TOOL
Nitrocellulose lacquer
The traditional finish: thin, clear, and easy to repair.
| Type | Nitrocellulose, solvent-borne |
|---|---|
| Solids content | Roughly 15 – 25 percent by volume |
| Coats | 12 – 20 thin coats, sanded between |
| Dry to touch | Minutes; recoat within hours |
| Full cure | 2 – 6 weeks before final buffing |
| Sheen | Gloss, satin or matt |
| Film thickness | 0.10 – 0.20 mm finished |
|---|---|
| Spray setup | HVLP, 1.2 – 1.4 mm nozzle, 2 – 3 bar |
| Thinner | Lacquer thinner, matched to the product |
| Temperature | 18 – 24 °C; humidity under 60 percent |
| Sandpaper | 400 – 2000 grit, wet for the final stages |
| Price band | Moderate; the equipment is the expense |
Nitrocellulose lacquer is the classic guitar finish. It goes on as many thin coats, each of which melts into the one below, producing a film that is thin enough not to damp the sound and clear enough to show the wood off. It also repairs invisibly — a new coat melts into the old.
It is also slow and hazardous. A full nitro finish takes weeks of spraying, curing and buffing, and the solvent is genuinely toxic, flammable and subject to air-quality regulation in many places.
At this stage
Finishing is the last stage and the one that cannot be rushed. Most finish faults come from spraying in the wrong humidity or from buffing before the film has cured.
Suits these instruments
- Steel-string acoustic
- Electric
- Archtop
- Bass
Works with
- Sanding sealer
- Grain filler
- Spray equipment
- Buffing compounds
- Nitrocellulose lacquer is highly flammable and its solvent is toxic. Spray outdoors or in a properly extracted booth with an organic-vapour respirator, never in a garage with the door shut.
- Solvent vapour is heavier than air and pools at floor level. Ventilate low as well as high, and keep all ignition sources out of the area.
Working notes
- Spray many thin coats. One heavy coat sags, blushes and takes days to dry.
- Watch the humidity. Above 60 percent the finish blushes white as the solvent traps moisture.
- Wait the full cure before buffing. Buffing soft lacquer leaves swirl marks that never come out.
- Keep the film thin. A thick finish deadens the sound and cracks at the joints.
Related
French polish
A shellac film applied by hand, one thin layer at a time.
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.