Painting and lacquering: how to paint a print

The procedure

A good result comes from a sequence: sand, fill, spray a primer, apply paint and finish with lacquer. Acrylic paint is usually applied with a brush or as a spray. There is an overview of lacquer on Wikipedia.

For a smooth surface the first step is sanding, without it the paint will highlight the layers. Apply sprays in thin coats from 20 to 30 cm and let them dry. A thick coat runs and melts sharp edges.

Materials and paints

• PLA and PETG can both be painted, but the smooth surface of PETG holds paint less well. A light scuff and a primer help.
• Solvents in some sprays can attack the surface. Test on a hidden spot.
• Heat. PLA softens at around 55 to 60 degrees, so be careful when drying paint with warmth.
• Health protection. With sprays use a respirator, as described on Wikipedia, and ventilate.

Print in colour straight away?

If you only care about colour, you do not have to paint. If you need several colours in one part, send a 3MF with colours assigned, which is what the entry on multicolour printing is about. Colours change automatically, the printer handles up to 4 colours, but every change adds time and a purge tower, so the print costs more.

A painted surface is finer and more even than printed colour, but it takes work. We do not offer this finishing as a service, parts arrive as the printer prints them.

What to check

If you plan to paint, leave room on the surfaces for a coat of paint, which is tenths of a millimetre and can fill fine details, threads and joints. For joints and moving parts, better not to risk it.

If the paint has to last outdoors, use a UV-resistant lacquer. PLA softens at around 55 to 60 degrees, so do not leave a part in a car in the sun.