Sand with high water content is frozen by sub surface piping containing bribe solution (glycol or similar).
Water is flooded over the reasonably level sand and then spray painted (white) with water based paint which also freezes (two -four coats)
This is flood again and frozen repeatedly to build a buffer over the white paint.
Lines, goal crease, face off dots and hash marks painted by brush using coloured wool as edge guides, these are sprayed lightly by hand (think garden weed killer bottle). Once sealed well enough to not be disturbed by flood water the pad is flooded a couple more times and frozen.
Next logos are painted (often free hand but guided by an image projected from a tower above). Spray these in same way as line markings then begin flooding repeatedly to obtain a significant depth to whole pad.
