French polishing is a traditional technique for building a thin, glossy shellac finish with a pad. It’s a method, not a product, and it takes practice. It suits pieces that were originally finished in shellac. Check the piece’s value and original finish first, because French polish replaces the surface you have.
When French polishing suits a piece
French polish is a good match for many pre-1920 pieces that were originally finished in shellac, and for repairs that need to blend with existing shellac. It isn’t a good first choice for a valuable antique with an intact original finish. For those, clean and revive first. If you’re unsure, ask an appraiser or conservator. The antique furniture restoration guide explains the wider order of work.
Materials
- Dewaxed shellac flakes. Super blond, blond, and lemon are light. Orange and garnet are warmer.
- Denatured alcohol as the solvent.
- A pad. A wadding core of wool or cotton, wrapped in lint-free cotton or linen, with a smooth, wrinkle-free face.
- A drop of mineral oil for the pad. Traditionally, raw linseed oil was used.
- 4F pumice for filling open-pored woods.
- Naphtha for removing wax or silicone before you start.
Mix the shellac
A 1-pound cut uses 1 pound of flakes per gallon of alcohol, about 120 grams per litre. Heavier cuts of 1.5 to 2 pounds are used for building body. Mixed shellac keeps for roughly 6 to 12 months, so mix only what you’ll use, and keep it sealed.
Make the pad
Wrap the wadding in lint-free cotton or linen, and gather the cloth at the back so the face is smooth and wrinkle-free. Wrinkles leave marks. Store used pads in a sealed metal container or under water, since oily pads can catch fire on their own.
Prepare the wood
Remove any wax or silicone with naphtha, because contamination stops shellac from bonding well. Cleaning old wood furniture before refinishing explains the process. On open-pored woods such as mahogany, walnut, and rosewood, fill the grain with 4F pumice, applied through the pad.
Fadding, bodying, and spiriting off
French polishing has three main stages:
- Fadding lays the first light coat with fast, sweeping strokes.
- Bodying builds the finish with circular and figure-eight strokes. A slightly heavier cut can help as the layers build.
- Spiriting off passes a nearly dry alcohol pad lightly over the surface to clear oil and smooth the finish.
Keep the pad moving. Glide on and off the surface, and never stop the pad on the wood, since that leaves a mark.
Work in sessions
Most jobs take several sessions over several days. Let each session dry overnight. Before the next session, remove any oil film, sometimes called oil sweat, with a clean, nearly dry pad. Too much oil makes the finish smear and slows the build.
Harden, then finish
Let the polish harden for one to two weeks before you wax or rub it out. Shellac must dry hard, or it will mark. Once it’s hard, you can rub the surface or apply a thin wax.
Common problems
- Blushing, a white haze, can happen when humidity is above about 70 percent. Work in a drier room, let the piece dry, and rework the area.
- Smearing comes from too much oil or too much pressure.
- Streaks usually come from a wrinkled pad or from stopping the pad mid-stroke.
French polish also marks easily from water, alcohol, and heat, so protect the finish once it’s done.
Repairs and blending
French polish is repairable. New shellac bonds to old, so you can touch up scratches and blend repairs into the surrounding finish. Use a fresh pad, and work carefully near the edges.
Safety
- Shellac and denatured alcohol are flammable. Keep flames and sparks away, and ventilate well.
- Oily pads can catch fire on their own. Store them in a sealed metal can or under water.
- Wear gloves to keep shellac and alcohol off your skin.