[mossguy]

For Paul:
The heart of a ice resurfacer is the 'conditioner', a large device dragged behind the vehicle. A large, very sharp blade, similar to those used in industrial paper cutters, shaves the surface off the ice, and an auger in front of the blade sweeps the accumulating shavings to the center of the conditioner, where a second auger (or, in early models, a paddle-and-chain conveyor) picks them up.
Directly in front of the blade, wash water is often sprayed on the ice by nozzles at either end of the conditioner. This wash water is confined inside the conditioner by the runners on either end and a rubber squeegee at the rear of the conditioner. The wash water is picked up by a vacuum nozzle, filtered through a screen, and recirculated. This washing process removes any foreign material that might otherwise become embedded in the ice surface. At the rear of the conditioner, a sprinkler pipe wets a cloth towel that lays down fresh water to fill the residual grooves, and forms a new ice surface.
Hot water (140°F to 160°F, 60°C) is frequently used where available because it melts and smooths the rough top layer of ice to create a flat, smooth surface. This water in many rinks is filtered and treated before being heated to remove any residual minerals and chemicals in the water. These chemicals and minerals could otherwise make the ice brittle or soft, give it pungent odors, or make it cloudy.

There was a really good show on Discovery or How Things Work or Modern Marvels that showed and explained this in great detail. Fascinating!

Best,
Tom