Finishing provides the crowning touch, turning a raw box into a piece of furniture. The finish provides practical advantages such as protecting wood from stains, moisture, and drying out. It is also done for aesthetic reasons to bring out the grain, change the color provide a glossy texture and sheen, and enhance the natural quality of the wood.
Filling the gaps
Even the best woodworker will find small gaps here or there that need to be filled. In addition to gaps, there will generally be nail holes (make sure all nail heads are set), imperfections in the wood, damage from handling or accident, and saw holes (counterbores) to fill, There are several types of tinted wood filler available in stores, including acetone-based putty, oil-based crayons, and latex paste. To decide which type to use, read the various labels. Or better, solicit the advice of a salesperson after describing the wood, the nature of the filling to be done, and the type of finish you plan to use. If you are planning to paint the project, you can choose from a wide range of fillers. When using a clear finish or stain, both the color and the absorptive qualities of the wood must be considered.
Apply filler with a flat tool that will force the filler into the void, then will scrape away the excess. Large gaps or gouges will often require more than one application since many of the filler materials shrink as they dry.
Sanding
Most finishes immediately draw the eye to any flaws in the surface of the wood. Even paint won’t hide dents and gouges. The amount of time spent sanding, cleaning, and repairing the surface will be rewarded by the high-quality appearance of the finished piece.
Sanding is a three-stage process
The first stage, part of the cleanup and repair process, requires sanding with rough (80-grit) abrasive paper.
The second stage is to smooth with 120-grit or 180-grit paper. Do the last stage after sealing the case: This is to sand once more with very fine-grained paper (220-grit, or even 400-grit if using a finish such as lacquer that needs an extremely smooth surface).
Electric sanders can be very helpful in the first two stages of this process, but they leave oscillation marks or slight gouges. Many carpenters prefer to do the final (third-stage) sanding by hand because they can remove these flaws and do more exacting work.
Make sure the final sanding is done with, not against, the grain.
When properly sharpened, a cabinet scraper performs the same function as rough abrasive paper, leaving the finish of fine paper.
Sealing
Some carpenters like to use sealers to close the pores in the wood, smooth the surface, and reduce the absorbency. A sealer also helps wood take stain or paint more evenly, thus making the final finish easier to apply.
Sealer can also be used as an intermediary coat between the stain and the final finish. This prevents the two substances from bleeding into each other. (Occasionally a stain reacts to the finish and oozes into it.)
Using just a sealer can be an adequate finish for a particleboard case in a garage or utility room.
Table of Finishing materials
|
Description |
Use |
Application |
Comments |
Paint (gloss-finish enamel) |
An opaque, usually oil- or synthetic-based, liquid that dries to a hard finish |
For coloring and protecting wood |
Brush, spray |
Wood must be sealed or primed. Apply 2 or more coats. Sand with abrasive paper or steel wool between coats |
Varnish |
Clear wood finish. New synthetic varnishes are generally superior to traditional formulations |
For enhancing appearance of and protecting wood |
Brush, spray |
A durable finish that shows off the depth and grain pattern of the wood; resists moisture, including alcoholic beverages. Fairly slow drying |
Shellac |
Clear to slightly cloudy |
To protect raw or stained wood or as a sanding sealer or sealer under stain or paint |
Brush or spray |
Similar protective and visual qualities as varnish, but much faster drying. Clean up with ammonia and warm water (or alcohol) |
Lacquer |
Clear protective wood finish |
Very workable finish for fine furniture pieces |
Spray. Apply 3 coats rubbing with steel wool between coats. Leave final coat glossy or rub to a satin finish |
Use a wood filler to create a smooth base for lacquer finish; very fast drying time simplifies application of multiple coats |
Water based stains |
Powder or premixed liquid Well suited to enhancing the grain of premium hardwoods |
For tinting wood |
Rag brush or spray Dampen wood first |
These are stains designed to be used under a protective clear finish |
Pigmented oil stain |
Premixed liquid. |
For tinting wood. |
Apply with brush or cloth; wipe off excess. |
Well suited for darker tints on softwoods. When dry, apply a clear finish for protection. |
Alcohol or spirit stain |
Powder or premixed liquid |
Mostly commercial. Use a fine spray for shading |
Spray |
Use in spray applicator for shading and refinishing |
Penetrating oil stain |
Linseed or tung oil— based premixed liquid |
Tinting and protecting wood |
Brush, cloth |
Apply paste wax for added luster and protection |
Wax |
Paste compound that dries to a hard, lustrous finish |
To protect oiled finishes and for added protection |
Apply with a rag. Buff with a clean rag |
A wax finish over penetrating oil stain gives a warm, lustrous appearance |
Oil |
Ranges from translucent to dark-tinted liquid (linseed or tung oil) |
To color wood and give it a hard(er) surface |
Brush on; wipe off with rag |
Soaks into the wood giving a warm, lustrous appearance |
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