What is the best kind of paint to use on an acoustic guitar?

If you just have to do it... 1. Remove the old finish, if you can, without damaging the wood. This means varying effort depending on the current finish. Start by testing with denatured alcohol on a very small area; if the finish comes off, stop. No, really. It's likely finished with shellac, and deserves better treatment. Next, try a little acetone on a similar small spot. If the finish softens or lifts, odds are it's lacquer. If you absolutely HAVE to paint it, mix up some spirit shellac, and spray on a few thin coats. After you've taped off the sound hole, bindings if any, and fretboard, that is. Block sand down to about 220 grit, using just enough pressure to cut through the orange peel. If you press too hard, you'll sand the top thinner over the braces than between them, and that sucks. Now you've got choices. Use nitro lacquer if you can protect yourself from fumes and contact: if you can smell it, you're doing damage. If you're masked and can taste it, stop. Wait a few weeks, get fresh filters for your mask, spray two thin coats and stop. That leaves a few choices for appearance at the expense of sound: enamels and acrylics. If it's an artistic job, go for acrylics, thinned about 20% with alcohol if you're spraying or water for brushing. Don't go over areas already covered unless you like brush strokes. Hang it up from a tuner hole (you did remove them, yes?) And let it cure at least a week; a month would be better if you're hoping to sand and topcoat. Good luck.

There's no good kind of paint to use on an acoustic guitar top; paint is way too thick to produce an acceptable finish. Painting an acoustic will definitely affect the tone negatively.

I recently painted my acoustic guitar and used acrylic paint. It definitely dulled some of the low-end of the sound, but I strung it 'Nashville Style' to try to take advantage of the higher-end aural qualities of the guitar. Turned out great! Here's a video I made outlining the process of how to paint an acoustic guitar: If you're looking for a more detailed tutorial on how to paint an acoustic guitar, check out my blog post with step by step instructions: http://nickcamillo.com/how-to-paint-an-acoustic-guitar-nashville-tuning/