mythosgrl Posted October 17, 2008 Posted October 17, 2008 For all those chalk haters out there, this is for you: http://www.ncbi.nlm.nih.gov/pubmed/11411778?ordinalpos=9&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum Coating (chalk vs no chalk), dampness (water vs no water) and rock (sandstone, granite and slate) were manipulated. The results showed that chalk decreased the coefficient of friction. The counter-intuitive effect of chalk appears to be caused by two independent factors. Magnesium carbonate dries the skin, decreasing its compliance and hence reducing the coefficient of friction. Secondly, magnesium carbonate creates a slippery granular layer. We conclude that, to improve the coefficient of friction in rock climbing, an effort should be made to remove all particles of chalk; alternative methods for drying the fingers are preferable. I am not arguing yay or nay for chalk (there are past threads for that if you want it), but I just thought it was interesting. Quote
rob Posted October 17, 2008 Posted October 17, 2008 Finally, water had no significant effect on the coefficient of friction. tell that to someone who's greased out of a crack on a hot day. And, why would "alternate methods for drying the fingers" be preferable, if water has "no significant effect on friction?" Quote
Rad Posted October 17, 2008 Posted October 17, 2008 Finally, water had no significant effect on the coefficient of friction. And, why would "alternate methods for drying the fingers" be preferable, if water has "no significant effect on friction?" Oil (aka grease) is the problem, not water. Perhaps that's why liquid chalk has a lot of isopropanol (rubbing alcohol). Quote
rob Posted October 17, 2008 Posted October 17, 2008 Hmm, that kinda makes sense I guess, but I thought sweat was mostly water. However, if sweat is oily, then I wonder: chalk may lower the coefficient of friction, but does it lower it more than oily sweat does? It would seem not, since chalking seems to help. However, it doesn't seem like the study added a control for oil -- just water. Quote
tomtom Posted October 17, 2008 Posted October 17, 2008 Replace your Astroglide bottle with your chalk bag next time and let us know how it goes. Quote
Couloir Posted October 17, 2008 Posted October 17, 2008 Astroglide is very expensive. But a little goes a long way! Quote
rob Posted October 17, 2008 Posted October 17, 2008 Replace your Astroglide bottle with your chalk bag next time and let us know how it goes. Quote
marc_leclerc Posted October 17, 2008 Posted October 17, 2008 I find water doesn't decrease friction on its own. If there is a bit of algea or other particles on the rock the water ir running on then you get slippery rock. Also, I know chalk decreases friction. Thats why we have little brushes to brush chalk off holds. To dry your hands you should dip in your chalk bag and then blow/clap to get all that excess chalk off your hands. Quote
Choada_Boy Posted October 17, 2008 Posted October 17, 2008 To increase friction, I increase the particle size of the chalk and hold a large rock in each hand. Quote
Cairns Posted October 17, 2008 Posted October 17, 2008 For all those chalk haters out there, this is for you: http://www.ncbi.nlm.nih.gov/pubmed/11411778?ordinalpos=9&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum Coating (chalk vs no chalk), dampness (water vs no water) and rock (sandstone, granite and slate) were manipulated. The results showed that chalk decreased the coefficient of friction. The counter-intuitive effect of chalk appears to be caused by two independent factors. Magnesium carbonate dries the skin, decreasing its compliance and hence reducing the coefficient of friction. Secondly, magnesium carbonate creates a slippery granular layer. We conclude that, to improve the coefficient of friction in rock climbing, an effort should be made to remove all particles of chalk; alternative methods for drying the fingers are preferable. I am not arguing yay or nay for chalk (there are past threads for that if you want it), but I just thought it was interesting. Seems to be a small study done 7 years ago. Probably doesn't model V15 or 5.15 very well. Probably climbers would've noticed before now. J. Sports Sci. not so hard to get published in - check Citation Index to see if this study had any connection to anything It's already known that shoe rubber on bare rock isn't way more slippery when wet; skin could be the same deal BUT mixing chalk with water, e.g. sweat, could lead to a variety of possibly contradictory effects on friction, depending on the proportions, and there are other substances in the mix which could be sources of variation, such as psychology, spiritual attunement to the rock (is that possible with the pebbles used in the study?), and shorts over polypro. Quote
bstach Posted October 17, 2008 Posted October 17, 2008 If water doesn't affect friction, then the guy who has been selling me car tires has been lying for years. Quote
bstach Posted October 17, 2008 Posted October 17, 2008 No, but they are designed to shed water. Quote
G-spotter Posted October 17, 2008 Posted October 17, 2008 So are ducks, but when I put my car on them it doesn't go very fast. Quote
layton Posted October 17, 2008 Posted October 17, 2008 Seems to be a small study done 7 years ago. Probably climbers would've noticed before now. J. Sports Sci. not so hard to get published in - check Citation Index to see if this study had any connection to anything It's already known that shoe rubber on bare rock isn't way more slippery when wet; skin could be the same deal What he said. What's more slippery - chalk or oil? Are there better alternatives while climbing? Sawdust? Charcoal? Silica powder? Quote
CollinWoods Posted October 18, 2008 Posted October 18, 2008 I will keep on using chalk unless i go to that place in germany form the reel rock tour, then i would also be using "knot cams" Quote
marc_leclerc Posted October 18, 2008 Posted October 18, 2008 If water doesn't affect friction, then the guy who has been selling me car tires has been lying for years. Water mixes with oil and shit on the road... thats why it is slippery Quote
A2THEK Posted October 18, 2008 Posted October 18, 2008 a small pouch of MEK, acetone or lacquer thinner would negate the chalk issue completely, if it's the oil that's the problem, plus all the compulsive bag-dippers would eventually die off, leaving the crags full of chalk free & less polished holds for the ultra traditionalist coalition. If you wanna try sawdust, I have tons, all types, u-haul. Quote
G-spotter Posted October 18, 2008 Posted October 18, 2008 Water mixes with oil basic science fail? Quote
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