The grit of sandpaper to use before painting a car depends on the condition of the surface and the type of paint job. Here are some recommendations from the search results:

• 24 to 36 grit: Use this grit range for rough areas along the surface that need to be flattened out, such as on an older car with numerous overcoats.

• 80 grit: This grit is useful for cars with more than one prior paint job, as well as vehicles with light corrosion around the edges.

• 150 grit: On cars that have a smooth, single layer of paint, 150-grit sandpaper can do an adequate job of stripping the paint to reveal the metal surface.

• 320 to 500 grit: Use a finer grit sanding paper to remove the paint. If youre not stripping it down to the bare metal, youll need to feather the edges.

• 400 to 600 grit: Use this grit range to sand the paint to prep the existing paint surface for the new coatings to be applied.

Its important to note that the grit of sandpaper to use also depends on the type of sanding application in the automotive industry. Sandpaper grit refers to the number of abrasive particles per square inch of a sheet of sandpaper. The lower the number, the fewer abrasives present, making it courser sandpaper. The higher the number, the more abrasives present, making sandpaper finer.