Making Ski Bases

T

tom.Whistler

New member
Hello All,

I have a question about the manufacturing of ski bases. Can anyone share with me details about how UHMW (Ski base) is treated? Specifically, I am looking for information about process used to provide the finished that is found on the bottom of a typical downhill ski or snowboard.

I have worked with UHMW in the past (in a manufacturing context) and I have gotten a hold of some ski base from skilabs.com (a website that sells ski materials for small scale production) and the two differs.

The ski base appears to be sanded on the top side to aid bonding with the fiberglass, but on the other side (the bottom of the ski) the base has clearly been treated in some way (I assume this is done to reduce friction/ increase wax absorption, etc). How is this done?

I have tried looking this up on google, but I haven't had much luck. What I did find mentioned that the UHMW used for ski base is sometime flame treated. However, there was no details about how this flame treatment worked (ie temperatures/color of flame used, duration of treatment, etc) or if this flame treatment was part of the process used to treat the top of the base material to aid with the bonding to the fiberglass, or if it was part of the process used to provide the finish to the bottom of the ski/board.
 
The smooth side of the base material isn't meant to be the final sliding surface. That's just how it comes from the manufacturer. After the ski is pressed, that smooth side is sanded and structured so it can better accept wax, and negate a suction that a ski can create while sliding.
 
13243251:NinetyFour said:
The smooth side of the base material isn't meant to be the final sliding surface. That's just how it comes from the manufacturer. After the ski is pressed, that smooth side is sanded and structured so it can better accept wax, and negate a suction that a ski can create while sliding.
Click to expand...

But it (the UHMW) is treated in some way to better absorb wax isn't it. I couldn't just take a "regular" piece of UHMW, grind it down and wax it, could I?

Any thoughts, if not I'll just go and try it.
 
UHMW HDPE doesn't absorb wax, so you can forget about that aspect for a start.

Essentially it's just a piece of (usually) sintered plastic with a structure ground into it.
 
13243352:rozboon said:
UHMW HDPE doesn't absorb wax, so you can forget about that aspect for a start.

Essentially it's just a piece of (usually) sintered plastic with a structure ground into it.
Click to expand...

sintered bases actually do absorb wax since there are very small pores that are created from the pressing of the base (sintered bases usually start off as a powder if I remember correctly). It is not on the level of a sponge obviously. I guess its technically not absorbing it, rather the wax fills in the pores and makes contact with the snow instead of the base material itself (from my understanding). If anyone who understands this more or knows the exact science behind this, feel free to show me up.

so yea, I didn't need to post since the quote said that
 
13243483:parkplayground said:
sintered bases actually do absorb wax since there are very small pores that are created from the pressing of the base (sintered bases usually start off as a powder if I remember correctly). It is not on the level of a sponge obviously. I guess its technically not absorbing it, rather the wax fills in the pores and makes contact with the snow instead of the base material itself (from my understanding). If anyone who understands this more or knows the exact science behind this, feel free to show me up.

so yea, I didn't need to post since the quote said that
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This is a commonly held skiing myth. A molecule of your average ski wax is considerably larger than the intermolecular spaces in a sintered ski base.

This has all been hashed out on here before, but see this study:
http://www.primateriasport.se/PDF/Peter_Sturesson_examensarbete_skidfriktion.pdf

There are SEM photos of base material on pages 19, 20, 21... they show that waxing (as a process) does smooth out the imperfections in the base, improving glide, but the actual coating of wax on the base is pure film adhesion and pretty minimal, as in it's gone within a few runs on hard snow. However it's still totally worth doing if you're like, a racer or something.
 
13243551:rozboon said:
This is a commonly held skiing myth. A molecule of your average ski wax is considerably larger than the intermolecular spaces in a sintered ski base.

This has all been hashed out on here before, but see this study:
http://www.primateriasport.se/PDF/Peter_Sturesson_examensarbete_skidfriktion.pdf

There are SEM photos of base material on pages 19, 20, 21... they show that waxing (as a process) does smooth out the imperfections in the base, improving glide, but the actual coating of wax on the base is pure film adhesion and pretty minimal, as in it's gone within a few runs on hard snow. However it's still totally worth doing if you're like, a racer or something.
Click to expand...

im not talking on the molecular level, and that I will definitely look into that study when I have time.

As for using wax on bases, they do give bases more speed. So you take a dry base which has seen a lot of use without being waxed, then you melt some wax on it and it clearly gives the base some speed and "moisturizes" the base in a sense. You would be right when you say the wax itself is gone within a few runs, but the wax isn't meant to stay. the chemicals in the wax are what creates the properties that people associate wax with doing. Wax is just a used as a method of transportation to apply the chemicals to the bases effectively. I learned this after trying to wax some candle onto my base and I was told by my shop tech a brief science behind wax and its properties.
 
Apologies to your ski tech but they clearly don't know fuck all about science, hydrocarbons, or anything about wax that wasn't an urban myth passed on to them after years of repetition.

All that about chemicals in the wax, blah blah... all bullshit. "wax" is the solid state of a complex hydrocarbon. When you melt it, it doesn't change composition, it doesn't release anything or change into anything else, transport anything or deposit anything (other than itself) upon the ski.

It's like water - if you freeze water, it's still H2O, it's just solid rather than liquid.
 
fair enough. That does make sense, so I can't have a competent arguement, especially after reading the second link. I will however ask why I have felt substantial differences between certain wax types on different snow surfaces, and I also find a huge difference between a freshly waxed base compared to a few week old base. I also know I am not the only one with these results. I also don't think you would have an argument to say that the wax companies and shop techs selling the stuff have just saturated our perception on the matter with their BS marketing and tech lingo (although it seems to have had an effect on me).

I understand there is a science, but the results speak for themselves, and science is all about the process to get the results, so I can understand your viewpoint since it is clearly in bias of the scientific view. I however prefer definitive results, and I see results. Do you have any explanations?
 
As per the above studies, a good wax job will leave a film adhesion layer that survives for a few thousand (
 
Well, cool, the forum apparently threw away my rather long post...

tl;dr: Waxing provides performance benefits that last maybe 5000m on a good day. Different wax will work differently with varying snow conditions, primarily due to hardness, but once it comes off the base it doesn't do anything - we just don't notice because it happens gradually over about 10 runs or so, compared to going from unwaxed -> waxed which is instant.

All the pore/absorption stuff is myth. Even the wax companies don't really talk about it any more.
 
Thanks for all the comments, I didn't mean to re-hash the bases absorbs-wax/ doesn't absorb wax debate, so let me re-word my question

13243299:tom.Whistler said:
But it (the UHMW) is treated in some way to better absorb wax isn't it. I couldn't just take a "regular" piece of UHMW, grind it down and wax it, could I?

Any thoughts, if not I'll just go and try it.
Click to expand...

Will a ground piece of HDPE after being waxed (in the usual manner) perform like any other ski base?

This seams to be what Rozboon is saying, is this the general consensus?
 
13246406:tom.Whistler said:
Thanks for all the comments, I didn't mean to re-hash the bases absorbs-wax/ doesn't absorb wax debate, so let me re-word my question

Will a ground piece of HDPE after being waxed (in the usual manner) perform like any other ski base?

This seams to be what Rozboon is saying, is this the general consensus?
Click to expand...

My guess is that it would perform differently - ski base material is usually extruded or sintered.

You could just use wood and keep it old school.
 
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