Painting guitar necks requires some preparation in order to make it ready to receive the paint. Most guitars will be varnished, and the varnishing will need to be thoroughly removed prior to starting.
Step 1 – Prepping the Neck
Sand the neck completely and make sure it is totally smooth. Begin with sand paper around 80 grade and progress to the smoothest 120 grade for the finest finish on your wood. Avoid pressing the rough grade sandpaper too hard into the grain. This will cause abrasions in the surface.
Step 2 – Priming the Neck
Spray the primer along the neck in a smooth and even fashion to avoid dripping. The primer should dry reasonably quickly but make sure it is properly dry before you paint.
Step 3 – Sanding
Sand the neck with fine grade sandpaper once the primer has thoroughly dried. Create a smooth bonding surface for the paint.
Step 4 – Painting the Neck
Spray the paint evenly along the length of the neck, again keeping it smooth to avoid dripping. Two coats may be required but judge best in your own case, how you wish the guitar to look.