There are two things that have to work together to make curling work, the stones and the ice. There are two ways of going about it, controlling the stones and controlling the ice. If the stones remain constant, the ice remains the only variable, and if that can be controlled then the game is down to the players and their skills. If the stones do not remain constant there are two variables, and everyone tries to blame one or the other when things go wrong. It used to be the ice that was blamed, never mind the facts, but now it is becoming the stones. Why?

There are two kinds of curling stone to note here: naturally matured stones, which will after a few months have a smooth and consistent running band, and artificially matured stones, which will have been prepared by the stone makers to resemble whatever they deem the ideal to be. In cold countries of -30C OT and say 2C AT inside, the IST could be as cold as -5C with no means of warming it up. On such a surface the NM stones will not curl much, while the AM stones will have been prepared with a rougher running band to create sufficient friction to curl. In warmer countries with an OT of 10C and an AT of 7C, the IST can be as warm as -3.2C. On such a surface the NM stones will curl well and will be extremely consistent, provided the IST remains constant -- usually the IST will be maintained at -3.8C to provide the required consistent temperature. The AM stones will however curl far too much, as much as 12ft, on the same warm surface.

In large curling rinks (more than four sheets) the control of the parameters become much more difficult, and the workload to maintain the ice surface becomes beyond the average technician. In order to save time and to overcome the problems of control technicians run the ice colder, usually colder than -4.5C. In effect, they are creating the same conditions as those in colder countries, and are then forced to use AM stones to create sufficient curl. To go one better, they buy a pack of sanding paper and slide the stones over the paper to roughen the running bands, resulting in the dives sometimes seen when they overdo it. Many technicians have ruined their stones by doing this. More cautious ice techs send their stones to Kays to be refurbished, with a more consistent finish and more predictable behaviour, and Kays have become very good at this. So we enter the realm of "competition" stones, prepared by Kays for cold ice in arenas, and "club" stones, which will behave themselves on warmer ice.

There is however one problem: the rough texture of AM stones does not last very long. After a month or so the stones become smoother and gradually straighter, and after another few months they become NM stones. Instead of using the parameters to control the ice, the technician sends the stones back to Kays for another refurb. But the stones also have two sides, and these can be prepared for "club" one side and "competition" the other, and if a technician saves the comp side for serious comps the curlers will be happy. This side will last for a few competitions and then gradually become smoother, while the club side will be whatever it is allowed to become.

The question has to be asked: which is the better way. Arena specialists will study the competition stones well in advance before making the ice, and will have data from other venues to use. That is why there are sets of WCF stones travelling the world in boxes. Cold rinks (and usually large ones) do not have the luxury, they have to contend with club curling every day and two sets of stones will be too much of a luxury. I have every sympathy with these guys, but I have also seen arena ice with NM stones that work extremely well, and probably better. When working with NM stones there is a constant, because these stones do not change their behaviour very quickly (I know of NM stones that have been in use for twenty years, with no refurbishment!). They are easy to match into pairs and sets, and they make for wonderful curling. With such a constant it becomes possible to fine-tune the ice to such an extent that the ice becomes a constant. To me it is quite clear: NM stones and warmer ice is the right way to go. It is easier, better, cheaper and extremely controllable.

The Circle was designed to create the right conditions for curling, using either AM or NM stones. It was designed as a four sheeter (but five can work) to avoid the problems of larger rinks and the high running costs. It does not surprise me that the RCCC and MHG want to build a six-sheet NCA, they know very little about stones and ice and are easily persuaded by technicians who tell them what they want to hear. It does not surprise me that these technicians work in large rinks and often do not produce the best conditions, because the problems are enormous. So why build an NCA that is too big, too difficult to maintain and too expensive to run? They all want the glory of competitions, never mind the club curlers who pay the bills. If any of them had any knowledge or sense, they would be building the Circle and avoid the problems, especially those caused by cold temperatures and artificially matured stones. It is not necessary to go that way, and this is regularly proved when a large rink cannot provide excellent conditions not only for competitions, but on a regular daily basis.

Hey, talking about scratching the surface! Keep going John, but don't scratch too hard. This stuff is over the head, like.....
One thing though. Is it possible to match scratched stones?

Yes, but it depends how well they should be matched. The parabolic curve of an AM stone is less predictable than that of a NM stone, so it will take some time just for that. The speed is less of a problem, but because the AM stones are more aggressive on the pebble they will wear the pebble more, unlike the NM stones, and with the latter you could probably match all 16 stones on a sheet within ten minutes. As you'll know, it is not a bright idea to match too many stones on the same ice, and even then the ice has to be very good! Add to this the problem that the AM stones will lose their characteristics week by week, it would be best to match them every week, but what idiot is going to bother doing that?

Give me NM stones every time.....

Hey, John. If I've got it right, you're saying the new NCA will have all the same problems as the other big rinks, because of size and stones? I mean, aren't they really just creating a new place and moving all the same problems to it from other rinks? Do these people have brains??

I know that climate conditions are different in Canada, but interestingly, of the 31 rinks that I played in over there, all provided excellent ice.  The rinks varied in size from a two-sheeter in Lennoxville to an eight-sheeter in Toronto (part of a multi-sport club).

We were struck by the consistency of weight across the Provinces.  The ice was obviously a major topic of conversation after our games; we were told that the conditions we were experiencing were the norm and had not been laid on specially.

All of this is anecdotal, I know, but nonetheless interesting to share.

I was on the east coast tour, so did not go further west that Ontario.