[bvia]

The reason you wetsand a paintjob is so that the sandpaper lasts longer. There's really no other reason and it's suggested by some that newbies don't try it until they are comfortable with dry sanding.

The only difference between dry sanding and wet sanding is the wetting agent. For this you would want to add a drop or two of dishwashing liquid (unscented and non-aloe added formula) to a cup of tepid water. The wetting agent allows the particles that are sanded off the surface of the paint to NOT be embedded into the sandpaper's surface and therefore "last longer". An added bonus is that it helps to reduce the friction across the painted surface and reduce gouging somewhat.

Some prefer to do their wetsanding under a running tap using the constant water flow to wash the particles away. I prefer to do mine with a cup under a nice, strong light, using a dry towel to constantly dry the sruface and check my progress.

hth,
Bill