Sanding between top coats is a crucial step to ensure a smooth, level, and well-adhered finish. The process involves using fine grits and a light touch primarily for smoothing, not flattening the surface.
Sanding serves two main purposes in the finishing process:
- Smoothing: It knocks down any raised grain, dust nibs, or imperfections from the previous coat, leaving a smooth surface for the next layer.
- Adhesion: It creates a fine "tooth" or microscopic scratches that allow the subsequent coat to bond better to the surface.
The Method: Smoothing with Fine Grit
At this stage, the goal is primarily smoothing the previous coat. According to one method, there is no need to use a sanding block as you are not flattening the surface. Instead, a flexible approach works well for contours and tight spots.
A highly effective technique involves creating a simple sanding pad:
- Material: Use P320-grit stearated paper. Stearated paper resists clogging, which is common when sanding finishes.
- Preparation: Make a pad by folding a quarter sheet of this paper into thirds.
- Application: This folded pad works best for sanding by hand, allowing you to easily get into corners and other tight areas.
Key Principles:
- Grit Size: Use fine grits, typically P320 or finer, depending on the finish and desired smoothness.
- Touch: Apply a light touch. Excessive pressure can cut through the finish, requiring repairs.
- Coverage: Sand the entire surface evenly, focusing on removing any imperfections.
- Cleaning: After sanding, thoroughly remove all dust before applying the next coat. A vacuum followed by a tack cloth is recommended.
Materials
| Material | Description | Purpose |
|---|---|---|
| P320-grit stearated paper | Fine grit sandpaper with coating | Smoothing finish, resisting cloggin |
| Quarter sheet | Standard sandpaper size | Convenient size for folding into a pad |
Using a folded pad of P320-grit stearated paper with a light touch is an effective way to smooth the surface and prepare it for the next coat, especially in areas where a block is cumbersome.
