1. How long should I leave between coats?
Drying time is affected by temperature. As a rule of thumb for nitrocellulose lacquers, apply 3 coats over a 30 minute period, then leave to dry for about 6 hours, or overnight. Then apply a further 3 coats and repeat until you have built up sufficient lacquer or paint.
2. How long should I leave the lacquer to dry before buffing?
Standard Nitrocellulose takes a long time to harden whereas Pre-Cat Nitrocellulose has a catalyst to speed up the hardening process. Pre-cat can be ready for cutting back after 7-10 days whereas standard nitrocellulose may take as long as 4 weeks.
3. To sand or not to sand between coats”, that is the question?
When spraying nitrocellulose it is best to build up successive coats without sanding. Only sand if dust, a fly, or a run appears on your handy work. By building up successive layers you are creating one “thickish” layer of lacquer. When the whole thing has hardened off, cut it back to create a level and smooth finish. The better you get at spraying, the fewer coats you will need before flatting back.
4. How many coats should I put on?
It depends how cold it is. Personally I wear a thick fleece when it’s cold. Seriously though; it depends. In warm weather the lacquer dries faster, almost as soon as it lands on the wood. You can apply a thicker coat without developing a run. In cold weather thinner coats will be needed so that the slower drying lacquer doesn’t run. 4 thick coats or 6-10 thin ones should cover it. Pro sprayers regulate the temperature of their spray booths so they get consistent results. If you are working in a shed, or garage, it’s a question of trial and error.
5. Will the paint or lacquer affect the tone of the guitar?
If it is an electric guitar no. You have a mass of wood, pickups and an amp. A few coats of paint won’t make a jot of difference.
Acoustic instrument? Maybe. A lacquer or paint finish on an acoustic instrument is designed to protect the wood from dirty fingermarks, grease, tomato sauce spills etc. The guitar body wood is 1.5mm -2.5mm thick. If you apply 0.5mm of lacquer, it may well affect the tone. In reality the lacquer is microns thick so it won’t affect the instrument. The construction and choice of materials has by far and away the most influence on tone.