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Ski tunning, know how

Ski tunning, that is, the sharpening of the edges and the waxing of the sliding surface, is described in the Net quite well, perhaps even too well. A lot of stages. Perhaps, too much. Sometimes there is an impression that it is better to entrust this to a specialist. Or as it quite difficult, sharpen and wax the skis not often, a couple of times a season. My approach to the topic is not constant, so I’ll write how I act this (2018) season. Just say that it is not exactly correspond to how it usually done, so do not think my approach is the only right 🙂

Edge sharpening

When riding, the edges are dull, and when sharpening, they are grinded off. This determines the service life of the skis. Therefore, we have to look for a compromise, how to keep the edge sharp, but take less shavings 🙂

Many years ago I’ve derived for myself such a rule:


Moral damage from riding on blunt edges is much greater than the financial loss from edges sharpening


Nevertheless, following to this rule is not very simple, since it is difficult to determine the required degree of sharpness of the edge.




What is a sharp edge?

Judging by the opinion of colleagues from the club, the definition of sharpness can be quite different. Some warn, when you touch their skis: “Carefully, you can cut yourself.” And some rides while “skis is held” and sharpen right in the field. My degree of sharpness was somewhere in the middle, determined visually by the absence of a facet, that is, sides of edge from sidewall and from the base should have a clear boundary. Approximately this is sharpness of new skis. Now I came to the conclusion that the edge still must be sharper than in the absence of a faset at the corder, and check the sharpness of the edge “by the finger”. This is certainly a subjective feeling, but in the Network found a fairly clear criterion.
You need to take a ballpoint pen or a felt-tip pen, or another something made of not very solid plastic. Then you need to hold it across the edge, that is, at an angle of 45 degrees to each face. Without special pressure, chips from the plastic must be removing. Such sharpness of the edge should be “remembered” with a finger. You need to touch a finger across the edge, but carefully of course 🙂

Sharpening from the side of base

From the side of the sliding surface the edge could be tunned, or it is possible not to tune, the factory sharpening usually specifies the required angle. In this season, I sharpen from the base by half a degree with the help of a special device (in the picture above – the second from the left), with a small file (that is, not very rough). While, for example, last season I did not sharpen from the base, only sometimes went through with ceramic files. In any case sharpening from the side of the base is not regular, only when I do not like the condition of the edge.




Normal edge sharpening (from side)

Before each sharpening, it is necessary to go with a special knife to remove the a small part of sidewall, more precisely the plastic on the sidewall of the ski adjacent to the edge and slightly grab the aluminum shavings from the plate that is over the edge.
In other words, you need to release the surface of the edge, so that the file does not catch anything except the edge. If a file with large milled teeth, then it is not necessary. But in this note I analyze how to tune the edges that are not in a failed state. Therefore, it is assumed that a fine toothing file is used. Such a file badly works with plastic and aluminum and if meet it then stop to “cut” the edge. This is pretty clearly felt, then you need to go in this place with a knife to remove the sidewall plastics and aluminum.

I snap the file at one end with a spring clamp to the angle guide (angle is 87 degrees).
The second end I press to the angle with my hand when I press the file to the edge. The movement of the hand is strictly to itself (if you sharpen with your right hand).
This is due to the fact that the tooth of all files for ski sharpenng are made “to one side” and with this movement the chips and sawdust are removed to the sidewall side  and not to gliding surface of the ski. On the slide, of course, it still gets something, but it is not much and then it is easily removed. You can glue a paint tape on the gliding, but I do not, laziness.

You need to press more or less depend on the sharpness the file. So that the file “cut”. If file stop cutting, just move it at little inside the guide. Unfortunately, the properties of the new file are lost very quickly, after sharpening one skis, so basically you have to deal with more ir less dull file. The criterion of the final dullness of the file I have not yet worked out 🙂

So, you sharpen by the movement to yourself and check “on the finger” the sharpness of the edge. It is quite simple, simpler than visually controlling the withdrawal of the facet.




Remove burrs and polishing

After sharpening the edge from the side, file left burrs that “look” down. The Network is strongly recommended to clean them with ceramic or diamond files. In addition, it is said that it is desirable to polish the edges with ceramic or diamond files of minimal roughness, then the ski will go faster. In general, not to write much words, from the set of ceramic and diamond files I left only one, the most rude, by which sometimes go on both sides of the edge by hand (without guide), if it is enough to make edge sufficiently sharp for this time.

