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AW Extra 12/27/12 - 12 Finishing Tips

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12 Finishing Tips

Good finishers have lots of tricks up their sleeves. Here’s a handful from Bob Flexner, one of the nation’s foremost experts.

By Bob Flexner



1. Add depth by glazing

Glazing accentuates the three-dimensional look of moldings, carvings, turnings, and raised panels. A glaze is simply a thickened pigmented stain—thickening it reduces runs on vertical surfaces. Gel stain works well as a glazing material.

Glazing is always done over a sealed surface, meaning over at least one coat of finish. After the first (or second) coat of finish has thoroughly dried, wipe or brush on the glaze. Allow the solvent to evaporate so the glaze dulls. Then wipe off most of the glaze using a rag or brush, leaving some of the glaze in the recessed areas of your project.

After the glaze has dried, apply at least one additional coat of finish. This prevents the glaze from being rubbed or scratched off. Never leave glaze thick; the finish won’t bond well to it.

Click any image to view a larger version.




2. Clean brushes with lacquer thinner

The standard procedure for cleaning a varnish brush is to rinse it a couple of times in mineral spirits, and then wash repeatedly in soap and water. I take an extra step: After the mineral spirits, I rinse my brush in lacquer thinner. Commercial brush cleaner works well, too.

Lacquer thinner or brush cleaner quickly removes most of the oily mineral spirits. This step makes washing with soap and water easier and quicker. You’ll usually need only one or two soap-andwater washings to achieve a good lather, which indicates the bristles are clean.

Remember to use adequate ventilation when you work with lacquer thinner or brush cleaner.




3. Keep everything clean

Reduce dust nibs by keeping your project and work area clean. If you are finishing in the same area where you’ve been sanding, allow time for the dust to settle and then vacuum the floor. Vacuum your project using the brush attachment. Use a lint-free cloth to remove any dust that remains in the wood’s pores.

Just before you begin brushing or spraying, wipe your hand over horizontal surfaces to be sure they are clean. You will feel dust you don’t see. Your hand will also pick up small bits of dust that may have settled after you did the major cleaning.




4. Bury raised grain

Water-based stain and finish raise wood fibers, making the wood’s surface feel rough. Many folks suggest prewetting bare wood with water and sanding the raised grain after the wood dries. This method is fairly effective, but there’s an easier way.

Skip the prewetting and bury the raised grain in the finish. Burying simply means encasing the raised grain in a layer of finish. Apply the first coat of water-based finish and then sand it smooth, raised grain and all.

You can use the same approach with a water-based stain, which also raises the grain. The stained surface may become rough, but don’t sand the stain. Apply one coat of finish and then sand. Be careful not to cut through the finish into the stain.




5. Ebonize with black dye

The easiest way to make any wood resemble ebony is with black dye. Unlike pigment, which is the colorant used in paint, dye has transparent properties. You can make wood as black as you want and still see the figure of the wood through the dye. I prefer to use walnut when ebonizing because its grain is similar to that of real ebony.

Dyes come in many forms. I prefer to use powdered water-soluble dyes because they offer more time to wipe off the excess. If the wood doesn’t become black enough with one coat, make a more intense color or apply one or more extra coats. Allow the dye to dry between coats.

 

Source

Tools for Working Wood, toolsforworkingwood.com, 800-426-4613, Lockwood water-based ebony black dye, 1 oz., #LW-WMIS.327.




6. Reveal flaws in reflected light

Something is bound to go wrong when you brush or spray. You may get runs, drips, spills, skips, orange peel—you know the list. The trick is to spot these problems in time to correct them. Reflected light is the answer.

As you finish, move your head so you can see the surface in a reflection of an overhead light, a window, a handheld light or a light on a stand. The reflection’s shiny surface will show you the exact condition of the finish.




7. Find dried glue

Dried glue causes spotting when you apply a stain or finish. Most glue dries clear, though, so how can you tell where it is? Water or mineral spirits reveal all.

