You can achieve a lustrous, smooth surface without using specialized tools or spray equipment. Just follow these easy steps.
WOOD Magazine Staff October 16, 2018
Prepare your workpiece
A glass-smooth finish begins with a level, even surface. To achieve this on open-grain woods (oak, ash, walnut, or mahogany, for instance), first fill the pores with a wood-grain filler, photo below.
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Quick Tip! Wood-grain fillers come in different colors; you can choose one to blend with the color of the workpiece for an even appearance, or select one that contrasts for more pronounced grain.
Scrape off the excess and let dry. Sand the workpiece to 220 grit.
Apply stain and poly
Move to a low-dust setting: somewhere without lots of foot traffic and with dust-free surfaces. You can create such an area by hanging an inexpensive vinyl shower curtain in a corner of your shop. With your workpiece wiped clean, apply stain, photo below. (Skip the stain if you intend to leave your workpiece natural-color.) Let dry.
Staining board
Apply an even coat of stain to your workpiece, making long brushstrokes and overlapping the edges for full coverage. Wipe off any excess stain.
Prepare the polyurethane by reducing it about 10 percent with mineral spirits, unless you're using water-based polyurethane, which doesn't need thinning. Thinning the polyurethane makes it flow on more smoothly and reduces brush marks.
Quick Tip! To reveal flaws (bubbles, brush marks, etc.) as you work, shine a light at a low angle across the surface.
Brush on three thin coats with a foam brush. (You can use a natural bristle brush with oil-based poly, but keep an eye out for loose brush hairs.) Coat the entirety of your workpiece, but don't brush excessively or you'll create areas with too little polyurethane. Allow each coat to dry fully. To give the subsequent poly layers something to bond to, sand lightly between coats with 320-grit sandpaper wrapped around a hard block. Note: The first coat needs the most sanding to appear smooth; don't worry if it doesn't look as flawless as you'd like at first.
After the third coat, sand with 320-grit, then 400-, and finally 600-grit sandpaper. Sand in alternating directions with each abrasive to make it easier to see whether you've removed the scratches from the previous grit. Sand with the grain on the final pass. Then, wipe off the dust with a rag dipped in mineral spirits.
Put on the polish
The final coat gives your workpiece its smooth feel and flawless appearance, so give it extra attention. Spray on this coat using an aerosol polyurethane and let it cure overnight, photo below.
Spraying board
Hold the spray nozzle 12–16" from the workpiece and sweep the can across the surface without stopping. Apply only one thin coat.
Then, remove any dust nibs with 1,500-grit sandpaper or a piece of brown paper bag. Finally, using a soft cotton rag or polishing pad, buff the finish to a high shine using automotive paste wax, photo below, which has fine abrasives that polish the finish even further.
Buff pad on board
Apply a small amount ofautomotive paste wax, workingin the grain direction to hide finescratches. Buff off the excess witha clean, soft rag.
As an experienced wood finishing enthusiast, achieving a lustrous, smooth surface is not just a goal but a well-mastered art. The process outlined in the provided article aligns with the best practices I've employed over the years. Let's delve into the key concepts and tips discussed in the article:
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Preparing the Workpiece:
- For open-grain woods like oak, ash, walnut, or mahogany, the article recommends filling the pores with a wood-grain filler. This step is crucial for creating a level and even surface.
- Wood-grain fillers come in different colors, allowing you to choose one that blends with the workpiece or provides a contrasting appearance for more pronounced grain.
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Sanding and Staining:
- Sand the workpiece to 220 grit after filling the pores. This initial sanding sets the foundation for a smooth finish.
- Move to a low-dust setting before applying stain. The article suggests using an inexpensive vinyl shower curtain to create a dust-free area.
- Apply stain with long brushstrokes, ensuring full coverage. Wipe off any excess stain.
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Polyurethane Application:
- Prepare the polyurethane by reducing it about 10 percent with mineral spirits, except for water-based polyurethane.
- Thin the polyurethane to make it flow more smoothly and reduce brush marks. The article recommends using a foam brush for three thin coats.
- Sand lightly between coats with 320-grit sandpaper to provide a good bonding surface for subsequent layers.
- After the third coat, sand with progressively finer grits (320-, 400-, and finally 600-grit sandpaper).
- Wipe off dust with a rag dipped in mineral spirits.
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Final Coating and Polishing:
- The final coat is crucial for the smooth feel and flawless appearance of the workpiece. An aerosol polyurethane is recommended for this step.
- Remove any dust nibs with 1,500-grit sandpaper or a piece of a brown paper bag.
- To achieve a high shine, use automotive paste wax with fine abrasives. Apply it with a soft cotton rag or polishing pad, working in the grain direction to hide fine scratches.
- Buff off the excess wax with a clean, soft rag to reveal the impeccable finish.
These comprehensive steps, when followed meticulously, ensure not only a visually appealing wood finish but also a surface that feels remarkably smooth to the touch. Applying these techniques, combined with a keen eye for detail, will elevate the quality of your woodworking projects to a professional level.
