Wood Finishing Tips
Get a silky smooth finish on your next project
Hand-Sand the Curves
Sand curved surfaces—and other areas an electric sander can’t reach—by hand. Treat all areas equally, using the same progression of sandpaper grits for both hand and power sanding. Start with 80-grit to sand away blemishes, then use 120-grit and finally 180-grit. Using these exact grits isn’t vital (100-150-180 works too), but it’s important to progress in steps, removing deeper scratches and leaving finer scratches each time.
Sand Without Scratches
A random orbital sander leaves scratches that are practically invisible, so you can sand across joints where grain changes direction. But move slowly (about 1 inch per second) and apply light pressure. Otherwise, you’ll get swirly scratches.
Test Stains Thoroughly!
You can’t rely on those stain samples on display in stores. Actual color varies a lot, depending on the type of wood and how you prepared it for finishing. So save scraps from your project, run them through the same sanding process and use them to test finishes. If you didn’t build the item you’re finishing, run tests on an inconspicuous area—the underside of a table, for example. Test stain on scraps to get the color you want. Leaving excess stain on the wood for longer or shorter periods won’t affect the color much. If it’s a custom color you’re after, you can mix stains of the same brand.
Test Clear Finishes, Too
Oil-based poly has an amber tone that can dramatically change the color of stained or unstained wood. Water-based polyurethane affects the color only slightly. The same stain was used on the samples shown in this photo.
Sand With the Grain
Sand with the grain when hand sanding or using a belt sander. Scratches are hard to see when they run parallel to the grain. But even the lightest scratches across the grain are obvious, especially after staining.
Consider a Wood Conditioner
Some woods absorb stain unevenly, which causes dark blotches to appear. Birch, maple, pine and cherry can all play this ugly trick on you. It’s hard to eliminate this effect, but you can limit it by applying a wood conditioner before staining. Conditioner also prevents wood’s end grain from absorbing more stain than the face grain. Get a quart at a home center or paint store.
Renew Woodwork Without Refinishing
If your stained and varnished woodwork is looking a little shabby, you can save time and money with this quick fix. You don’t have to strip the finish from your dingy woodwork. Just head to the store and pick up wood stain that’s a close match. We like gel stain for this fix, but any wood stain will work.
Start your renewal project by washing the woodwork with soapy water. Rinse with clear water, then gently scrape off any paint spatters with a plastic putty knife. When the wood is dry, dip a rag into the stain and wipe it over the wood. Bare spots and scratches will pick up the stain. Finish by wiping the woodwork with a clean cloth to remove the excess stain. After the stain dries for a few days, you can add a coat of furniture wax or wipe-on poly to really liven up the old wood.
Better Brushes are the Key
Usually, a brush is the best tool for applying polyurethane. For water-based poly, a synthetic brush (such as nylon or polyester) is best. For oil-based poly, use a natural-bristle brush. In either case, plan to spend more for a good-quality brush. Quality brushes hold more finish, lay it on smoothly and are less likely to leave lost bristles in your clear coat. If you clean your brush immediately after use, it’ll serve you well far into the future.
Leave Mistakes Alone (Usually)
When you notice a run, missed spot or other problem in the polyurethane you applied minutes earlier, you’ll be tempted to brush it out. Don’t. The finish may look wet, but chances are it’s already sticky, and brushing will only make a mess. There are a couple of exceptions to this rule: You can pop tiny air bubbles with a pin, and you can pluck out a hair, a lost bristle or unfortunate fly using sharp tweezers and a steady hand.
Wipe Instead of Brush
Wipe oil-based polyurethane onto hard-to-brush surfaces using a soft, lint-free cloth. Wiping leaves a thinner coat than brushing, so you’ll have to apply more coats. Water-based poly becomes sticky too fast for wiping.
Use a Pad on Large Areas
Apply water-based polyurethane to large surfaces fast by using a paint pad. Water-based poly dries quickly and may not allow enough “wet” time for brushing out big areas.
