Myths about UHMW Base Material and New Base Material Idea

[Mike Thomas]

Wow... Cool thread! Love the re-examination of things we think we know! That's when breakthroughs happen.

My question... I guess if wax technicians don't understand why something is working, but something they're doing or applying results in a faster ski, can't this be fairly easily tested?

Isn't that pretty much the whole point? Whether or not UHMW is actually porous or not seems like a silly debate to have (for skiers). Wax makes a huge difference, it is easy to test and observe. If a better base material exists or can be made, I'm all for it... but in the meantime, I know wax makes my skis work better, so does base structure. That is all that matters to me.

 

[cantunamunch]

Isn't that pretty much the whole point? Whether or not UHMW is actually porous or not seems like a silly debate to have (for skiers). Wax makes a huge difference, it is easy to test and observe. If a better base material exists or can be made, I'm all for it... but in the meantime, I know wax makes my skis work better, so does base structure. That is all that matters to me.

I'm with you but only sort of. You're right that attempting to achieve a final conclusion through debate is a bit like Karl Linne aka Linnaeus aka the guy responsible for those Latin biology names debating the winter behaviour of swallows and swifts, as in which lakes they sleep at the bottom of.

 

[Mike Thomas]

Well, I'd say it's a bit more like him saying "I've spent many winters here and I don't see swallows or swifts. I know they're physiology and requirements for habitat, it's too cold in winter here, so they can't exist." ... but we know they do- in summer. Pores in ski bases might not exist, but I've seen plenty of race skis with enough wax penetration to discolor clear ptex with the color of the base prep wax, discoloration which doesn't go away when the surface is cleaned (or ground). Something got that color in there. Same with wax. I don't know how wax 'works' but I know a hot wax lasts longer and is more effective than a buff wax and a hotbox or thermo wrap is more effective than a hot wax. I don't know 'why' but I know that is true.

(OK, I'll agree that I might be wrong and all of my experiences with wax was simply me wanting to believe... but... yeah, no.)

 

[Doug Briggs]

I have nothing to add to the technical discussion here but I do have this to add:

1) In the 70s, Rossignol (and likely others) added particles of Teflon to their base material presumably in hopes of it making skis faster. These were extruded bases (I believe) and resulted in a speckled appearance. I wish I had a pair to show, but alas, my old skis just have plain gray bases. As they didn't do the Teflon thing for long, I'm guessing it didn't make a difference.

2) I am quite impressed by the quality of discussion going on here. Wax and base discussions are usually a very heated topic (pun intended). We are 4 pages in and no one has 'shouted' once. Hurrah!

As a ski tech what I've gleaned is that:

• wax makes a difference
• wax doesn't fill pores, but does find the amorphous (vs crystalline) areas in a sintered base and that aids in a mechanical, not a chemical bond of wax to the ski
• structure aids in the mechanical bonding of wax to the base
• our current base products are subject oxidation commonly referred to as base burn

On a side note, when I wax for DH, my major consideration for hot wax is snow temp and humidity. Structure is also very important, but I only have a couple pair of speed skis that I use so huge variations in structure are not an option. Overlays are put on up to three deep with the first layer intended for the bottom of the course, the middle layer for the middle of the course and the last applied layer for the start and top. That said, I'm glad I have wax sponsors because I put between 10 and 30 dollars of overlays on for a single run.

 

[Tony Warren]

Wow... Cool thread! Love the re-examination of things we think we know! That's when breakthroughs happen.

So, I'm not an engineer. I've always looked at the issue as one of basic fluids and boundaries... a golf ball is dimpled. The America's Cup trimaran experimented with bubblers to break water from the ama hull surfaces. If I recall, it was very effective, but against the rules, and of course, very costly. I always thought structure was about optimizing the ski base's ability to move water molecules with less friction, not really to hold wax at all... micro drops vs micro puddles, etc... I always thought wax was more about 'snow' than the ski base.

The golf ball, the problem is air. The boat, water. Our skis, the snow... Fluid dynamics... It seems Tony that you're looking at things from the contact material and working back toward the fluid. My question... I guess if wax technicians don't understand why something is working, but something they're doing or applying results in a faster ski, can't this be fairly easily tested?

