Idealy you will never have to read this page because you need to. However, enthusiastic skiers are always eager to either start on the snow early before a thick base has established, or continue skiing once the snow base has become too thin. Being an enthusiastic skier is great. Occationally this takes a toll on the ski bases with grooves, scrapes and cuts from rocks and other hard objects.
Minor grooves (less than 1/2mm in depth) that have no sharp edges are probably best left alone. Particularly if the groove runs the length of the ski. The effort is not going to bring a lot of return. If the groove is deep, goes across the width of the ski or bits of the base are hanging loose you likely want to do some minor repairs.
If the skis you are looking to repair are your racing skis and you participate seriously in several races per season grinding may be your choice. Stone grinding is not an at home process. It takes specialized equipment and a fair amount of practiced skill. With cross country skis you should find someone who has experience with cross country skis since they react very differently from alpine skis.
If you are thinking of stone grinding your skis you should talk to the technician who will do the work or read the shop's web page carefully. You should feel comfortable that the job will be done right. A poor or bad grinding job can make the skis useless. A good or excellent grinding job will improve your skis' glide and handling.
The goal is not to remove a lot of wood. Removing a lot of wood can cause a "dish" in the base that is not beneficial to grip or glide or handling. The goal is to perform a light adjustment on the base so that wax, dirt and snow does not clump or stick to the groove. This is for minor grooves.
It is best to place the #100 or #120 grip sandpaper on a professional sanding block. This is the type of sanding block that is flat on one side and curved on the other. For sanding ski bases you want to place the sandpaper on the curved side. Since the ski base has a camber (curve) using the curved side of the sanding block will help ensure an even job.
Pressure on the sanding block should be light. Start about 5cm/2in ahead of the groove and continue about 5cm/2in past the groove. Move from tip to tail with the sanding block working the entire width of the ski. This will help keep the base flat. As you move the curved side of the sanding block along the ski base increase the tilt of the sanding block to expose fresh sandpaper. Many light passes allow for better control.
After sanding wooden skis remove any dust. Then re-tar the sanded areas so that they are protected from water. The tarring page describes this.
Sanding P-tex based skis is not much different than the technique for wooden skis. Instead of using granite/wood sandpaper you should use silicon oxide (SO) waterproof sandpaper. SO sandpaper will make cleaner "cuts" when removing base material and won't loose the "sand" as easily. You should cover the base in soapy water (dish soap 30ml to water 1L) will help lubricate the base for smoother sanding and will also suspend particulate so it does not interfere with the sanding. Of course you won't need to re-tar the base, but you should re-apply base wax (glide or grip as appropriate).
When a deep groove has been made in a P-tex base, particularly width-wise, waxing and using your ski can be more difficult. A serious groove can slow the ski and affect handling. Filling the groove is the best option. If the groove is small and/or shallow it is best to just leave it.
Filling the groove with a base repair candle is the easiest method. They are available in clear or black to match the appearance of most bases. The candles are not the same material as the P-tex base. Therefore the repair area will not absorb wax. However, it can make waxing easier and the physical drag can be reduced.
Clean the groove of any wax, dirt or other material. If possible with a #120 sandpaper lightly roughen the inside of the groove. Avoid roughening outside the groove (this isn't needed). Roughening the inside will help the candle material to adhere. Light the candle with a match while holding the steel scraper under the flame area (to catch drips). The candle will be held horizontally. Once the flame is burning cleanly (a small blue flame; this will take a minute or two) let a drop or series of drops go into the groove. Let the material cool for 15 minutes. Then using a sharp metal scraper make several light passes to remove the excess material. If there is still a groove present you will need to add more candle material before scraping. A hint for improving the adhesion of the candle to the base is to heat the repair area with a hot air gun before dropping candle into the groove.
Strings and hairies are long and short bits of P-tex that have been scraped or peeled from the base but are still attached to the base. Leaving them attached will create a literal drag in the snow and are awkward to work around when re-waxing the ski. The solution is careful removal.
Using a sharp steel scraper come close to the base of the string and use the sharp edge to slice. The ski should be in a ski vice to keep it steady, both hands should be used to control the steel scraper and the area should be well lit for visability. Use the sides of the ski to help with control. Move the scraper along the length of the ski to minimize the effect of any errors. Start will light pressure. Heavy pressure is more difficult to control and more prone to unintended errors (more grooves). Don't be shy asking someone around the wax hut with more experience for some help. Using a sharp steel scraper effectively takes time and practice.
If you have any questions about this web site or it's content please contact
with e-mail to "Askus at SkiWax.ca" (replace 'at' with '@') or
telephone (519) 747-5293.