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#1
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Kuzmin No-waxing thesis
Zach may be too busy to post his response to the Kuzmin paper on steel
scraping being better than waxing. The paper's abstract says that stonegriding and waxing are not as good as an alternative treatment. Kuzmin theorizes that steel scraping is better than waxing because it picks up less dirt. Zach's website has an interesting experiment and commentary cahllenging the Kuzmin thesis. http://www.engineeredtuning.net/Basematerialdemo.htm Peer review reports should be interesting. Edgar |
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#2
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I read all of Kuzmin's thesis. It did inspire me into further reading
(it had bibliogrpahy) but otherwise it's prety weak "reasearch". His arguments are mostly pseudoscientific, for example, the argument on penetration of large molecules of wax versus penetration of small molecules of water. Many reasons can be found why water does not penetrate the base (the most trivial one is that the base is hydriphobic), and, in fact, he does not show what experiments he did to demonstrate that water does not penetrate the base. I wonder what kind of "thesis" the writing is. It could possibly qualify as a junior college research assignment. |
#3
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I've looked through Zach's experiments, too, and they were not
conclusive, either. E.g., I was not convinced the wax did not leak around the seal that he made around the ribbon. Also, it's not clear how thick the ribbons were, and how consistent the thickness of the ribbons is. I think the right question to ask is not if the wax penertrates or not (an all-or-nothing kind of question), but how deep the wax penetrates. A garage type experiment may not address this. Say, the penetration is 1 micron. Then, one will need 0.5 micron thick ribbons to detect penetration by Zach's method. I am not mentionning that roughness of the surface of the ski is probably on the order of 100 microns which makes this all even more complicated. One could dissolve a fluorescent dye in wax, wax the skis, then make a slice of the ski and see the gradient of the fluorescence. But this is not a garage type experiment. |
#4
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I hope I didn't make the claim that I was doing anything like "science"
with my little demonstration. I did my experiment to satisfy my own curiosity on the matter, not to create any indisputable proof. As Andrey has pointed out - there is huge room for error in my "garage type" experiment. That's a very apt description of what I did. For goodness sake, I used electrical tape and printer paper - just what was lying around. I had to make quite a number of attempts to satisfy myself that I wasn't simply getting wax leaking around the edges of the ribbon. I started with just masking tape - and that surely wasn't doing the job. I ended up with a pretty convoluted layering set-up involving sandwiching the edges of the ribbon between two sticky surfaces, and then taping the whole thing down - it reminded me of making roof flashing. Anyway, it's surely not science, but I'm satisfied for my own purposes that I saw wax go through the base material. I realized pretty soon after I started working on skis professionally that there is a lot of room for applied science in the ski preparation, but that trying to be truly "scientific" about the development of new methods, grinds, and treatments is a pandora's box. We don't work in a controlled environment - there are far too many variables at play. The best we can do is to work on an empirical model and test variables as the opportunity arises. In my view Kuzmin's work falls far short of science for several reasons. It is clear that he has started with conclusions (which he started to form, by his report, at the 1995 world championships in Thunder Bay). Then he has selected the variables he wants to test, ignored the rest, and presented his findings as indicative of the need for a paradigm shift. I don't claim to have the ability to explain scientifically the way that skis work. I do, however, have a pretty large head start on the scientists out there who approach this work theoretically without any tactile working knowledge of the materials in use. One micron is what - a hundredth of a hundreth of a mm? In my experience that's at least an order of magnitude smaller than the scale that we're actually working at. The thickness of the ribbon that I tested was 0.02mm as measured on a digital caliper - suggesting that it was in truth someplace between 0.01 and 0.03mm. I'm sure that, measured on the scale of microns, there is a great deal of variability in the thickness of the thing. But experience tells me it doesn't matter too much. If wax is penetrating one micron it might as well not be penetrating at all. We're not talking about molecule-size pores in the actual UHMWPE here - we're talking about sintered structure. Len Johnson has poked a small needle into one of the 'pores' in a ski base, working under a microscope. I've measured weight gain in a ski due to what I assume is wax saturation on the order of 0.7-1.0 grams (using a heatbox). You're not going to get that out of 1 micron penetration, or a film on the ski base, etc. We truly needn't get too carried away here. I've had quite a number of people tell me that I approach the ski prep business very scientifically. And I've had another handful claim that I'm totally unscientific and that I should be running computer models, measuring in microns, etc. I think this is a reflection of a fundamental misunderstanding of, on the one hand, what science is, and on the other hand, what ski preparation is. Zach |
