Tip #20
Finishing & Finishing Techniques (continued)
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Final Finish

There are three types of protective coatings you can put on your project - an oil finish, a natural finish, or a synthetic finish.

Oil finishes will emphasize the grain and leave a flat, natural appearance. They darken slightly with age and take on a rich glow. They save time by priming, sealing, and preserving the wood in a single application.

There are several oil finishes available, each with a different purpose. Danish oil is the best all-round and can be used on a wide variety of interior projects. You can apply it over a stain, but there are also tinted Danish oils that will stain and finish the wood in one step. You can use it under a natural or synthetic finish to enhance the grain or tone, but you need to put a wash coat of one part shellac and one part alcohol over the hardened oil to keep it from blending with the final finish.

Tung oil was developed in the Orient in the 14th century to waterproof ships. It penetrates deep into the wood and forms a lasting moisture barrier. Some woods, like teak and rosewood, bleed off a finish and never seem to dry. Teak oil has special drying agents to solve this problem. It can also be used as a sealer before applying a natural or synthetic finish to resinous woods.

Eating utensils are commonly coated with vegetable oil, but this goes rancid and can affect the taste of your food. A good salad bowl finish is odorless, tasteless, and will not spoil. Use it on children's toys or whenever a non-toxic finish is desired. To apply an oil finish, wipe it liberally with a brush, saturating the surface. After 15 minutes, sand with 6/0 silicon carbide paper, lubricating the paper with more finishing oil. After a few minutes, remove all surplus oil with a soft, clean cloth. Allow to dry at least 12 hours.

Once hardened, wipe with on oil dampened rag and buff with a soft cloth. If you want, a liquid carnauba satin wax can be applied over oil finishes and rubbed to a soft luster.

Natural finishes, such as shellac, varnish, and lacquer, require a very good brush. Nylon and horsehair will not do; look for hog and badger brushes. The bristles of these brushes are naturally flogged (split), allowing you to load up more finish at a time and letting the finish flow evenly onto the wood surface.

However, to use these fine brushes most effectively, they need special preparation and care. Soak your new brush in solvent for an hour or so, then wrap it in paper and leave it wrapped for awhile before using it. When you first dip it into the finish, spin it rapidly to dislodge loose bristles - all new brushes have them. Dip to only one third the bristle length, and remove the excess finish by topping against the side of the can. Never wipe it on the rim; this loosens the bristles.

If you use your brushes often, keep them suspended in solvent. To clean and store them, slosh them in this solvent, press out and repeat. Wipe the bristles dry; then using a good detergent, wash the brush; rinse; wrap the bristles in paper and hang it up, bristles down.

To apply a natural finish, brush with the grain in long, sweeping strokes, lopping each stroke. The exception to this rule is varnish, which is brushed on first across the grain, followed immediately by light strokes with the grain. Don't apply these finishes in temperatures below 65° or in extreme humidity. Lightly, wet-sand with 7/0 - 10/0 paper between each coat and wipe clean. If you want a high gloss finish, rub and polish the final coat with pumice or rotten-stone, then apply a good carnauba wax and buff.

Synthetic finishes, like polyurethane and acrylic, also benefit from a good brush and are applied in much the some way as natural finishes. The main advantage in using synthetics is that they are often more durable and designed to serve a wider range of special purposes than natural finishes.

Some synthetic finishes can also be poured onto a wood surface and left to harden, making your project look as if it were enclosed in glass. This is an extremely attractive effect, especially for: table tops, counters, and plagues. Fiberglass resin finishes work best for this type of application.

To use, mix the resin with the hardener as directed by the manufacturer. Pour this mixture over your project (one surface at a time), then tilt it this way and that until the finish is distributed evenly. Keep the surface level while the resin cures. To remove bubbles, blow gently across the resin while it is still liquid. These resins can also be used to adhere and imbed dried flowers, coins, decals, news clippings - almost anything - on a wooden surface. The only requirement is that the imbedded object be completely free of moisture.

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