Here's how to use liquid polyurethane, adapting the application method based on the surface type for optimal results.
Using liquid polyurethane involves selecting the right application technique for the specific surface you are finishing. The method you choose helps ensure an even coat, prevents drips, and allows you to reach all areas effectively.
Choosing Your Application Method
The best way to apply liquid polyurethane depends largely on the shape and accessibility of the surface you are working on. Consider these common techniques:
- Brushing: Ideal for flat, accessible areas.
- Wiping: Best for complex, uneven, or contoured shapes.
- Spraying: Excellent for intricate details or spots that are hard to reach.
Let's look at each method in more detail.
Application Techniques
Brushing Polyurethane
For flat surfaces and covering large areas, a brush is a standard tool. To use a brush effectively:
- Dip the brush into the polyurethane, coating about an inch (2.5 cm) of the bristles. This prevents overloading the brush, which can lead to drips and runs.
- Apply the polyurethane with long, even strokes, moving with the grain of the wood or surface. This helps the finish lay flat and blend seamlessly, reducing visible brush marks.
Wiping Polyurethane
When dealing with contoured or uneven surfaces, wiping is often preferred over brushing.
- Using a rag allows you to follow the curves and shapes of the object more easily.
- Wiping helps avoid drips that are common when brushing on vertical or irregularly shaped surfaces. This technique often results in thinner coats, which may require multiple applications for desired build.
Spraying Polyurethane
For hard-to-reach areas or intricate designs where brushes and rags can't easily maneuver, spraying is the solution.
- An aerosol can of polyurethane provides a fine mist that can get into crevices and coat complex shapes evenly.
- Spraying is also useful for achieving a very smooth finish on detailed pieces, though it's important to spray in a well-ventilated area.
Summary Table of Methods
Here's a quick overview of when to use each technique:
| Application Method | Best For | Key Benefit | Note from Reference |
|---|---|---|---|
| Brushing | Flat surfaces, large areas | Even coverage, covers large areas | Use long, even strokes with the grain; dip brush ~1". |
| Wiping | Contoured, uneven surfaces | Avoids drips on tricky shapes | Use a rag. |
| Spraying | Hard-to-reach areas | Accesses difficult spots, fine finish | Use an aerosol can. |
By selecting the appropriate method for your specific project and surface, you can achieve a professional-looking and durable finish with liquid polyurethane. Always ensure the surface is clean and prepared before applying any finish.
