Team Spindle Sander: Why You Need One

The finish on a woodworking project is what people see and touch first. A beautiful piece of furniture with a poor finish looks cheap, while a simple design with a flawless finish looks expensive. Understanding finishing is as important as understanding joinery.

Choosing the Right Finish

Every finish involves trade-offs between appearance, durability, ease of application, and repairability. No single finish excels at everything, so matching the finish to the project's requirements is the first and most important decision.

Film-Forming Finishes

Film-forming finishes sit on the wood surface and create a protective layer. Polyurethane, lacquer, and varnish fall into this category. They offer excellent protection against moisture and wear but can be difficult to repair if damaged. The plastic-like surface is durable but can change the wood's natural feel.

• Oil-based polyurethane — Extremely durable, amber tone, slow drying. Best for high-traffic surfaces.
• Water-based polyurethane — Clear finish, fast drying, low odor. Good for lighter wood species where amber tone is undesirable.
• Lacquer — Fast drying, easy to repair, builds quickly. Professional favorite but requires spray equipment and ventilation.
• Shellac — Natural, food-safe (when pure), easy to apply and repair. Moderate durability, not resistant to alcohol or water rings.

Penetrating Finishes

Penetrating finishes soak into the wood rather than sitting on top. Oils and oil-wax blends fall into this category. They preserve the natural feel of wood and are easy to apply and repair. However, they offer less protection than film-forming finishes and require periodic reapplication.

Surface Preparation

The finish cannot hide what is underneath it. In fact, applying finish magnifies surface imperfections by creating contrast between finished and unfinished areas. Every scratch, mill mark, and glue spot becomes visible under a coat of stain or clear finish.

Sanding Sequence

Start with a grit coarse enough to remove any defects quickly, typically 120 grit for most hardwoods. Progress through 150, 180, and 220 grit, spending equal time at each grit. Skipping grits does not save time because each grit must remove the scratches left by the previous one.

Raising the Grain

After sanding to 220 grit, dampen the surface with a wet cloth and let it dry completely. This raises any compressed wood fibers that would otherwise spring up when they encounter water-based stain or finish. Sand lightly with 220 grit after the surface dries to remove the raised fibers. This step produces a noticeably smoother final finish.

Application Techniques

Brushing

Use a high-quality natural bristle brush for oil-based finishes and a synthetic bristle brush for water-based finishes. Apply thin, even coats and maintain a wet edge to prevent lap marks. Brush with the grain, not against it.

Wiping

Wiping finishes on with a cloth gives you the most control over thickness and evenness. Fold a lint-free cloth into a pad, apply finish to the pad, and wipe in long strokes with the grain. This technique works well for oils, wiping varnish, and diluted polyurethane.

Troubleshooting Common Finish Problems

• Bubbles — Caused by shaking the can or brushing too aggressively. Stir, do not shake, and apply with minimal brush strokes.
• Dust nibs — Work in the cleanest environment possible. Wet the floor to settle dust. Apply finish after other shop work is done for the day.
• Blotchy stain — Pre-seal with a wood conditioner or thin coat of shellac before applying stain. Test on scrap first.
• Orange peel texture — Usually caused by spraying finish that is too thick or at too great a distance. Thin the finish and spray closer with lighter coats.

A great finish takes patience and practice. Experiment on scrap before committing to your project, keep your workspace clean, and remember that thin coats applied properly always outperform thick coats applied hastily.