What grit sandpaper to use on plastic?

Sanding plastic requires a gentle touch and precise grit selection—unlike wood or metal, plastic is soft and prone to melting, scratching, or warping if sanded with the wrong tools.

For most plastic projects, begin with 180–220 grit sandpaper to tackle light scratches, remove mold lines, or rough up the surface for better paint or adhesive adhesion. This grit range balances efficiency and gentleness: it smooths minor imperfections without digging deep grooves into the plastic. Use this grit for prepping items like plastic auto parts, toys, or household containers before painting.

If the plastic has deeper scratches, scuffs, or excess material from molding, step up to **120–150 grit sandpaper** for the initial pass. This slightly coarser grit can handle more significant flaws, but avoid pressing too hard—excess pressure will cause the plastic to heat up and melt, leaving a gummy, uneven surface. Always follow this coarse pass with a 220-grit sand to erase the scratches left behind.

For the final finish, switch to **320–400 grit sandpaper** to create a smooth, polished surface. This fine grit is ideal for prepping plastic for high-gloss paints, clear coats, or decals. For a mirror-like finish on items like acrylic sheets or plastic lenses, go one step further with 600–800 grit sandpaper, followed by a buff with a polishing compound.

Never use grits coarser than 120 on plastic—they leave deep, permanent scratches that even fine sanding can’t fully remove. Additionally, opt for wet sanding with higher grits (320+) to reduce friction and heat buildup, which helps prevent melting and produces a smoother finish. Always sand in a circular motion with light, even strokes, and wipe the surface with a damp cloth between grit changes to remove plastic dust.

Match the grit to your goal: 120–150 grit for deep flaws, 180–220 grit for general prep, and 320–800 grit for a smooth, polished finish.