Sanding is one of the most important steps in costuming (for hard pieces only) and prop building. You can have a beautifully crafted prop with a great paint job but if the plastic shows scratches from sanding or an unsightly seam line, the effect is ruined.

When choosing sandpaper, you should use at least two different grits, if not three. The "grit" refers to how coarse or smooth the sandpaper is. The higher the number printed on the package, the smoother the paper will be. ie: 100 grit sandpaper is much more coarse than 400 grit.

Most jobs will need medium (usually 200) grit during the first stage of sanding. When sanding, use medium pressure and after you achieve a smooth surface, use a fine or very fine grit (usually 400) with medium then light pressure. Finish the piece with 600 grit or higher.

Now you're ready for what is called "wet sanding". Wet sanding will remove almost all marks left by the medium and fine sandpapers. Keep a container of water nearby and dunk your fine/very fine sandpaper in it. Shake off the excess water and begin sanding, using light to very light pressure. As the water dissapates from the sandpaper, dunk it in the container again. This procedure will take some time but, be patient! The end result is fantastic!