sanding

[jamores23]

how do you determine when to dry sand, damp sand, and wet sand?

[C. Charles Hahn]

What you're describing are three separate methods of sanding, all of which are useful to have in your skill set. The question is, what job are you doing?

[jamores23]

lol my question is how would you determine which technique your going to use? why would you use dry sanding instead of damp or damp instead of wet ?

[C. Charles Hahn]

lol my question is how would you determine which technique your going to use? why would you use dry sanding instead of damp or damp instead of wet ?

First order of business is to learn and understand what damp and wet sanding are and how to use them:

http://www.autogeekonline.net/forum/wet-sanding-cutting-buffing/25915-damp-sanding-tools-tips-techniques-mike-phillips.html

As for dry sanding, you don't typically want to use that technique if what you're doing is final finish sanding. Fine grit paper loads up quickly when used dry, and loaded paper is not only ineffective but it also can instill pigtails and RIDS into the finish. For the most part you'll find dry sanding used if you have runs or dirt nibs in a fresh finish that are isolated to a small spot repair. Otherwise it's for body work and pre-paint prep.