Spray on the Final Coat
Here’s a trick for getting a glass-smooth finish on your next woodworking project. Start by brushing on a coat of gloss polyurethane. Let it dry overnight. Then lightly sand with 320-grit sandpaper to remove imperfections. Use a tack cloth or vacuum cleaner and soft brush attachment to remove the dust. Repeat this process for the second coat. Finish up by spraying on the final coat. You can buy aerosol cans of polyurethane in satin, semigloss and gloss finishes. Any of these can go over the gloss coats.
Brushing on the first two coats allows you to build up a thicker layer of finish with less cost and effort than spraying from cans. And using an aerosol can to apply the final coat produces a professional-looking finish, free of brush marks.
Don’t Sand Through the Stain
When sanding between coats, it’s easy to rub right through the clear coat, removing the stain below. So sand super lightly after the first coat, just enough to cut down any dust whiskers on the surface. If there are bigger problems—such as runs—deal with them after the second coat when you can sand a bit harder. To repair rubbed-through spots, just apply new stain. Immediately wipe away any stain that gets on the surrounding polyurethane.
Sand Curves With a Pad
When sanding between coats, smooth curves with a steel wool substitute such as 3M’s Scotchbrite pads. Steel wool leaves fibers behind, which can cause stains in the finish.
Sand Fine Surfaces With Wet/Dry Sandpaper
Lightly sand between coats with 400-grit wet/dry sandpaper, which won’t fall apart when it gets wet. A little water provides lubrication and keeps the finish from clogging the paper. Sanding after each coat (except the last) rubs out imperfections and roughens the surface for better adhesion of the next coat. In most cases, this is a quick job, more like wiping the surface than sanding it. When the sanding is done, wipe away the residue with a damp rag.
Three-Stage Brush-Cleaning System
Save time and mineral spirits with this three-container brush-cleaning method. Partially fill three containers with mineral spirits. When you’re done working for the day, swish your brush around in the first container. Wipe it along the edge of the container to remove as much finish as you can. Then repeat the process in the second container. By now the brush will be pretty clean.
Suspend the brush in the third container. Drill a hole in the handle and suspend it from a wire or dowel so that the bristles aren’t resting on the bottom of the container. Put a lid on the first two containers, and wrap plastic wrap or aluminum foil around the brush handle on the third container. You can use the same mineral spirits for several brush cleanings.
When the first container gets too full of old finish, dump it into a fourth container labeled “used mineral spirits.” Shift the second and third containers to positions one and two, and pour clean mineral spirits into the one you emptied and place it at the end of the line. You can reuse the mineral spirits from the “used” container after the finish settles. Decant it carefully to avoid stirring up the gunk on the bottom.
Scrape Paint Faster
Steel scrapers work great—for the first few minutes. Then they need to be sharpened or replaced. But a carbide scraper blade will stay plenty sharp for a long time, even when you’re removing thick paint buildup.
In addition to a reversible carbide blade, this heavy-duty scraper has a knob on top for two-handed operation—a must for tough scraping jobs. You can even flip the scraper over and use the knob as a hammer to set protruding siding nails. If you’ve ever scraped paint from an old house, you know how handy that is.
Work Faster With Pyramids
These handy plastic pyramids hold your project off the surface so you can paint the edges easily. Better yet, you can finish the front of doors (or the top of shelves) without waiting for the back to dry. Paint the back of the door and set it painted side down on the pyramids while you paint the front. The sharp points on the pyramids will leave only little spots on the wet paint, and they’re easy to touch up later. You’ll find plastic pyramids at home centers, paint stores and hardware stores.
If you have lap siding to paint, you can save a lot of time by painting the edges of window and door casings the same color as the siding. Most pros do it this way, and the beauty is, nobody will ever notice this little shortcut. Caulk the joint between the casing and the siding as usual. Then when you paint the siding, just extend the paint onto the edge of the casing instead of meticulously cutting in. If you get paint on the face of the casing, wipe it off with a wet rag to create a neat edge.
