A teacher at a recent conference turned us on to this idea: Rather constantly changing color filament spools, they print everything in white PLA. They then let the students color their prints using permanent markers.
It save a lot of time and allows the students to be more creative, adding multiple colors per print. It’s also cheaper than trying to stock 8-12 spools of different colored filament.
You might want to experiment with different types of markers. This video uses Sharpie oil based paint markers. Others suggest using regular Sharpie permanent markers or acrylic paint markers, which dry much faster. Let us know what works best for you and we’ll post it here.
We’ve heard that, if needed, a coat of clear varnish from a spray can can help prevent colors from smudging or wearing off.