Regarding burr after file. I remove it by the easy passage of the “gummy stone” from the side of the base. And you can not remove, after a fine toothing file burrs are insignificant.

You do not need to polish the edges. The combined experience of colleagues and my own say that on the ice is better held not polished, but “rough” edges from the file. And if not ice, then the rough edges are not so slow, so that it was noticeable 🙂

It should also be noted that on the new ski edges are not polished, but rather with incisions. Opinion about them among the servicemen is different, but ordinary skiers do not hurry up to retune new skis.




Rounding edges on tip and tail

The edges are dulled unevenly along the length of the skis: in the middle there are worn more, on tips and tails less. That is, mainly the middle part of the ski works. It is difficult to say whether this implies that the edges can be sharpened unevenly, in the middle sharper, on tips and tails are dumber. But according to my observations, the ski, which is sharp along the entire length, sometimes “bites”. Sometimes the tip suddenly clings, and the tip of inner ski, which is especially unpleasant. And sometimes “does not let go” the tail. Usually this happens on a bad surface, that is, the tip clings not for the “correct trajectory”, but for some unevenness. This became especially noticeable this season, when my norm of sharpness of the edges increased, that is, the edges became sharper than before.

Hence the conclusion, how to round (dull the edges) on the tips and tails. They certainly should not be round, but just have to be “as before”, not so razor sharp “on the finger.” This is done with a gummy stone, you need to go with a little pressure 45 degrees across the edge, making a smooth transition of “razor” sharpness from the working part of the edge.

How to determine the point from which the end of the ski edge should be smoothed? It is absolutely certain that one can not support the sharpness outside the “working part of the edge”, as written in the note: Ski sidecut radius and radius of a circle. I will remind you pictures from this note.

Illustration of mistake in calculating the radius of ski at the widest points

Red color indicates the working part of the edge, and the green curve that matches the side cutout of the tip. This (green) part will not cut the snow in a turn, but it can cling to any irregularities. Therefore, you can safely do it dumber. On a real skis (Atomic FIS SL 165 cm), the working part of the sidecut looks like this:

Working area at tip of skiWorking area at tail of ski

 

By green here is “covered” the working part of the edge, with which the ski cuts the slope. Red parts that are not covered in green can be not sharped without losing the grasp of the ski.

In figures (for slalom ski Atomic FIS SL 165 cm), the working part of the edge is located between the points: 2 cm to the center from the widest part of the ski on the tail and 4 cm to the center from the widest part on the tip (shovel). Outside the working part, you can safely dull the edges with a gummy stone (with a smooth transition to the cutting part of the ski). Checked it on the slope. Indeed, on a bad surface (frost-bitten after a rain of snow with lumps), the ski does not cling. You can push a ski across the slope much more confidently (on my level, of course :)).




Waxing sliding surface

The “classic” waxing of base in my opinion looks quite ridiculous. First, the surface is generously dripped with molten paraffin, then the paraffin is smoothed out with iron. And then completely scraped off by the plastic scraber. And what remains – is cleaned more with a rigid brush to “open the structure.” In general, almost all the paraffin goes into the trash can.

Only an insignificant part of the paraffin goes into the pores of the polyethylene of sliding surface and does its job on the snow. I’m not capable of such feats before every skiing. But I always prepare skis in such manner before competitions, although I’m also not so sure that it gives something. Right before the start, I still go on a base with an accelerator tablet, which provides a noticeable glide for one descent. And how much improved the sliding the boring procedure of melting-scrabling-cleaning is difficult to notice 🙂

Nevertheless, the polyethylene on the sliding surface is porous and the pores must be saturated with paraffin. Otherwise, it’s bad for him 🙂

For the fast saturation of polyethylene with paraffin, there is a beautiful solution that can be used before every skiing. In shops in a department for a barbecueis sale the liquid for ignition sated with paraffins. The authorship of the idea of using this liquid for skis belongs to Mikhail Yarlevov. Mikhail began using this liquid to improve the glide on the specific coating of the Snej.com (pipe for summer indoor skiing).

