How are lines applied to the ice of a hockey rink?
The ice is built up in stages to get to .75 total thickness. The first layer of ice is about a half-inch thick. At this point, lines and other markings are painted on the ice - literally painted on. The rink is then flooded and frozen again to get to the final thickness. The lines, logos, and markings show through and remain protected by the last layer of ice.