THERMO BAG

The Toko Thermo Bag is a hot box that works like none other.  It is portable (after 3 minutes of packing up, fully digital, and very effective.  The ventilator ensures consistent temperatures throughout (as compared to homemade hot boxes) greatly reducing the chance of damaging skis.  The temperature controls are digital - simply dial in the desired temperature.  The Toko Thermo Bag also offers digital temperature readouts - desired temperature and actual temperature (which become the same after a short while).  Many World Cup teams own a Thermo Bag as well as many of the world's best ski racers have their own.  The Thermo Bag fits 12 pair of Nordic or 4 pair of Alpine skis (depends some on design of ski).

The Thermo Bag is used for two purposes.  First, to get wax into new or freshly stone ground bases. A soft wax such as System 3 or World Loppet Yellow should be ironed on the ski prior to treatment.  Putting the skis in the bag for 6-8 hours at 62C is appropriate for such a task.  After treatment, it is important to iron in a wax such as System 3 or World Loppet Blue to harden the base up.  Otherwise the base will be so soft, it will oxidize and scratch easily.  It is also a good idea to check the skis after 4 hours of treatment to make sure that there is enough wax left.  If not, they should be taken out, more wax should be dripped on, and they should go back in the bag for more treatment.  An important point regarding wax penetration is that generally a soft wax will go deeper into the base and at a higher percentage.  Once that soft wax makes it in, it is easier for a harder wax to get there too.  Without the soft wax treatment, the bases would never reach such a high degree of wax penetration/saturation.

The second purpose is for race preparation of skis, especially in colder temperatures.  Dibloc HF Blue can be ironed into the ski in the morning, the skis can sit in the Thermo Bag for 4 hours, then the Thermo Bag can be unplugged so the bag (and skis) cool very slowly overnight.  In the morning, the skis need to be scraped and brushed out.  This treatment will yield a superb race day finish.  The most superficial layers of base will have a very high percentage of wax in them as the heat treatment coupled with the extremely slow cooling process will yield this.  This slow cooling is the opposite of waxing the skis and throwing them outside in the cold weather which pushes the wax out of the base.

Rarely, older skis can be damaged by the Thermo Bag at temperatures, especially when treated for too long or at too high temperatures.  This is often because the resin and glues in the skis are no longer consistent and the ski reacts differently to the heat in one part of the ski compared to another.  This can result in warping or collapsing of the base.  However rare, this needs to be considered before treatment in a Thermo Bag.

In evaluating the effectiveness of the Thermo Bag, we needed to be able to measure the amount of wax in the base.  This was accomplished by sliding extremely thin (1/1000mm) pieces of base from skis that were treated with the Thermo Bag and from skis waxed with irons.  We were then able to compare the results. 

The diagram below shows the results.  The triangle boxes show wax penetration in depth and percent of base achieved by ironing at 130 degrees Celsius.  The square boxes show the same with the Thermo Bag on at 60 degrees Celsius for just three hours.  The Thermo Bag treatment resulted in a far higher percentage of wax reaching a far deeper part of the base.