by Jim Galanes, head coach Alaska Nordic Ski Center, Gold 2002
From the 1999 Fall issue of New England Nordic News
This fall, while we all anxiously await the new ski season, is a good time to get our race skis out of storage and give them a proper reconditioning. If your skis were fast last year, do not assume they will again be fast unless you recondition them to remove the dirt and old wax from the base, and do some basic base maintenance. Old skis that have been properly cared for tend to be faster than new skis because they have been waxed and skied on much more. To keep those old skis fast and to improve those skis that just have not seemed fast follow this simple procedure. The tools you will need to have available to recondition you base are:
The first step in reconditioning your base is to thoroughly scrape with a sharp plastic scraper all of the storage wax that you put on the skis in the spring. Then make 10-15 passes down the base with a brass brush to help lift dirt and oxidized base off the ski. Next make another 10-15 passes with fibertex to clean the loose wax and dirt particles and oxidized base off the ski. You are now ready to begin hot scraping to thoroughly clean the bases. Start by setting the iron temperature about 10 degrees centigrade above the melting point of the wax, or about 100 Centigrade for Star Uniblock yellow. Drip a bead of wax down each side of the grove and iron the ski for 3-5 minutes. While ironing the wax on the base be sure to keep the iron moving and work approximately one half of the ski at a time. With this soft a wax the wax should stay molten on the base for a couple of minutes. While the wax is still molten scrape the wax off the base with a sharp plastic scraper. You can also wipe the wax off with a clean rag or fiberlene. This will pull the dirt and residue out from deep within the base. In the wax you scraped or wiped off you will see the dirt and residue that was in the base. This process should be completed 2-3 times or until you see no more dirt in the base.
After completing a couple of hot scrape applications the ski base should be very clean. The next step should be to evaluate the base for damage, oxidation, burns, nicks, scrapes or unevenness. Using a stiff steel scraper or a truing bar, hold the ski up to a light source and place the truing bar or scraper across the ski every five centimeters to check for base flatness. If the base is flat you should see no light under the truing bar or scraper. If the base is not flat then you either have to metal scrape the skis or if you prefer get them stone ground. Both metal scraping and stone grinding require a highly skilled technician. Either of these options can ruin a good pair of skis if not done correctly so please use caution.
If the base shows signs of burn or oxidation the bases will need to be steel scraped or stone ground to get down to fresh polyethylene. Burned base will look somewhat like the skin of an orange, while oxidized base will appear discolored. In either case when waxing the ski the base will not effectively absorb the wax. In the case of minor oxidation, that occurs due to exposure to air, sunlight, and heat an aggressive fibertexing can remove the oxidized material.
After the bases are flat and free of oxidized or burnt base material, you need to check the edges for nicks. I recommend beveling the edges by lightly holding a sharp steel scraper or sanding block with 220 grit paper, at 30-40 degree angle to the base in the tip and tail and 10-20 degrees over the rest of the ski. If using a scraper very lightly trim the outermost edge of the ski, if sanding a couple of passes over the edge should be enough. The goal of beveling the edge is to take away any nicks or rough edges that will slow the ski and to slightly round the edges to aid in turning and in keeping the ski from excessively edging in the snow.
Once the bases are in top condition then it is time to make a decision on base structure. If you have only one pair of skis you may decide to put in a structure, either by grinding or with hand tools, that will match the condition you most like will have in your early season races. If you have skis for both wet and dry snow you may want to put in the appropriate structure at this time and then begin the final base preparation process. Or you can wait until the race season starts and prepare your skis with the optimal structure for the snow conditions.
After the bases are flat and free from burn or base oxidation, or structured, they should be finished with an aggressive fibertexing. The purpose of fibertex is to remove base oxidation and microscopic polyethylene hairs that occur from steel scraping, sanding, or stone grinding. The fibertexing can be done by hand for 10-15 minutes per ski or for a few minutes with a rotary fibertex device. When looking at the base under a microscope you will find the base covered with polyethylene hair. It is very important for good glide that these hairs be removed. We have done testing at Jenex and have found that traditional fibertex reduces the size of the polyethylene hairs, but also creates more, smaller, hairs. We have tested and found a type of fibertex, the Jenex Omni-Prep system, which has proven to be very effective at removing the polyethylene hair without creating the smaller hairs.
The final step in base preparation is to impregnate the base with wax. In the past it has been thought that the initial base impregnation should be done with a non-fluorinated hydrocarbon wax. In theory this is because the flouro waxes do not have the same molecular structure as the base and does not seem to penetrate the base as well. I recommend starting with a soft hydrocarbon wax, like Star Uniblock Yellow, for the initial 4-6 layers of base wax. Then I progress to a soft low or medium flouro content wax like Star Ultra-Tech Pink or Tekno TF 12. For skiers competing on the national or international level and who demand the best performance from their skis I finish the base preparation, impregnation, process with a soft high flouro wax like Star MB 2, Yellow, formerly Eclipse Yellow. Using these medium and high flouro content waxes at the end of the base preparation phase will improve the bonding of the flouro in the high flouro waxes we will be using in races.
During the impregnation process be sure to use a good iron and set the temperature about ten degrees centigrade above the melting point of the wax - 100 to110 degrees centigrade has proven ideal for optimal wax absorption. Iron each wax application for three to six minutes; depending upon the temperature of the ski it may take as long as three minutes before the base material is ready to absorb wax. Remember, just because the wax is liquid on the base does not mean the base is absorbing the wax. The base material has to first reach a temperature of 100-110 degrees centigrade before it will absorb the wax. It is best to work the ski in sections so as to avoid over-heating the ski and the base. As you are ironing if you see dry sports develop, as the base absorbs wax, add more wax. You never want to run a hot iron over dry ski base.
In the initial stages of base preparation the skis should be waxed, plastic scraped, and plastic brushed at least ten time to ensure optimal performance. After each wax application the skis should be allowed to cool completely, usually 30-60 minutes prior to scraping and brushing. It is possible to reheat a layer of wax, providing it stays clean, and there is adequate wax on the base. I discourage this method during base preparation because I think the scraping and brushing process helps to remove additional polyethylene hairs and creates a faster base.
This reconditioning process may be done a couple of times per year depending upon the snow conditions. Skiing in wet dirty snow will increase the need to clean and recondition your skis on a more frequent basis. This initial step in base preparation will greatly improve the performance of you skis during the winter. Give yourself an edge prior to the race season by taking the time to prepare your skis. Spending the time now to prepare your skis will help you cruise by your competition in the races this winter.
Important Notes: Modern ski bases are all made from polyethylene of various grades and qualities. Polyethylene consists of small crystals, crystalline, surrounded by less structured, amorphous material. When the base is heated some of the crystals begin to melt before the material itself begins to melt at a temperature of 135 C or 275 F. When wax is ironed into the ski base, the molten wax penetrates the spaces between the crystals and the mixes with the amorphous material. This means that we are not only waxing the ski, we are changing the chemical structure of the base itself. Extreme caution must be used when waxing skis with high melting point cold weather waxes and additives and pure Flouro products. Look at the melting points of all the waxes you use and reduce the ironing time as the melting point of the waxes exceeds 120 degrees centigrade.