CURLING 2000
Discussion about early Pebble Wear.
Written Dec.24, 2000 no curling today. Below: Beagle rules the woodlot.
Recommendation to the CCA and World Curling organizations to allow a change of brushes during a game.
Since this is to be an interactive discussion, your views are important and necessary, please click on my e-mail address and send me your best thoughts@curling2000@telusplanet.net.
    First off, I think a nylon covered brush has advantages in the first 2 ends when the sheet has not been clipped/dragged AND when there is a very unusual buildup of frost as in coastal areas when the outside air is very humid above freezing and or it is raining. 
    After the first ends, there is no doubt in my mind that a soft face brush -- sheepskin is the head to use. The sheepskin holds frost to be used as a "lapping" compound and NOT as sandpaper --hard nylon. The frost carried in the "fuzzy" face does the same job you do when polishing your car. You put a mild abrasive like toothpaste on a SOFT rag to polish the paint. You will take off only the light oxidation while not penetrating and removing the paint. 
    If you want to remove paint, you use hard backed sandpaper, right?
This view asks the question. Why not be able to use different brushes during a game? A CCA challenge to the rules? Let's give brushing the importance it deserves. After all, brushing is the exercise part of the game AND it makes the brushers interactive and very important to the TEAM -- a team sport.

Why does pebble wear out too soon?
  Basic curling scenario:
   FACTORS affecting pebble stability.
    1.Ice temperature.
    2. Brushes being used.
    3. Sliders being used.
    4. Rock running surface configuration.
    5. Type and amount of pebble applied.

1. Ice temperature:
         Ice surface temperatures can vary from 18 degrees F to 32 degrees F while the subsurface base of sand or concrete can often range from 16 degrees F to 28 degrees F.. Of course the brine can be allowed to increase above freezing to accommodate a melt down.
    We know that the colder the ice, the harder the ice. So with pebble present, colder ice will cause the pebble to be harder and generally you would assume it to last longer. EXCEPT there is a limiting "cold" factor in which the ice becomes so brittle it is no longer "tough/ flexible" and large, hard, chunks of pebble can be removed by sliders, brushing, and rocks which radically damages pebble and changes curl. The quite evident drawback of cold ice is -- it is always slower ice considering all other ice making factors being the same.
    The ice technician must adjust the surface ice temperature to gain the "happy" medium of tough pebble with the fastest possible ice speed based solely on ice temperature considerations. He "adjusts" ice surface temperatures by changing the brine in/out temperature and maybe flow rate if he is lucky enough to have such a sophisticated system and by changing the air temperature. In TV events, the air temperature is affected by extra "TV" lights, convection, AND the sheet surface temperature by radiation. 
    If large numbers of people are coming and going to the curling area environment, then add in the humidity factor and temperature factor of changing air from outside and 100-200ml. of water vapor exhaled/perspired per adult size person per hour. Normally the small increase in "available" water from curlers alone is negligible in increasing the actual water held in the rink air. It is the exchange of air from "outside" the ice area and particularly when the outside air is above freezing, i.e., coastal areas, that there can be a major humidity problem. 
    The location of downdraft fans and horizontal furnace fans can affect localized surface ice temperatures as well as overhead "high" heat source lighting. Most clubs have gone to low radiation lighting with light deflecting shields which improves power economy and lowers the radiation sheet surface heating effect.
    In most club curling situations, the first draw will encounter a cold ice surface temperature AND cold air temperature because the ice technician usually shows up minutes before the draw and raises the furnace settings. After the last draw, the furnaces are often set lower or shut off to conserve gas energy and electrical power energy. Every BTU put in by the furnaces must be removed by the more expensive electrical energy consumed by the refrigeration compressors. So the more you run the furnaces, you can more than double the power consumption. Needless to say, the ice speed and curl can change radically as the air/ice surface temperature changes during a game.
       

