Shellac

A sealer coat of dilute shellac locks the wood fibers In place. A light scuff sanding with fine sandpaper cuts the fibers off smoothly.

the top coats, while others prefer a 3- or 4-lb. cut. I feel most comfortable with a 2-lb. cut at this point. Depending on the cut you use for the top coats, you'll need to apply anywhere from three to ten coats to build up a sufficient finish.

Depending on the weather, you should be able to apply an additional coat every few hours. If the weather is dry enough, you might be able to apply three or four coats each day. Shellac dries more slowly in cold temperatures and high humidity and faster when it's hot and dry. Each new coat of shellac will begin dissolving the previous coat, so it's important to avoid working the brush back and forth over the same area too much, or you'll remove as much as you're putting on. Because of the rapid drying, wait until the next coat to cover missed spots. Otherwise, you risk "dragging" the already tacky film, like pulling the skin that forms on a cup of hot chocolate.

For a high-class, mirror-flat finish, you'll want to dry sand the shellac very lightly with 320-grit sandpaper after every two or three coats. Use an open coat, light-gray, silicon carbide paper, like 3M Tri-M-ite or Norton No-Fil Adalox. This sandpaper has a zinc-stearate coating, which acts as a lubricant.(See Mav/ June. 1988 AH'.)

Shellac is reversible, which makes a shellac finish easy to repair. Gaps in the finish or damage caused by spilled alcoholic drinks can be filled in with more shellac and leveled flat by sanding. No line will show-where the new shellac meets the old. Runs or sags can be sanded or scraped flat. Gouges can be filled by melting solid shellac sticks—sometimes called burn-in sticks—into the gash, or by dripping in liquified shellac a layer at a time.

An old shellac finish can always be renewed by French polishing —a technique of applying shellac with a cotton pad. (See March/April, 1989 AW.) French polishing gives superior results, because it leaves no brush marks or rubbing-out scratches on the surface.

Old shellacked surfaces can also be revived by re-spreading the surface with alcohol and/or recoating with fresh shellac. Another alternative is to strip off the old finish with alcohol —a clear advantage over the noxious fumes of the methvlene-chloride based strippers necessary for Type 2 (reactive) finishes. You can tell if an old finish is shellac by dabbing alcohol on a small spot-shellac will turn sticky within seconds. A

Rubbing with 0000 steel wool will give a rubbed satin look. Switch to pumice with water or oil for greater gloss. For maximum gloss, finish up with rottenstone.

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