I’m getting a new quiver of skis this year, and as new skis, in the past I would just wax a lot and ski on them a lot. I’ve been thinking about building a hot box for myself, and was wondering a few things.
Does the hot box have noticeable better results for getting a new pair of skis up to speed?
Is there any reason to hot box a pair throughout the season? Can you hot box too often?
Probably most important. Is it worth it to build one?
The heatbox is an interesting phenomenon. When the idea first took hold and started to gain prominence there was a really divided reaction to it. Independent service guys and shops thought it was amazing, but inside the industry it wasn’t considered a big deal. And of course some of the early heatbox protocols destroyed skis, and the ski companies had to answer questions about that!
Since then the industry has come to embrace the phenomenon, and now we see wax companies making specific heatbox wax, and even selling pre-fabricated heat boxes. We don’t have people out there anymore saying that it is inherently evil!
So, let’s consider specifics. Do they work? Well, put simple, yes.
The mechanism for getting wax into solution in the base can work in different ways. With an iron you bring the wax and the base material up to a critical temperature where the wax dissolves into solution in the amorphous zones of the base really quickly – almost immediately. This temperature depends a bit on the base formulation, but it’s pretty high – around 110 degrees C on most bases (at least, that’s the iron temp that results in wax going into solution). This is a bit like dissolving sugar into really hot tea. It works quickly and easily, as long as the tea is hot. The limiting factor here in terms of saturation is the temperature gradient through the base material. As you get into the base, the temperature under the iron will cool off, and when it gets below that critical temperature the wax won’t really go any further. The longer you spend waxing, the further the heat penetrates the base, and the more wax goes into solution. But then we run into issues with the stability of the ski. The resins that hold the ski together release at temps around or just above 100 degrees C, and the whole ski tends to run into stability issues because of the thermoplastic nature of the materials at much lower temps – around 70 or 80 degrees C. Base material is only about 1mm thick when it’s new. So, you can imagine that it’s pretty easy to overheat the laminations under the base, and the core of the ski. With different constructions (brands), this presents different problems.
Using an iron to put wax into the base obviously has limitations. The best strategy is to use the highest iron temperature that the wax can support (this is usually the upper end of the manufacturer recommended iron temp range), and to move pretty quickly. You won’t get a TON of saturation, but you get enough.
Now, the heatbox works differently. In this case we bring the temperature of the whole system up to something right around the melt-point of the wax. We don’t even need the wax to be fully fluid – just sort of gelatinous in consistency. The process of putting wax into solution in this case is very, very slow. It’s like dissolving sugar into cold tea! Sit there and stir, and stir, and stir some more, and eventually it will go into solution. In this case the limiting factor is time. The wax moves into the base slowly, but the whole ski is at the same temperature, so the longer you let the ski sit in the environment with wax on it, the more wax goes into solution.
I’ve done some measurements using a relatively accurate scale to measure how much wax I can put into a ski with an iron. After four or five “waxings” (two trips from tip to tail with a 120 degree iron, using a soft paraffin) I can get about 0.5grams of wax into a 192cm skate ski. In the heatbox it’s no problem to put much more than that in. One layer of wax from my wax roller applied around 2grams, and I can make most of that disappear with a long overnight in the heatbox – so that when you scrape the ski you’re barely getting anything off.
So, of course, if the goal is to get a lot of wax into the ski, then the heatbox works really well. There’s no way to beat it. But it’s worth asking the question – is the goal to get a lot of wax into the ski?
In terms of performance, the answer is that it really doesn’t matter how much wax you have in the ski, beyond a certain level. You only ski on the surface of the base, so that’s where you need to look for your performance benefit! A lot of people point to the durability of the wax job as a big reason for wanting a high level of saturation, but that’s not really right. Durability comes with hardening the base and layering the wax appropriately. It has very little to do with putting a TON of wax into the base.
Many people swear that the skis just get faster when they’re really well saturated. Again, I’ll call BS. I believe that the skis get faster with repeated scraping and brushing, particularly on a factory-produced grind. The base surface that comes out of the automated assembly line finishing process in a ski factory is generally pretty hard. Most companies aren’t straight-up ruining the bases these days, but the performance of the ski will improve with some conditioning, and some hand work. Also, many of the factory structures are pretty aggressive, and they mellow-out with physical work – scraping and brushing – which makes them run better in colder and sharper snow.
The really big reason that I like the heatbox is that it helps to eliminate user-error. When the base is freshly ground, it’s quite vulnerable. Unlike the factory-produced finish that requires a bit of abuse to get fast, the bases that I produce in the grinding process are extremely delicate when they come off the grinder. They need some waxing to harden up, more than anything else. The chance of screwing-up the base at this stage is very high for somebody who doesn’t understand what they’re doing. The heatbox eliminates that. If I send a ski that is well saturated and at least nominally hardened, the customer can scrape off the wax that I ship the skis with, and have a really good experience. I never get complaints about my grinds when customers don’t work on the skis before they go skiing! It’s not uncommon to get complaints about the grinds when a customer has diligently waxed the freshly ground skis 400 times in order to saturate the base.
The other big incentive is money. It’s fully established that the heatbox is a service that shops charge money for. It’s the easiest money you ever made! Put a few pennies worth of wax on the skis, park a bunch of pairs in the heatbox, and let the magic happen. I can put a rack of 120 pairs into my heat box (more of a heat room), and get paid really well to have a good night’s sleep! Of course, that doesn’t sit too easy with me. But, as you’re finding out, I really don’t mind telling people how it all works – it doesn’t seem to have a bad effect on business.
To prepare new skis for racing, I guess the real answer depends a little bit on what base surface you’re working with. When I’m preparing skis that I’ve ground, I can have them ready to race with about three layers of soft wax followed by a “race hardening” layer. This is not a theoretical claim – I’ve done it many times at very high level competition. However, if you’re starting with a factory-produced grind then you probably need a bit more work. Let’s be clear that there are different kinds of “factory” grinds. Every ski company has a racing department that produces grinds, by hand, for the racing program. Usually the assembly-line production grinds use structure patterns that are based on racing department grinds. But by and large the factory-produced grinds DO NOT go in world cup races. When a company claims that a “factory grind” is used in high level competition, they’re talking about racing-department hand-produced grinds. There are exceptions. Kris Freeman had great results in Kuusamo several years ago on a normal production 115 ski from Fischer, with a true factory assembly-line grind. No kidding! But that ski had a plus grind, and had been worked hard and trained on for the whole pre-season. Lots of laps in Muonio on manmade snow. Lots of ironing and scraping by World Cup wax techs. It wasn’t fresh out of the box.
So, is it worth it? Well, when I go skiing I’m usually not on skis that have been in the heatbox. I haven’t seen a circumstance where heatbox skis are demonstrably superior to normally waxed skis. But I’m a pretty good waxer, and I know what I’m doing. I use my heatbox to ensure that my customers have a good experience. And to make money.
I haven’t answered your specific questions. I will do that in short words below:
Does the hot box have noticeable better results for getting a new pair of skis up to speed?
No.
Is there any reason to hot box a pair throughout the season?
Yes. You can use the heatbox to resaturate the skis, and even to apply race wax.
Can you hot box too often?
Yes, but it’s not a problem to use the heatbox frequently, provided temps are low, and the skis don’t spend DAYS in there. Keep it to about 12 hours a week, and you shouldn’t have any problems.
Probably most important. Is it worth it to build one?
If you can get paid by your friends to heatbox their skis? Absolutely!