2. Brushes in use.
        Currently there are only two major brush surface types in use. The Hammer Co. offers sheepskin and "carpet" as an alternative brush head cover.
            A. The nylon covered brush in brown or blue.
            B. The hair brush of either pig or horse hair, horse hair being softer and more flexible than pig hair.
    My recent investigations, aided by several e-mails from interested curlers and ice technicians, indicate a bias toward the "I think" evidence that the "nylon" covered brushes wear out pebble faster than the "hair" brush.
    Since less than 1 in a thousand curlers use wool/sheepskin and or carpet brushes, we have little data other than my own tests on my wool covered brush to go by to infer these "soft" face brushes do or do not cause early pebble top failure. I can assure you that the wool/sheepskin cover is superior -- you can control the rock and extend travel.
    The only comparative studies that I have done -- on an "I think" basis is the review of TV curling tapes in which it seems the women experience less "fudging/pebble top wear" when using nylon brushes than men when using nylon covered brushes. Having curled hundreds of games with seniors in which there was pebble left standing after an 8 end game and then practiced on the same sheets afterward makes me draw the same conclusion.
    If you don't push down hard, you don't wear out the pebble as fast. Men curlers, on TV and  home club games, regularly "seem to" brush the pebble flat causing late end flattening/fudging/slowing. The obvious correlation is, they push down harder and brush with more cycles while also brushing more than the rock's running surface and probably do more damage to pebble tops.
    An obvious test situation follows assuming the relative same amount of brushing is done on every sheet:
AND my assumption is correct that ladies don't brush as hard and as fast.
 Someone could time the total brushing time for each sheet (2 brushers at all times).
        Place men on sheet 1 with nylon brushes and men on sheet 2 with hair brushes and compare pebble height and condition before and after a 10 end game.

        Place ladies on sheet 3 with nylon brushes and ladies on sheet 4 using hair brushes and compare pebble condition after 10 ends.
    Then compare the pebble condition men vs. women using the same nylon or hair brushes.
        My pretest conclusion estimate of pebble condition would be rated as follows:
        Ladies with hair brushes cause least damage to pebble.
        Men with hair brushes and ladies with nylon a close second and,
        men with nylon brushes wearing the pebble the most.
    What do you think? E-mail me.

3. Sliders being used.
    The only "evidence" I can offer from personal experience is I hear and feel crunching of pebble under my slider in the first 2 ends when the ice has not been clipped or dragged.

4. Rock's running surface configuration.
    Here again, I can only relate experiences in which clubs with 3 feet plus of curl and with "sharp edged" rocks -- high incidence angle and high relief angle to and from the running surface have difficulty maintaining pebble when the ice is warm 926-30) and or they are pebbling with a weed sprayer. Normally for an 8 end game when the surface temperature is maintained at or below 26 degrees F (the subsurface base is 22-24F), and a gravity pebbler was used, the pebble lasts 8 ends. I don't play many 10 end games.

5.Type and amount of pebble applied.
    In my view, the gravity pebbler is the only device to be used to apply pebble. The backpack model provides uniform pressure with ease of carrying.
I have reviewed pebbling in on my other webs and will not repeat that data here. To attain speed with curl, suffice it to say, "pebbling is very complicated."
In summary: Large pebble (big tops and not splats) properly spaced has the best chance of holding up to 10 ends of brushing and rock travel.
And now for fun, The beagle and the hare.
BUT WAITE!!!
Hey, backyard philosophers! Are we going to read a simple poem or a metaphor about life itself?
You be the judge. The words are simple, but is there more?

The Simple Life


Dog's ears flop, gyration and wind
Rabbit hops wildly, indecision

                                                              Dog's tail wags in rhythm, scent strength in tracks
                                                                  Rabbit's white cottontail flips in the sun

                                                              Dog pursues head down without understanding
                                                                  Rabbit eludes by instinct

                                                              Dog pursues relentless, ah-oow, ah-oow
                                                                  Rabbit tires, breathing fast, must evade

                                                              Dog breathes heavy, stays on scent track
                                                                  Rabbit's heart small but fear is large

                                                              Dog's incessant howling, ah-oow, ah-oow
                                                                  Rabbit silent in its escape

                                                              Dog's experience, master hunter, ah-oow, ah-oow
                                                                  Rabbit's fear, millenniums' surviving teacher

                                                              Dog's nose to the ground inhaling scent
                                                                  Rabbit's refuge, a hole in the ground

                                                              Dog's short legs, no sprinter
                                                                  Rabbit's genes, the plan for escape

                                                              Dog knows only instinct to pursue
                                                                  Rabbit knows instinct to escape

                                                              Dog happy in the chase
                                                                  Rabbit is fearful to elude

                                                              Dog is Beagle
                                                                  Rabbit is Cottontail.

                                                               HAPPY HOLIDAYS
                                                                              and
                                                                        Good Curling  
                                                                  The Curling Doctor

                I can help ANY curler in the world, pro or not, who truly desires help. E-mail me -- it's free.
curling2000@telusplanet.net