Sanding 3D printed parts: getting rid of layer lines

Remove support remnants and seams with a knife or file, then take down the layer lines by hand with P120 to P180. Sand small parts on a block, not with your finger – otherwise the edges get rounded. Power sanders are too aggressive for most prints.

PLA softens at around 60 degrees. Light pressure, short strokes, breaks. From P400, sand wet: the water cools and binds the dust. Always wet-sand resin prints and wear gloves while you do – uncured resin irritates the skin.

If you want to paint, spray on a filler primer after P240, sand it with P320 to P400 and paint. For a smooth surface without paint, carry on wet sanding up to P600 or P800.