#5
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Zach,
You should ask the ski manufacturers if they can send you some longitudinal slices of base material of different depths of say .1 mm increments ( would have to be a pretty good bandsaw :-) ). Then you could repeat your "garage" experiment to see how far the wax actually can penetrate. I think if you got up to 1 mm you can safely rebuke his thesis. And if Kuzmin's theory is based on flimsy premises, I also wonder how bad or anachronistic his ski testing methodology is? What is the current state of the art for testing glide at the WC level? Chris |
#6
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1mm of wax penetration? Keep dreaming! at risk of sounding
non-scientific (!) I can "feel" how deep the wax goes when I'm metal scraping good base material. I'd say we're talking about several hundredths of a mm - probably not even 0.1mm. In fact, I believe that Toko (and probably other wax companies) have done actual scientific tests to determine how deeply wax saturates the base. I'm sure Ian Harvey would be happy to comment. Or you could try looking up the Toko Tech Manual which is actually a fairly useful document. Plenty of propaganda, but also plenty of good information. There is no state of the art of glide testing on the world cup. Speed traps are used, but everybody recognizes their limitations. The major issue with glide testing on the world cup is that there is very little opportunity for controlled bench-mark testing because most of the process is geared toward race skis. It's a question to coordinating the confluence of lots of different variable, the most important in most cases being ski selection. The skis really have to be skied for feel. Anyway, Kuzmin has used accepted ski testing methodology. No problems there. But by the same token his data is pretty thin, and most people with experience running speed traps would want to see much more. Z |
#7
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Totally agree that there are many holes in Kuzmin's research (I've also
read it). But no one has addressed the most important question to a racer: Is a structured and waxed ski faster than a steel-scraped and unwaxed ski? And does the difference in "fastness" change over the course of a race? Rather than figure out if a ski holds wax, perhaps the test should be to compare sets of skis just after they are waxed/not waxed and after they have been skied in. For example, 1. Multiple glide tests (the before test) of structured/waxed skis and scraped/unwaxed skis are performed, with an average & standard deviation taken. 2.Both sets of skis are skied on. 3. Periodically - every 5km? - the skis are glide tested. The results would show which set of skis was faster or slower at the start (when most racers test glide) AND which skis got faster or slower relative to the other set over time. Simple test - although there are lots of variables that would be difficult to control. Do enough tests, and patterns begin to appear... Mike |
#8
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Believe me Mike - I'm working on it. As you say, it's a relatively
simple test. But you need data. So far the information I have is anecdotal - not enough hard numbers involved. However, the metal scraped skis have been very, very far from competitive. When/if I come up with anything I can call "data" I'll share it, for sure. However, anybody in their right mind would be crazy not to question my findings. Talk about a conflict of interests! Having tested hand structures based on metal scraping as part of my regular testing over the past four or five years I'll say up front that I'm extremely skeptical. When I bought a stonegrinder I had already had plenty of experience working with hand stuctures, and I didn't spend all that money because I thought that grinding MIGHT be faster. I would suggest that anybody who feels that Kuzmin's work is convincing should run their own tests. Competition testing is always the best way to get good information in any case. It can be hard to determine what's "significant" in benchmark testing. Less hard at the mid-point of a marathon. I'm really looking forward to hearing the Birkie stories from the people that do the metal-scrape/no-wax treatment. Naw THAT will be some data! Zach |
#9
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Though I can't find Kuzmin's paper anymore, a couple of notes. First, a