Before a final sanding, wet the entire surface with water or, if you have adequate ventilation, with mineral spirits. This will make the wood darker, but glue drips, spills and fingerprints will be easily identifiable because they’ll appear as a light color. How does this work? Glue seals the wood’s surface. Water or mineral spirits won’t penetrate the glue spots, so those spots won’t become as dark as the rest of the wood.

Water will soften dried glue, making it easier to remove with a card scraper or a chisel. You can also wash off glue by scrubbing with a rag and hot water. When you’ve removed the glue, sand with the highest grit of sandpaper you used on the rest of the project.




8. Spray unseen parts first

Spray the less seen and less touched parts of your project first. Spray the most important surfaces last. This way, overspray will land on parts where it really won’t matter.

Overspray is the mist that bounces off an object or sometimes misses the object altogether. The mist floats in the air and eventually lands somewhere, often back on the project itself. Overspray makes surfaces it lands on feel rough.

Here’s how to proceed on a table or chair. Spray a table’s legs and rails before its top. Turn a chair upside down and spray the insides of the legs and insides and bottom sides of the stretchers. Stand the chair upright and spray the legs’ outsides and the stretchers’ tops and outsides. Finish by spraying the backside of the chair back, the arms and finally the front side of the back and the seat.




9. Sand more on end grain

End grain can turn very dark when stained. More often than not, the problem is that the end grain is still somewhat rough from sawing. The same sanding procedure that you used on the rest of your project is often inadequate to prepare end grain for staining.

To remove saw marks, begin sanding end grain with a coarser paper than you are using on the side grain. An 80-grit sandpaper is usually coarse enough. When you have made the end grain smooth with this grit, work up through the grits just as you do with side grain, finishing with the same grit you used to finish-sand the side grain.

You can make sanding any end grain easier by sealing it with thinned glue or finish before you begin sanding. Thin a white or yellow glue with about three parts water. Thin any finish by about half with the appropriate solvent. Both methods stiffen the fibers, making them easier to cut off with the sandpaper.




10. Reduce blotching in pine

Staining pine can be a risky business. Some stains cause pine to look blotchy with irregular light and dark areas. Wood conditioners are widely used to reduce blotching prior to staining. For pine, though, using gel stain is far easier, more effective and more predictable than applying wood conditioner for achieving the intensity of color you desire.

In my experience, gel stain is not as effective at reducing blotching on hardwoods, such as cherry, birch, maple or poplar. For these woods, use a wood conditioner before staining.




11. Let wood conditioner dry thoroughly

Wood conditioners eliminate blotching much better when they’re allowed to dry thoroughly. I believe the drying times recommended by manufacturers should be lengthened.

The directions for most solvent-based wood conditioners instruct you to stain within 2 hours of application. These conditioners are actually a varnish, which takes at least 6 to 8 hours to dry in a warm room. It’s better to wait overnight before you apply stain.

Most cans of water-based wood conditioners say you can stain 30 minutes after applying the conditioner. I think you should wait at least 2 hours.




12. Thin the finish for better leveling

Thinning a finish reduces brush marks and orange peel, which are two common problems when you’re brushing or spraying. If the finish is thin enough, you can entirely eliminate these defects.

Use the appropriate thinner to thin the finish. Begin by thinning about 10 percent. Thin more, if needed, to achieve better leveling. For water-based finishes, it’s best to use the manufacturer’s “flow additive” to thin the finish. Adding a little water may help somewhat, but if you add too much, the finish will bead on the surface.

All finishes can be thinned. Sometimes instructions say not to thin a finish, but this is done to comply with EPA volatile organic compound (VOC) laws so less solvent evaporates into the atmosphere. No harm is done to the finish if it is thinned. Thinning does make a finish more likely to run on a vertical surface and to build at a slower rate, however. You may have to apply more coats than usual.




This story originally appeared in American Woodworker January 2007, issue #126.

January 2007, issue #126

Purchase this back issue.

 


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Comments

86bronco wrote re: 12 Finishing Tips
on 09-12-2009 10:44 PM

nice!