I've been hearing about wet sanding for a while now, and well I understand what it is - sanding with special sandpaper and water - but I'm at a loss as to when and why it should be used.

Anyone have an answer?

I do it on the primer before I paint to get it very smooth. THey make wet dry sand paper. It is very messy though. I would rather deal with the dust than the paste it makes. Sure makes it smooth though. You don't want to do it on straight balsa, makes a huge mess of things.

Flyboy is right (suprise! hehe) - you can basically wet-sand anything thats waterproof... cowls are another example. If you need to get something metallic polished, you can use "wet and dry" with oil (instead of water) before moving on to buffing compound.

SaviCatses:

I am sure you've been sanding and had to whack the paper against something to get the trapped particles out of the paper so you could continue.

Keeping the paper from clogging is the purpose of wet sanding - the paper doesn't clog up.

A side benefit is that as you continue the paper's cutting ability decreases, and you end up using what amounts to a polishing grit. Makes the surface very smooth, as pointed out by Flyboy.

Bill.

an easy way to limit the mud build up is to use alcohol instead of water. The alcohol dries fast and then just wipe down with a damp rag and presto, it is clean.

Dru.

Thanks for the replies, it's what I expected - just needed the reason why it would be done over dry sanding. I use a combination of wacking the sandpaper and a shopvac to unclog them