Stripping an old finish

Removing an old finish — shellac, varnish, or paint — before a piece is refinished. The method (solvent, scraping, or both) depends on the finish, the condition of the wood, and whether the original patina should stay.

The first step is to identify the finish. Shellac dissolves in alcohol; nitrocellulose lacquer and polyurethane need a stronger chemical stripper. For shellac and older, softer varnishes, a cloth dampened with denatured alcohol softens and lifts the finish gently while leaving the wood underneath. For tougher finishes, a chemical paint or varnish stripper is laid on thick, left for the time the maker specifies, and lifted with a plastic scraper or a dull blade so the wood is not cut. Sanding is a poor first method on antiques — it erases patina and carved detail. For the last of the residue, fine steel wool (0000) or a synthetic pad with a little remaining solvent cleans the surface. The work needs good ventilation, gloves that resist solvents, and disposal of the waste as chemical waste, not down the drain.

Technique

French polish

An old finishing technique that uses shellac dissolved in alcohol, laid on in many very thin coats with a cloth pad, to build the deep, “wet” gloss associated with antique furniture.

Term

Patina

The layer of wear and sheen that wood gathers over the years. To collectors it is an asset, not a flaw: original patina raises value, and removing it can damage that value badly.

Term

Reversible restoration

The founding principle of professional restoration: every repair should be one that can be taken apart in the future without harming the original.

Care guide

Cleaning an antique finish properly

Do not use household cleaners or commercial furniture spray — silicone and solvents damage shellac and an original finish. Dust with a dry microfiber cloth, and only occasionally with a cloth that is barely damp. To refresh the sheen: a thin coat of natural wax (beeswax or carnauba) once or twice a year, in gentle circles.

Sources

Wood finishing — Wikipedia

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