Once the planets had dried I coloured them. Sharpies work well with this type of clay. I made Mercury grey, Venus yellowy-white, Earth blue and green, Jupiter yellow with brown and green stripes, Saturn yellowy-white, Uranus green and Neptune blue. The colours turned out really vibrant which didn't quite suite an orrery. So I mixes some gold paint with a pale pink nail polish and covered the planets to give it an antique-like appearance. When the paint had dried I glued the planets to the wire with super glue (unfortunately the glue seems to interact with Sharpies and cause Saturn to bleed a red colour).