One of the most important aspects of curling is the playing surface. Simply put, making curling ice is an arduous challenge. You can’t just take out the garden hose and slosh it around. It’s an exercise of precision that demands patience and a skillful hand.
To learn more about this exact science, I spoke with experienced ice-maker Jim Ridenour of the Schenectady Curling Club. Jim is considered by many to be an expert in his field. He’s been called upon to make the ice for the 2002 Salt Lake Winter Olympics, various Mens, Womens and Seniors World Curling Championships, as well as other premier curling events. He’s traveled the world to hone his ice making skills. Last week, he sat down with me here in Schenectady.
R: Thanks for joining me, Jim.
J: Sé do bheatha, laddy.
R: You said what now?
J: It’s Scottish Gaelic. It means, ‘you’re welcome, son.’
R: Ah, right. That’s appropriate because curling is originally a Scottish sport.
R: So... when most people see curling ice for the first time, they assume it’s just frozen water. Like hockey ice. How is curling ice different than say... the ice in my driveway?
J: First of all, the ice in your driveway conforms to the shape of the surface. It has slopes, and dips, etc. Ideally, curling ice is level. The ice in your driveway also has lots of stuff in it. Salt, and dirt, and other elements. Curling ice is pure.
R: Explain pure.
J: We purify the water here at the club with a water treatment system. It takes dissolved ions out of the water. Tap water has too many chemicals in it. Using un-purified water would make for poor curling.
R: I can curl poorly even on pure ice, my friend.
J: Ha, well, the ice can be a big factor, from what’s in it, to the way it’s pebbled.
R: Most non-curlers probably don’t know what “pebbled” means.
J: Before each game, we sprinkle water on top of the ice. The little droplets freeze, and leave a bumpy, “pebbled” surface. In this modern game of curling, you have to throw the rock a long way. On flat ice, surface area friction would prevent the rock from traveling very far. The frozen drops of water reduce the surface area in contact with stone, thus allowing the rock to travel further on the ice.
R: I heard the pebbled surface is what actually allows the rock to curl. Are those little droplets responsible for the curved path the rock takes on the ice?
J: Well, there’s an ongoing debate about what actually makes the stone curl. PhDs continue to argue over the facts. When they talk about the curling of the rock, many factors must be examined. Things like frictional interactions and differential velocity vectors come into play.
R: That sounds complicated.
J: That’s why I just make the ice. In terms of the physics behind curling, I’ll take a back seat until they figure it all out.
R: How long does it take to create or install ice like that?
J: At our club, installation starts in April. We take out the previous season's ice. We melt it, wash the paint out, etc. We do this in a way that leaves sand field as clean and as level as possible for next season.
R: So, underneath all that ice is a sand base?
J: Yes, the Schenectady Club has a sand base. Other clubs have concrete. There are pipes running through that base in which we circulate a brine-based coolant. That’s what allows us to freeze the ice.
R: What about actually putting the ice in?
J: To actually make the ice for the season, it usually takes about 2 weeks of hard work. We flood the base, and run coolant through the pipes. Once the ice is thick enough, we’ll paint it, and continue to flood more water on top of that until it’s ready.
R: Once the ice is in for the season, is there a lot of maintenance?
J: There is a lot of maintenance. Many factors will contribute to the ice changing. Humidity levels, temperatures, air flow... they all play a part. During the season, I’m constantly looking for irregularities in the surface. If needed, I’ll do a leveling flood. Sublimation can also be a problem.
J: Above the ice, you have an air mass with low humidity. Even though the ice is frozen, it’s still water. So often times it will evaporate directly into the air. The rate at which this happens is different in various parts of the ice sheet, based on how close it is to a cooling pipe.
R: And a leveling flood will fix that?
J: It can, but it gets complicated. If you have surface highs and lows on the ice sheet, and flood it with water, the water will seek to level itself. More water will flow to where the ice is lower on the sheet, and less water will flow to the high points.
R: That doesn’t sound too complicated.
J: Well, you also have to consider that as water freezes, it expands about 10 percent by volume. So, the low areas where more water flows will expand to a greater volume than the high points with less water. Once it’s frozen, your lows will become your highs, and your highs become your lows.
R: So it’s backwards.
J: Aye. Then I have to go out there, and closely evaluate the entire sheet. I find out what exactly happened to the ice levels, and where. I’ll do a scrape or two and attempt to level it. But it’s not an easy task, and flooding is not a simple fix.
R: I’m getting dizzy. That sounds like a lot of work. But if that’s what it takes to make quality ice...
J: The quality of ice is all about how much effort one puts into preparation. If your folks come in to town for holidays, you either have to clean the house all at once, or a little at a time. I try to stay on top of it a little at a time, so that it never gets out of hand.
R: Are you the only only one who evaluates the ice?
J: All members at the club are constantly evaluating the ice. Each member has a different perspective. With so many viewpoints being shared, not everyone’s analysis will be the same. But it’s important that a head ice-maker is willing to listen to everyone’s opinion.
R: So, over the course of the season the ice will change due to many factors. But what about over the course of one game? I know the ice changes while we’re playing on it. What’s going on out there?
J: The pebble layer is abraded by stones and brooms. As the players throw and sweep, the top layer wears away. People play, they sweat, they fall down... all these things can create runs, or grooves that need to be fixed.
R: How many hours a week do you work on the ice?
J: Usually 10 hours during the 5-day work week. If we have a tournament on the weekend, I usually spend close to 40 hours here on Saturday and Sunday.
R: Wow. That’s a lot of work for just one man.
J: Well we have an ice committee here, with close to 40 members. They can each do various aspects of ice maintenance and preparation.
R: I don’t see too many Olympic-caliber ice makers walking around these days. Is it rare that a club will have someone as experienced as you to work on their ice?
J: It’s rare, but it’s growing in the States. I’ve been fortunate enough to go to a lot of places and learn about ice making. I’ve taken advantage of the many opportunities presented to me.
R: Well, we’re fortunate to have such a dedicated ice maker at our club. Is it true you have a vanity license plate on your car the reads, ‘ice maker?’
R: You’re a rare breed, Jimbo.
J: Awa' n bile yer heid, laddy.
R: I’m not even going to ask what that means.
J: You probably shouldn’t.