TOOL
French polish
A shellac film applied by hand, one thin layer at a time.
| Material | Shellac flakes in alcohol (meths) |
|---|---|
| Cut | 1.5 – 3 lb cut, depending on the stage |
| Pad | Cotton wadding wrapped in fine linen |
| Lubricant | A drop of oil to stop the pad sticking |
| Sessions | Many short sessions over days or weeks |
| Sheen | Deep gloss, or rubbed back to satin |
| Build | Dozens of thin layers, each partly dissolving the last |
|---|---|
| Bodying | The main build stage, in figure-eight patterns |
| Spiriting | A pure-alcohol pass to flatten the surface |
| Glazing | A final thin session for gloss |
| Cure | Days to harden fully before handling |
| Price band | Low materials, high labour |
French polish is shellac applied with a pad rather than sprayed. The pad is charged with shellac and a little oil, and worked over the surface in overlapping patterns until the film builds. The result is the thinnest possible finish, which is why classical guitars use it — nothing gets between the wood and the sound.
It is slow, physical work and the finish is fragile compared with lacquer: heat, alcohol and water all damage it. But it is repairable in place with the same pad, and it can be built on a finished instrument without stripping it.
At this stage
French polish is done after the instrument is assembled and strung, or just before. It is a bench skill that takes practice on scrap before it goes anywhere near an instrument.
Suits these instruments
- Classical
- Flamenco
- Parlour
- Steel-string acoustic (traditional)
Works with
- Shellac flakes
- Sanding sealer
- Grain filler
- Polishing pads
- Methylated spirit and shellac are flammable. No flames, no smoking, and keep the workspace ventilated.
- The solvents are intoxicating and harmful over long exposure. Ventilate the room and take breaks.
Working notes
- Practice on a scrap board until you can build a film without streaks.
- Less shellac on the pad, more sessions. A wet pad makes a mess.
- Keep the pad moving. A pad left still on the surface melts the finish under it.
- The oil is a lubricant, not an ingredient. Too much leaves a hazy film.
Related
Nitrocellulose lacquer
The traditional finish: thin, clear, and easy to repair.
Sanding sealer
The first coat that stops the wood drinking the finish.
Glue
Three glues, three jobs, and none of them interchangeable.
Clamps
Enough of them, and enough reach.