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Finishing Lessons from a Small Shop Professional
by Chris Black

 

If you ask any woodworker what their weakest skill set is, they will probably say finishing. Perhaps it's because we've spent all our time mastering joinery and furniture design that we've neglected the art of finishing. As a result, we relegate ourselves to finishing with something someone recommended at a paint store that may or may not be applicable to what we're doing. Then when that doesn't work out, we fall back on slow-drying, slow-building wiping oil that at least gave us predictable results in the past. Start talking about coloring wood and we're completely lost. We'll try any old can of thin hardware store stain and pray for the best. How come we'll spend days on design and weeks on construction but give little consideration to the coloring process?

In my years as a small commercial shop owner, I've learned some valuable lessons about finishing, mostly through trial and error and well, disaster. When coloring a hard, close-pored wood like maple, try using dyes instead of pigment stains. We've all tried that can of off-the-shelf stain. We wipe it on. We wipe it off, and most of it comes off. What doesn't come off, blotches and splotches. The problem with pigment stain is that the pigment particles are too large. Without large, open, oak-sized wood pores to get lodged in, the pigment has no place to go. It never builds color or worse, it covers unevenly. Dyes, on the other hand, use color that is completely dissolved in its carrier. Therefore, dyes color closed-pored hardwoods much more evenly and with much greater control than pigment stains.

When coloring raw wood with water-based dyes, sand the piece with up to 220 grit sandpaper. Next, take a damp sponge and go over the portion to be dyed in order to raise the wood's grain. After the water dries, sand off the fuzzy fibers with 220 grit sandpaper. Now, wet the piece again with the sponge and immediately apply the dye in any manner you like. I generally rag it on. The water from the sponge acts as a wood conditioner and guarantees a uniform appearance with little chance of splotching. Try it, you'll be amazed.

To short-cut the procedure, put the dye down with a grey Scotch-Brite Hand Pad (196202) going with the grain. The abrasive pad will cut down the grain as it rises from the moisture in the dye, and you won't have to sponge and sand.

How about knotty softwoods like pines, spruces and firs? You can employ the same techniques listed before with good results, but for great results try this: First, seal the surface of the wood with a 1 lb. to 1 lb. cut of blonde dewaxed shellac(195863), paying particular attention to the areas around knots and endgrain. Once the shellac is dry, usually within a couple of minutes, lightly sand with 600 grit (CAMI) sandpaper. Apply another coat of shellac. Now, add any color of Transtint Concentrated Wood Dye directly into the liquid shellac. After stirring the dye/shellac mixture, brush or pad it on to color the wood. Start with about 10 or 15 drops of dye per 8 oz. cup of liquid shellac and test to see if you're pleased with the results. Because the color is completely sealed from the wood, there's no chance of splotching. Since you control the amount of dye added to the shellac, you readily get the depth of color you want. At this point, you can topcoat with just about any finish since most finishes are compatible with dewaxed shellac.

Speaking of shellac, it has become my go-to finish for everything I once finished with oil or nitrocellulose lacquer. For years the wood coating industry has maligned shellac as a weak, outdated and difficult to use finish. Some of this bad press may come from the fact that most shellac comes premixed in a can with relatively high wax content. Canned shellac usually ships as a 3 lb. cut which is too thick to apply easily. Zinsser now makes a premixed 2 lb. cut shellac (195831) which is quite good. But the key to getting the best results from shellac is to buy it dry in dewaxed flakes (195863), and only mix what you're going to use within a week or two. By combining your flakes with denatured alcohol in a blender, you avoid the 24-hour waiting period before the flakes dissolve.

As for hand application, I've found two methods that work well with shellac. Again, this presumes you've thinned the shellac to a 1 lb. cut (1 lbs. of shellac flakes to 1 gallon of alcohol or any reduced proportion). The first method is to pad the shellac on. Those familiar with French polishing will recognize this technique. Just wad up any absorbent cloth the size of a computer mouse and wrap it in a tight woven material like an old dress shirt. Squirt some shellac onto the pad and wipe it on. If the pad starts to drag a bit, put a drop of Camellia Oil (056460) in the center of the pad and be sure to let each coat dry for 30 seconds or so before laying on another coat.

The second technique involves a small, natural bristle, artist's fan brush. You can find them at art supply stores. By dipping the fan brush in the shellac and quickly whisking it onto the wood, you can effectively spread shellac where a bulbous pad wouldn't fit.

Another much-abused finish I've come to rely on is waterborne polyurethane, such as Gloss Ceramithane (195234). It's tough, dries quickly and it colors easily with Transtint Wood Dyes and Universal Tinting Colors (UTCs). Waterborne finishes are also easy to apply if you know how. When you brush or roll the stuff you get bubbles, craters and foaming, anything but a smooth finish. So why not rag it on? We apply everything else by wiping, so why not water-based topcoats? To really supercharge the event add just a little distilled water (no more than 5% by volume) to the sauce to thin it. Distilled water doesn't have minerals in it that can contaminate the finish and cause discoloration. By wiping on the finish you assure thin coats which dry quickly and keep dust nibs down. You can usually recoat in as little as 15-20 minutes.

What about those dust nibs? Most small shops don't have the luxury of a dust-free finishing room. In fact, most of us finish outside where bugs, pollen and other perils invade our films. Fast-drying finishes like shellac and waterborne polyurethane will help but you may have to consider finishing the finish. Yes, rubbing out. Look, it's not that complicated and besides, it is nearly impossible to get a perfect film straight from the can.

Step one is easy - let the finish fully cure before you start rubbing it out. Wait 24 hours for shellac and 2-5 days for water-based polyurethane, depending on the weather. Once the finish is cured, you will need to flatten it with 600 grit (CAMI) or P1200 grit (FEPA) sandpaper to get a uniform sheen or scratch pattern. Make sure you lubricate the paper with soapy water or mineral spirits to avoid cutting through the finish. Always sand with the wood grain, and stop frequently to check your progress. If your goal is a flat or matte finish, just wax and buff. You're done. The paste wax (00212 Staples paste wax) will fill the tiny scratches left behind by the sandpaper and give you a low luster finish much like one or two coats of oil. To achieve a satin/semi-gloss finish, skip the wax and rub Meguiar's Fine-Cut Cleaner (195895) on the finish with a clean, lint free cloth (195993). Make sure you buff with the grain. If you want a glossy finish, use Meguiar's Swirl Remover (195896). Each time you switch rubbing compounds, it is important to use a clean rag so you don't cross-contaminate the different levels of abrasive. Working with the grain will help minimize the appearance of fine scratches. Also, these materials cut fast, so there's no need for buffing machines or circular motions.

Finally, if you're going for a super glossy, wet-look shine, then Meguiar's Show Car Glaze (195897) will polish out any blemishes left behind. Remember, you can stop and wax anywhere along the process if you're happy with the level of sheen. Also, don't skip a step - you'll only make a mess and wonder why you're not getting anywhere.

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