mm common. Thickness tolerance is typically ±0.02 mm at any point.
Need coated 5052 fin foil?
Send thickness, width, coating and coil requirements. We reply with availability, test data and a delivered quote.