On an anecdotal note, I've used rain-x with great success for that one run down back country non-isothermic snow when temps are well above freezing. Just thought it might work after seeing what it did on the windshield a la beading and significantly lowering the coefficient of friction between the water and glass. It seems to last for about 1 run of maybe a 2500 to 3000' of vertical and never interfered with skin glue. Apologies for the poor descriptions above. In my best McCoy voice," dammit Tony, I'm a skier, not a scientist!"

Great comments. Thank you. The rain-ex experiment you did I think confirms my thinking about the hydrodynamics issue. It is about the differential between the surface energy of the base and the surface tension of the water. Rain-Ex creates a very low surface energy coating which does not allow the water to adhere to the surface.

By the way, I found your description to be perfectly understandable, which I think means you are more articulate than you think you are. Thanks again.

 

[Tony Warren]

Well, I'd say it's a bit more like him saying "I've spent many winters here and I don't see swallows or swifts. I know they're physiology and requirements for habitat, it's too cold in winter here, so they can't exist." ... but we know they do- in summer. Pores in ski bases might not exist, but I've seen plenty of race skis with enough wax penetration to discolor clear ptex with the color of the base prep wax, discoloration which doesn't go away when the surface is cleaned (or ground). Something got that color in there. Same with wax. I don't know how wax 'works' but I know a hot wax lasts longer and is more effective than a buff wax and a hotbox or thermo wrap is more effective than a hot wax. I don't know 'why' but I know that is true.

(OK, I'll agree that I might be wrong and all of my experiences with wax was simply me wanting to believe... but... yeah, no.)

I may have an explanation of the colour in clear base. The very finely ground pigments are held in place by weak Van Der Wall forces. They stay in the base because they are ground in deeper by the grinding process and the small amount of melt that occurs in the surface of the base as a result of the friction of the stone or paper on the base.

QED

 

[Tony Warren]

I have nothing to add to the technical discussion here but I do have this to add:

1) In the 70s, Rossignol (and likely others) added particles of Teflon to their base material presumably in hopes of it making skis faster. These were extruded bases (I believe) and resulted in a speckled appearance. I wish I had a pair to show, but alas, my old skis just have plain gray bases. As they didn't do the Teflon thing for long, I'm guessing it didn't make a difference.

2) I am quite impressed by the quality of discussion going on here. Wax and base discussions are usually a very heated topic (pun intended). We are 4 pages in and no one has 'shouted' once. Hurrah!

As a ski tech what I've gleaned is that:

• wax makes a difference
• wax doesn't fill pores, but does find the amorphous (vs crystalline) areas in a sintered base and that aids in a mechanical, not a chemical bond of wax to the ski
• structure aids in the mechanical bonding of wax to the base
• our current base products are subject oxidation commonly referred to as base burn

On a side note, when I wax for DH, my major consideration for hot wax is snow temp and humidity. Structure is also very important, but I only have a couple pair of speed skis that I use so huge variations in structure are not an option. Overlays are put on up to three deep with the first layer intended for the bottom of the course, the middle layer for the middle of the course and the last applied layer for the start and top. That said, I'm glad I have wax sponsors because I put between 10 and 30 dollars of overlays on for a single run.

Hi Doug. Teflon particles in UHMW was first used for industrial purposes. The result was lower tensile strength UHMW as the poly would no bond to the fluorocarbon. The result was good early wear properties with a cascade of failure as the teflon was mechanically dislodged from the UHMW and the voids left created footholds for slurry particles to work on the low grade UHMW. It was a nice try.

Wax does make a difference but its effects are very short term. Thus you get one run on a downhill. My observations when we tested on DH and SG for the Canadian National Team was that all the wax burned off from the edge outward at least 1 cm before coach's corner at Lake Louise. At the finish there was essentially no wax to be found when we scrapped the ski base and cooked it to precipitate out the wax from the UHMW. I observed 'bluing' of the steel edge under the foot and vaporization of the base where the edge got hot. Wax is important for a competitor but of little use for even the most high performance skiers outside of the world of racing.

