Polyurethane paint: Everything you need to know

Polyurethane paint is prized for its durability and resistance, whether in industrial or domestic applications. Its polyurethane resin-based formulation gives it a smooth finish that is resistant to scratches, chemicals and weathering. This type of paint is particularly popular for protecting highly stressed surfaces, such as car bodies, boats or industrial floors. In this article, find out how it works, its advantages and disadvantages, and how to apply it.

What is polyurethane paint?

Polyurethane paint is a polyurethane resin-based paint which, once dry, forms a highly resistant and durable film. It offers excellent adhesion to a wide range of substrates including metal, wood, concrete and even plastic, making it versatile for both indoor and outdoor use. Once cured, polyurethane paint offers remarkable resistance to impact, abrasion, UV and chemicals, as well as a smooth, glossy finish.

How does polyurethane paint work?

Polyurethane paint dries through a polymerisation process that makes the paint film extremely hard and resistant. It is available in two versions: single-component, ready-to-use, and two-component, which requires the mixing of a base and a hardener to activate polymerisation. This chemical process is crucial to the paint’s durability and performance. Unlike other paints, polyurethane can withstand harsh environments while retaining its gloss and strength.

Types of polyurethane paint

1. Single-component polyurethane paint: Easier to use, this version is ready-to-use and requires no mixing. It’s ideal for domestic projects such as furniture, floors and woodwork.
2. Two-component polyurethane paint: More complex but also more effective, this paint offers greater resistance to impact, UV rays and chemicals, making it the preferred choice for industrial and marine applications.

Polyurethane paint applications

Polyurethane paint is used in a variety of fields, including :

• Cars and aircraft: For bodywork and parts requiring extra protection against the elements and impact.
• Boats: Its water and UV resistance makes it an excellent coating for boat hulls.
• Industry: Used for factory and warehouse floors where extreme conditions and heavy traffic are present.
• Furniture and woodwork: Polyurethane paint protects wood while providing a long-lasting aesthetic appearance.

Advantages of polyurethane paint

• Extreme durability: Its resistance to abrasion, chemicals and weathering makes it ideal for exposed surfaces.
• Smooth, attractive finish: Provides a long-lasting gloss that enhances surfaces.
• Versatility: Can be applied to many types of surface (metal, wood, concrete).
• Easy to clean: Surfaces painted with this paint are easy to maintain.

Disadvantages of polyurethane paint

• Complexity of application: The two-component version requires precise mixing and skilled application techniques.
• Drying time: Although fast in the single-component version, the two-component version requires a longer drying time.
• Price: Generally more expensive than other types of paint, mainly because of its advanced technical properties.

Tips for applying polyurethane paint

• Prepare the surface: Clean thoroughly and sand if necessary to ensure good adhesion.
• Use the right tools: Use a spray gun for even application.
• Apply thin coats: Several thin coats are better than one thick coat to avoid drips.
• Respect drying times: Don’t rush the process, especially with the two-component version, for optimum results.

Example of the application of polyurethane paint by Mellowpine Woodworking

Applying polyurethane paint with an airless sprayer

Applying polyurethane paint with an airless spray gun is an effective way of achieving an even, professional finish. Here are some key steps for a successful application:

1. Preparing the equipment: Use a spray gun suitable for thicker products such as polyurethane paint. An airless spray gun with a nozzle between 0.013 and 0.017 inches is recommended (of course, please check the manufacturers’ technical data sheets, as this can vary between different polyurethane paints).
   1. Example of a machine for polyurethane painting on small and medium surfaces: Wagner SF 23 CR (mechanics perfectly adapted; example with a modified discharge valve)
   2. Example of a machine for polyurethane painting on large surfaces: Wagner SF 33 Plus
2. Dilution: Depending on the product, a slight dilution (5-10%) may be necessary to avoid clogging.
3. Pressure and settings: Adjust the gun pressure to between 120 and 160 bar for an even application. Test on a small area first to adjust the spray pattern.
4. Distance and movement: Hold the gun approximately 25-30 cm from the surface and apply the paint with regular, parallel movements. Work in criss-cross strokes for even coverage.
5. Maintaining the equipment: Clean the spray gun thoroughly after each use to prevent the paint from drying and clogging the nozzle and airless equipment.

Wagner SF 33 Plus – 2388259 in shop

The airless spray gun reduces product waste and speeds up work, while providing an exceptional quality finish.

Polyurethane paint is a high-performance choice for all your projects requiring increased resistance and a quality finish.