3D printing materials are often solid colors, and produce a solid color object. Adafruit recently released a Youtube video demonstrating how to Hydro-Dip simple 3D projects. It’s an easy, but visually rewarding technique that allows the user to add printed patterns and colors to a solid 3D object. No need for painting when you can Hydro Dip your projects.
Hydro Dipping is also referred to as Hydrographics, or Inket Water Slide Decal Transfer, is similar to a marbling technique used with paint. Hydro Dipping involves dissolving the pattern into a container of water, and then submerging the 3D printed object in the water in order to transfer the pattern. The trick is the special ink, which allows the transfer from the sheet of paper, to the surface of the water, to finally your 3D printed object. It’s important to use a large container of hot water so the ink is not caught in small crevices of the container, something that could potentially damage the quality of the graphic.
The most important piece of equipment that is needed for the Hydro Dipping method, in fact the only thing you need that you might not already have, is a special kind of paper called Water Transfer Paper. One side of this paper is an adhesive matted backing, which can be peeled off, and the other side is a PVA film. Due to its solubility, PVA is also used for constructing support structures for 3D printed objects, which are dissolved afterwards to leave the finished object behind. In this case the film gradually dissolves in water, leaving the printed ink floating in place on the surface, transferring to your 3D printed object as it is submerged.