You can hide scratches with permanent-ink felt-tip markers. You can either use the furniture touch-up markers available at hardware stores and home centers, or, to get an exact match, buy markers at an art supply store that carries an array of colors. For thorough coverage, you may need to dab the ink onto the scratch, let it dry, then even out the color by stroking lightly across it with the tip. Keep in mind that colors tend to darken when they soak into wood fibers.
Clean Dirty, Greasy, Gummy Surfaces
The results of a simple surface cleaning with mineral spirits may amaze you. Polish buildup and the dirt embedded in it muddy the finish but will wipe away. Don’t use stronger solvents; they might dissolve the finish itself.
Soak a coarse, absorbent, clean cloth with mineral spirits and wipe the finish. Keep applying and wiping until the cloth no longer picks up dirt. Then do a final wipe with a fresh, clean rag.
Clean crevices, grooves and carved areas with cotton swabs dipped in mineral spirits.
Fill in gouges with colored putty sticks, sold at most hardware stores and home centers. This putty works well for small holes and nicks but is somewhat trickier to use as a fill for larger damage like we show here. Unlike hardening putties, it remains soft and somewhat flexible, so you have to shape it carefully. And it won’t hold up under heavy wear.
Buy several sticks of putty similar to the color of the stain you want to match. Scrape flakes from each, then mix and knead them with your fingertips until the color is right. The heat from your fingers also softens the putty for easy application. Make the patch slightly darker than the furniture; lighter will be more obvious. Press putty tightly into the gouge with a small flat stick, then flatten it and scrape away the excess with the stick’s long edge. Round the end of the stick with sandpaper.
Wipe away any putty adhering to the wood around the gouge, and smooth the surface of the putty with a clean cloth. A thin, light-colored line will usually appear around the perimeter of the patch. Use a matching marker to color this line. Spray the patch with two or three quick passes of shellac, then after it dries, a few quick passes of spray lacquer—either high gloss or satin, depending on your furniture’s finish. Never apply lacquer or polyurethane/varnish directly over a putty patch; it will leave a permanently soft mess. Shellac will harden; however, the patch will remain somewhat pliable under the finish, so don’t attempt this on a heavy-wear surface.
Wipe Away Scratches and Recoat the Surface
You can buff out fine scratches using very fine (0000) steel wool saturated with clear Danish oil. (You can also use ultra-fine automotive rubbing compound.) The process shown here only works for scratches in the finish itself, not scratches that are all the way into the stain or the wood.
Pour a generous amount of clear or neutral Danish oil onto a very fine steel wool pad. Rub the surface with the oil-saturated pad using your flat hand. Rub with the grain, never against it or at an angle to it. Continue rubbing until you remove enough of the clear surface finish to eliminate the scratches, but be careful not to remove any of the stain below the clear finish. Rub not only the scratched area but also the area around it in gradually decreasing amounts. Be careful to rub edges or corners excessively; they wear through quickly.
Wipe away all the Danish oil with rags or paper towels, then thoroughly clean the entire surface with mineral spirits several times to make sure all the oil is removed. If any oil remains, the lacquer won’t adhere. Allow the surface to dry overnight before applying lacquer.
Spray the entire surface with clear lacquer. Move the spray can in one continuous, straight stroke, allowing the spray to extend beyond the edges in all directions. Wipe the nozzle with a rag after each stroke to prevent drips. Move with the grain, and make sure the angle of the spray remains the same all the way across. Keep the spray aimed away from other surfaces that you don’t want coated, or mask them with newspaper.
CAUTION: Rags and steel wool saturated with Danish oil can spontaneously combust if left bunched up. Dry them outdoors, spread out loosely, when the oil has dried, you can safely throw the rags and steel wool in the trash.