will someone explain wet sanding

ive read alot about fiberglassing and finishing it and im about to glass my doors and put 3 componet set in them but when it comes to finishing it i dont under stand the wetsanding ive read about

thanks

Wet sanding is normally done with the finer grits. Dry sanding is usually for the coarser grits. The water (or oil when doing different steel work) helps to keep from clogging the paper and helps flush away the sanded off material. If you have a rough surface do not just jump in with the finest grit to sand it down but work your way from the coarse grit to the finer grits. If you are doing large flat panels use a block to back up the paper so it will keep the paper from flexing and help flatten the surface. You sometimes have to be imaginative and if you need a longer block, take a paint stick or a piece of straight thin wood or steel and wrap the paper around it and it will get the panel flatter and quicker than with a small block. I have also found out that adding a few drops of dish washing liquid in a gallon of water helps to keep the paper from clogging. Use only water for wet sanding unless it is a steel or stainless part.

Jim/Saint Louis