Mikhail Yarlevov. Photo: Sergey Komlev

Cover in Snezhkome made of pounded ice (not snow, that is), with a film of diesel fuel and soot from the exhaust gases of the ratrack (the inevitable consequence of a indoor skiing). Ordinary ski paraffins there simply do not work, because they “attract” soot. Better not to wax ski at all.

Michael found that if you wipe the skis by the liquid for ignition (mainly to remove dirt and soot), then slip is better than just a pure scrabed ski.

Polina Nechaeva, June 2017

It is interesting that this summer the idea of using liquid paraffins for sports skiing was brought from Italy by Polina Nechaeva.

Her familiar servisman said that now the paraffin for skiing does not need to be molted. He gave the jar a liquid paraffin and a natural sheep hair. It is necessary to smear skis with this liquid paraffin, and then rub it with sheep hair.

Approximately so now I do. According to technology from Polina, but with the liquid “from Mikhail”. I rub the skis with a cloth moistened with a liquid for ignition (which is good – the liquid does not stink, and paraffins there should be harmless). For half an hour, the liquid is partially absorbed, partially dry. Then I rub it with a woolen cloth. And a cork, just in case. For the experiment, I scraped a little bit of red Swix into the liquid (which is for plus temperature), but surprisingly, it does not dissolve very much there, more precisely it dissolved in two weeks in the form of a white liquid that settled on the bottom (shake before use!).

So this season I saturate the base before every skiing. But before the competition I do the old-fashioned way, until there is no certainty that paraffins from the liquid for ignition give me a best glide.

However, variants are possible. Quite good sliding is obtained if you “rub” the ski with paraffin Swix for the desired temperature, then wipe with a cloth with a liquid for ignition, and then, when this “pie” dry wipe with a woolen cloth and walk with a brass brush to open the structure.
Well, a woolen cloth as it turned out can be replaced with a roll of kitchen towel from non-woven fabric. Wipe until the surface is noticeably slippery. In general, variants are possible 🙂




Additions

Closer to the end of the season 2018, I had to re-think about two aspects: the side angle of the edge sharpening and the sharpness of the edges on the tips and tails. Biefly say, the final week of the season (twice on the slalom course and three times in free skiing) I rode on the sharpening angle of 86 degrees and with the “razor” edge sharpness to the middle of the bend of the ski on the tip. I’m not sure if this is correct, but I write how went to this.

It so happened that I have got “warming-up” skis (from Sergei Akhmanov), exactly the same as my skis, but with a little amount of edges.
Ogasaka Triun SL 2015

On the “warming-up” skis I installed the slalom course and rode on gummies (warming-up course installed with short flexible poles). And on the main skis rode on slalom course. It turned out that the skis are not exactly the same, especially noticeable on the first run after the pair change. And, “warming-up” skis I liked more, more “toothy” and easier to enter the turn. Of course, maybe the skis are slightly different, but firstly need to do the same manner of sharpening (both pairs equally sharp). On the “warming-up” skis edge side angle is 86 degrees, and the razor sharpness continues to the “middle of the bend” in the front of ski. I talked with colleagues, it turned out that almost all sharpen to 86 degrees. About tips, in different ways. Some just do not sharpen tips, gently reducing the sharpness to the widest part (so the file cuts “himself”), and some continue the sharpness to the bend, as indicated by the arrow in the photo. I did not have time to sharpen my skis. It was at the very end of the season, when the active testing of the Ogasaka Triun SL 2019 (next) model year (more details here). Testing was on a hard snow. To the factory sharpening immediately there were questions, so the sharpness was made as outlined in this note. But some “aces” had doubts that the factory angle of 87 degrees is what it takes. Therefore, we have refined both pairs (165 and 155 cm) by 86 degrees (and up to a heap with the continue of sharpness “to the middle of the bend”). I did not notice the difference, but the “aces” said that 86 degrees is much better, now the ski “does not tear off the arc”.

So, I decided to switch to 86 degrees (I ordered a file-guide on AliExpress). And razor sharpness now decided to long “to the middle of the bend”. And problem with the “snacking” of the inner ski I solved during the process of working on increasing the angulation.





Vadim Nikitin DigInfo.ruVadim Nikitin

 

 

 

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