How to Achieve Smooth Results When Painting Wood

1. Cover Your Work Surface

   Drape plastic sheeting over the floor or other work surface to protect it from paint spills. Lay a canvas drop cloth or contractor's paper over the plastic sheeting. The plastic keeps the paint from soaking through to the floor, while the canvas provides a non-slip surface and helps to contain paint spills.

2. Clean the Wood Surfaces

   Put on eye protection and rubber gloves. Mix a solution of TSP with warm water to the proportions recommended by the manufacturer. Dip a cloth in the water, firmly squeeze it dry, then wipe down the wood to remove all oils, dirt, and grime. Rinse the surface with clean, warm water and a clean cloth. Let the wood dry completely.

   After the wood is dry, check the piece for large nicks, gouges, and scratches. If necessary, fill them with a wood filler using a flexible putty knife.

   About TSP

   TSP is a strong cleaner, degreaser, and deglosser that has long been used for cleaning surfaces in preparation for painting. If you would like to avoid using phosphates (which are banned in many communities), use a TSP substitute instead.

3. Sand the Flat Areas

   Put on a dust mask or respirator, as well as hearing protection. Sand the flat, smooth areas of wood with a random orbital sander and 180-grit sandpaper. The intent is not to strip the wood of all of the coatings and stains but simply to smooth out the surface and provide some "tooth," or slight scratches, to help the paint bond.

4. Sand the Corners and Details

   If you are sanding furniture that has uneven surfaces, switch to hand-sanding so that the sandpaper can better conform to the shape of the piece.

5. Clean Off the Dust

   Thoroughly remove the sanding dust from all surfaces. Begin with a shop vacuum outfitted with a brush attachment. Do not use a blower, as this will only redistribute the dust back on the surface. Make sure that the shop vacuum is fitted with a bag and a filter to minimize airborne dust.

   After you have removed a majority of the dust with the shop vacuum, use a tack cloth or a cotton rag that has been dipped in water and thoroughly squeezed out to remove the remainder of the dust.

6. Prime the Wood

   Mix the primer well and apply it with a brush or roller. After drying, if the primer looks transparent or streaky on the wood, prime a second time.

7. Apply Primer With a Roller (optional)

   For flat surfaces, switch to the roller to speed up the process and provide a smoother finish.

8. Sand the Primer

   Let the primer dry completely, then sand it down before painting. Use very fine 220-grit sandpaper, and apply light pressure to prevent gouging the primer. Remove the primer dust with a quick brush from the shop vacuum, followed by a light swipe of the tack cloth.

9. Paint the Wood With a Brush or Roller

   For highly irregular surfaces, such as furniture, crown molding, and trim, it is best to use a paintbrush only. For surfaces that have large, flat areas, incorporating a high-density foam roller will help you get the job done more quickly.

   Dab the end of the paintbrush bristles only about 1/3 the length of the brush into the paint each time you load the brush. Transfer the paint to the wood, dragging the brush in short strokes that run parallel to the wood grain. Keep a wet edge at all times to prevent lap marks. Do not add a second coat of paint during this step, as this can cause the paint to tear.

   For painting with the roller, insert the paint tray liner in the paint tray, then fill the tray less than halfway. Gently dab the roller into the paint. Roll the paint up and down the slope of the tray a few times to distribute the paint on the roller pad.

   Transfer the roller to the wood. Roll the paint onto the wood, beginning with light pressure only. High-density foam roller covers work better with thinner latex paint than with oil-based paints.

   For a more professional finish, looking into spraying the object rather than using a brush.

10. Sand the First Coat

    You can usually achieve an even smoother coat if you opt to sand and paint one final time. Sanding the first paint coat brings down bumps and inconsistencies introduced by the roller or brush. Using 220-grit sandpaper, sand gently by hand, or attach the paper to the orbital sander and run it extremely lightly across the surface. Do not apply pressure to the sander other than the weight of the sander itself. 

    After sanding, open up the tack cloth, bunch it up but keep it loose, then lightly run it across the surface. Too much pressure on the tack cloth will be counter-productive, as this will press the tack cloth's embedded wax onto the surface.

11. Apply a Second Coat of Paint

    Apply a final coat of paint, using a brush and/or roller, as desired. Let the paint dry as directed. If possible, let the piece dry overnight or longer before using it. Paint becomes more durable after it fully cures.

Tips for Painting Wood

High-quality results are easy to achieve if you follow a few professional tips:

• Use a brush and a roller: Paintbrushes and rollers have complementary roles. Rollers cover large areas quickly but cannot reach into corners. For smooth surfaces, use a high-density foam roller. Paintbrushes are good at painting corners and edges, but they take a long time when painting large areas. Brushing after rolling to eliminate lines and drips is a professional technique known as back-brushing.
• Primers are important: Primers are formulated to bond to problem surfaces and to give the paint a consistent surface for a smoother finish. Primer also helps prevent flashing, a condition where areas of the final paint job look as if they were painted with different paint glosses. Use a high-quality primer brand, such as Kilz or Zinsser.
• Consider paint additives: Paint can get tacky and create brush-drag if you take too long while painting. You can either pick up the pace or buy an additive that extends your working time. Penetrol and Floetrol are popular additives that help you create smooth brush strokes. Avoid painting underneath a fan or heating vent or in direct sunlight, as all of these will accelerate drying time and lead to tacky paint.