Ice preparation & ice resurfacer (Zamboni)

Why the ice needs to be prepared

After a period of ice hockey or an hour of public skating, the ice is scratched, full of grooves and covered in snow. Blades cut out fine shavings with every stop and turn. On this ice the puck glides unevenly and skaters lose their grip. That is why the ice resurfacer drives over the surface during breaks.

How the ice resurfacer works: step by step

1. Shaving: a wide, sharp blade on the underside shaves a wafer-thin layer off the surface. Bumps and grooves disappear.
2. Collecting snow: an auger picks up the resulting snow and carries it into a large tank at the front of the machine.
3. Washing: in a second step, water is sprayed into the deeper grooves, sucked up and filtered to remove dirt.
4. Laying new ice: at the back, a cloth (the "towel") spreads a thin film of warm water evenly over the surface. It freezes into a smooth new layer of ice within a few minutes.

The machine drives in a fixed pattern, usually in overlapping lanes from the outside in. Along the boards, which the machine cannot reach, ice technicians help with edgers and scrapers.

The five assemblies of the ice resurfacer

The 14 components in the diagram can be grouped into five assemblies. Each has its own article with a detailed diagram, explanations of every numbered part, and practical and maintenance notes.

• Assembly 1Drive unitDiesel, gas or electric drive powers movement, hydraulics, augers and brush. Cooling, air supply and power keep it reliable in day-to-day rink operation.
• Assembly 2Water tank systemTanks, pump, filters and valves store the ice water and spread it evenly behind the conditioner. Depending on the model there’s a separate circuit for wash water.
• Assembly 3Cutting and conveying systemThe blade in the conditioner shaves off a thin layer of ice. Horizontal and vertical augers move the shavings into the snow tank.
• Assembly 4Wash and finisher systemWash water loosens dirt from grooves and is sucked back up. Then the cloth, the finisher, lays a thin film of ice water that freezes into the new ice layer.
• Assembly 5Hydraulic and control systemPump, valve block, lines and cylinders move the conditioner, snow tank and attachments. Control levers, display and sensors give the driver control.

Why warm water?

It sounds paradoxical, but it is physics. Warm water

• melts the top layer of ice very slightly and therefore bonds better with it,
• runs into fine grooves before it freezes,
• contains less dissolved air, which makes the ice clearer and firmer.

The exact temperature used depends on the rink and machine. The water is often treated as well so that no minerals cloud the ice.

The invention of the Zamboni

Before the ice resurfacer, preparation took a long time: several helpers pulled planes across the ice, swept up snow and sprayed water from hoses. Frank J. Zamboni, who ran an ice rink in California, spent years developing a machine that does everything in one pass. In 1949 he completed the first version. Since then, ice resurfacers are often colloquially called "Zambonis", even when made by other manufacturers.

Today, ice resurfacers are increasingly electric, because combustion engines release exhaust fumes in enclosed rinks. Many rinks have therefore converted their fleets.

Ice preparation in numbers and routines

• Resurfacing an ice hockey rink usually takes around ten minutes.
• In professional games the machine goes out in every intermission, often two machines at once.
• In figure skating the ice is resurfaced between warm-up groups so that all skaters have similar conditions.
• Curling has its own rules: instead of the machine, the ice is usually scraped by hand and then pebbled.

How the ice is made in the first place is explained in making ice & ice temperature. Who drives the machine and what else the job involves is covered under ice technician.