licentiate dissertation is typically a third year graduate paper, the equivalent of a masters thesis in the U.S. It's rare that the quality of research at this level can make it past an "Interesting," and then a specialty library shelf. My experience was that these are more useful for their bibliographies than their substance. It's normal to start with a hypothesis, which is anywhere from a hunch to a conclusion, to be tested (in this case, it's the null hypothesis that's at issue). Fishing expeditions (data mining) without hypotheses are not research, tho many economist's models are built that way. The key is whether the methodology and variables chosen allow for results to come out either way, or are highly stacked toward the a favored conclusion. I have to take a pass here. I do think it's essential to distinguish between two kinds of tests and claims. The first, and most important, was a skiing test: Does adding glide wax to skis vs. some nude condition make a difference in the field? I understand Kuzmin reported a variety of results. The second are any tests or explanations for the causes of those results. In speaking to Kuzmin's claims, I think many comments are tending to overlook the first and jump to the second, i.e., "It can't be true because it doesn't make any sense according to existing theory or my lab experiments..." Gene "Zach Caldwell" wrote: I hope I didn't make the claim that I was doing anything like "science" with my little demonstration. I did my experiment to satisfy my own curiosity on the matter, not to create any indisputable proof. As Andrey has pointed out - there is huge room for error in my "garage type" experiment. That's a very apt description of what I did. For goodness sake, I used electrical tape and printer paper - just what was lying around. I had to make quite a number of attempts to satisfy myself that I wasn't simply getting wax leaking around the edges of the ribbon. I started with just masking tape - and that surely wasn't doing the job. I ended up with a pretty convoluted layering set-up involving sandwiching the edges of the ribbon between two sticky surfaces, and then taping the whole thing down - it reminded me of making roof flashing. Anyway, it's surely not science, but I'm satisfied for my own purposes that I saw wax go through the base material. I realized pretty soon after I started working on skis professionally that there is a lot of room for applied science in the ski preparation, but that trying to be truly "scientific" about the development of new methods, grinds, and treatments is a pandora's box. We don't work in a controlled environment - there are far too many variables at play. The best we can do is to work on an empirical model and test variables as the opportunity arises. In my view Kuzmin's work falls far short of science for several reasons. It is clear that he has started with conclusions (which he started to form, by his report, at the 1995 world championships in Thunder Bay). Then he has selected the variables he wants to test, ignored the rest, and presented his findings as indicative of the need for a paradigm shift. I don't claim to have the ability to explain scientifically the way that skis work. I do, however, have a pretty large head start on the scientists out there who approach this work theoretically without any tactile working knowledge of the materials in use. One micron is what - a hundredth of a hundreth of a mm? In my experience that's at least an order of magnitude smaller than the scale that we're actually working at. The thickness of the ribbon that I tested was 0.02mm as measured on a digital caliper - suggesting that it was in truth someplace between 0.01 and 0.03mm. I'm sure that, measured on the scale of microns, there is a great deal of variability in the thickness of the thing. But experience tells me it doesn't matter too much. If wax is penetrating one micron it might as well not be penetrating at all. We're not talking about molecule-size pores in the actual UHMWPE here - we're talking about sintered structure. Len Johnson has poked a small needle into one of the 'pores' in a ski base, working under a microscope. I've measured weight gain in a ski due to what I assume is wax saturation on the order of 0.7-1.0 grams (using a heatbox). You're not going to get that out of 1 micron penetration, or a film on the ski base, etc. We truly needn't get too carried away here. I've had quite a number of people tell me that I approach the ski prep business very scientifically. And I've had another handful claim that I'm totally unscientific and that I should be running computer models, measuring in microns, etc. I think this is a reflection of a fundamental misunderstanding of, on the one hand, what science is, and on the other hand, what ski preparation is. Zach |
#10
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Hey Zach,
You might consider comparing freshly ground skis with and without wax. That would be limiting the variables to adding wax, and the change in base structure that occurs because of scraping and brushing. You could scrape and brush the unwaxed ski, but you have to make sure to have a new brush and clean the scraper so you don't introduce wax. Another test (hate to keep adding work) would be to test steel scraped skis with and without wax. (Same reasoning as above.) It sounds like you're testing steel scraped without wax vs. ground with wax. I think the other tests would fill in the "holes" (not a scintering pun) of it's really the wax making the difference or the ski base structure. I started reading the thesis and it already seems like an editorial rather than a scientific paper. I think the wax companies are probably correct with ideas like wax penetration and that waxing a ski prevents abrasion, but probably don't really know why. I don't think there's any reason to worry about "oxidation" of a ski base, but I'll read further and comment later. Jay |
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