Sanding, Primering Car before Paint??

[roman]

You should definitely primer your car before painting!

Primer is basically an intermediate layer that's designed to stick to what ever is underneath, and give a good surface for the new paint to stick to.

Your paint will probably fall off, painting directly over existing paint!

The idea of wet sanding is that having a constant flow of water over the surface removes all of the dust particles etc that would normally be in between the paper and the surface...

If you are using a really fine grade of sand paper, the particles in between can be courser than the paper itself, and leave scratches.

So IMO it's only really important to wet sand when you are giving paint a cut back before polishing it up.