French Polish: Pad Technique and Process
French polish is a traditional furniture finish consisting of shellac (a natural resin secreted by the lac insect) dissolved in denatured alcohol, applied with a pad (also called a rubber or muñeca) using a specific rubbing technique that builds an extremely thin, high-gloss film with exceptional clarity and warmth. French polish is the traditional finish for fine antique furniture, violins, and high-end piano cases. Its disadvantages — susceptibility to heat (white rings from hot glasses), moisture (white or black water marks), and wear — make it inappropriate for utilitarian pieces but perfect for formal decorative furniture. Surface preparation is critical: sand progressively through 220-grit, then 320-grit, raising the grain with a damp cloth between each grit. Open-grained woods (oak, mahogany, ash) must be pore-filled before polishing — pumice powder mixed into shellac (or commercial grain filler) is worked into the pores in circular motion and then wiped off the surface, leaving only the pores filled. Without pore filling, shellac sinks into pores and requires many more applications to achieve a flat surface. The pad is made by wrapping a cotton wadding core (pre-loaded with shellac) in a lint-free cotton outer cloth (usually bleached linen). The pad is charged (loaded) by unfolding the outer cloth and applying shellac to the wadding core — never directly to the outer cloth face. The pad face should be damp but not wet. A drop of linseed oil on the pad face lubricates it so it glides without dragging on the fresh shellac surface. Bodying coats: working in small oval and figure-8 motions, apply many thin passes of shellac. Each pass deposits a thin film; previous films dissolve slightly and re-amalgamate, building a seamless surface. Apply 20–30 bodying sessions over multiple days. Spiriting off (final gloss): remove the oil lubricant by using a nearly-dry pad charged only with pure alcohol, making long straight strokes. The alcohol evaporates the linseed oil residue and levels the surface to a mirror gloss.