PPG SigmaDur 520 Alu – High-Build Semi-Gloss Polyurethane Finish

PPG SigmaDur 520 Alu is a two-component, high-build aliphatic acrylic polyurethane finish designed for long-term durability in industrial and marine environments. Offering excellent resistance to atmospheric exposure, it can be recoated an unlimited number of times, even after prolonged weathering, making it highly suitable for maintenance programs.

This tough, abrasion-resistant coating provides non-yellowing, non-chalking colour stability and cures at temperatures down to –5°C (23°F), ensuring year-round application. Available in thousands of colours, including RAL, BS, NCS, and the new NCS 2050 range, SigmaDur 520 delivers performance without compromising aesthetics. (Note: The aluminium version weathers to a grey finish.)

Easy to apply by roller or airless spray, it provides strong resistance to mineral and vegetable oils, paraffins, aliphatic hydrocarbons, and mild chemicals.

Key Features:

• Two-component, high-build aliphatic acrylic polyurethane finish

• Unlimited recoatability, even after long weathering

• Excellent resistance to UV, abrasion & atmospheric exposure

• Non-chalking, non-yellowing colour stability

• Cures down to –5°C (23°F)

• Resistant to splash of oils, paraffins & mild chemicals

• Easy application by roller or airless spray
  

Surface Preparation

Substrate conditions
• Previous coat (epoxy or polyurethane) must be dry and free from any contamination
• Surface of previous coat should be sufficiently roughened if necessary
Substrate temperature and application conditions
• Substrate temperature during application and curing down to -5°C (23°F) is acceptable; provided the substrate is
free from ice and dry
• Substrate temperature during application and curing should be at least 3°C (5°F) above dew point
• Relative humidity during application and curing should not exceed 85%
• Premature exposure to early condensation and rain may cause color and gloss change

Technical Data

Pot life
5 hours at 20°C (68°F)
Note:
- See ADDITIONAL DATA – Pot life

Spreading rate and film thickness – White
DFT Theoretical spreading rate
50 µm (2.0 mils) 11.6 m²/ (465 ft²/US gal)
75 µm (3.0 mils) 7.7 m²/ (310 ft²/US gal)

Directions for Use

Mixing ratio by volume: base to hardener 88:12 (7.33:1)
• The temperature of the mixed base and hardener should be above 10°C (50°F), otherwise extra thinner may be
required to obtain application viscosity
• Adding too much thinner results in reduced sag resistance
• Thinner should be added after mixing the components
• Aluminum version has lower gloss than the standard version and the color could be different by application method

Air spray
Recommended thinner
THINNER 21-06
Volume of thinner
5 - 10%, depending on required thickness and application conditions
Nozzle orifice
1.0 - 1.5 mm (approx. 0.040 - 0.060 in)
Nozzle pressure
0.3 - 0.4 MPa (approx. 3 - 4 bar; 44 - 58 p.s.i.)
Airless spray
Recommended thinner
THINNER 21-06
Volume of thinner
0 - 5%, depending on required thickness and application conditions
Nozzle orifice
Approx. 0.46 mm (0.018 in)
Nozzle pressure
15.0 MPa (approx. 150 bar; 2176 p.s.i.)
Brush/roller
Recommended thinner
THINNER 21-06
Volume of thinner
0 – 5%
Cleaning solvent
• THINNER 90-53

Data Sheets

SigmaDur 520 TDS

SigmaDur 520 Base MSDS

SigmaDur 520 Hardener MSDS