Testing ski bases on snow is difficult in real life. What we will do is create a Design of Experiment plot matrix to find out what the dependent and independent variables are. This will likely result in the need to make hundreds or even thousands of runs to get an idea of what works and what does not.

There is an article in the thread that should disabuse anyone of the idea that wax penetrates the amorphous regions in UHMW. Wax molecules are pretty small, but way too large to fill those regions. Wax cannot penetrate the base.

I believe that wax can become mechanically entangled in the 'structure' of a base, but is gone in one or two runs. We see wax in the centerline of the base tip to tail after a day of skiing. This is a result of us never running a flat ski. It the centerline of the base is rarely in the snow, so it does not wear out. The edges areas are always dry of wax.

I believe and hope to prove that a very hard yet flexible base that is polished is faster than any polyolefin alternative.

If you want I can call you a name or something, but this thread is high level, one of the best I have ever seen.

Cheers,

Tony

 

[Doug Briggs]

@Tony Warren, You may call me anything you want, just don't call me late for dinner.

 

[Tony Warren]

@Tony Warren, You may call me anything you want, just don't call me late for dinner.

I'm going to stick with Doug

 

[Doug Briggs]

Sure thing, Chuck. ;-)

 

[markojp]

My trigger is 'Shirley'.

 

[mdf]

We see wax in the centerline of the base tip to tail after a day of skiing. This is a result of us never running a flat ski. It the centerline of the base is rarely in the snow, so it does not wear out.

This got me to thinking. I "know" that wax does something that lasts at least a day because of how my skis feel after rewaxing mid-way through a vacation. But the big difference is noticeable during those rare instances when skis ARE flat ... trying to glide across a flat section or shuffling in the lift maze. So I will have to reconsider. Maybe it does wear off the active area really quickly.

 

[Tony Warren]

My trigger is 'Shirley'.

You jest!

 

[Tony Warren]

This got me to thinking. I "know" that wax does something that lasts at least a day because of how my skis feel after rewaxing mid-way through a vacation. But the big difference is noticeable during those rare instances when skis ARE flat ... trying to glide across a flat section or shuffling in the lift maze. So I will have to reconsider. Maybe it does wear off the active area really quickly.

Once you realize that there is no way in physics for the wax to penetrate at all into the base, whether the base itself or the hair-bits of the structure it is easy to figure out that the wax isn't going to hang around enough to do much after more than a run or two.

When I raced I used to wax my skis every time I skied. When I raced full time I only waxed for races. I was a good waxer and my skis were often very fast for about two slalom runs. But when we just practiced 5 hours a day, the wax as just gone and me nor my compatriots worried about it at all. So in about 1975 it was rare that I would do much waxing at all. I tuned the edges, flattened the base and scraped it flat. The 'new' waxes did not seem to be very fast at all.

This is where the germ of the idea of a different base started.

Up the thread there is a great paper by an engineering grad in Sweden. His research confirms my ideas to a great degree. Give it a read and you won't be so keen to waste your money on wax at all.

 

[smoothrides]

I really hope you come up with something faster and more durable in your quest for a new base material, as I think we all want to go faster and wax less.

However, with regard to the current state of ski base materials, I know that there aren't any pores in UHMW, but I also know that as downhill skiers we have edges and high speeds to deal with. The Kuzmin paper I posted earlier deals exclusively with cross country skis. The Kuzmin scraper provides a means to expose flat fresh base, while also imparting some linear structure, but cannot work with edges getting in the way. Also, the high speed and high friction we deal with in downhill skiing cause rapid deterioration of the base material or 'base burn' when not protected with wax. Base burn starts along the edges underfoot, and progresses quickly to the rest of the ski when left untreated. Base burned skis are slow, and if you drip water on the bases it literally sticks. They will not hold wax without exposing fresh material through scraping or grinding, the wax will literally just chip off.

Once fresh material has been exposed the skis will be fast again, and if waxed daily, will stay fast. Maybe the wax is just being held mechanically in the micro texture of the fresh base material, but whatever is happening it works. When working with world cup level CNC stone grinders for racing, you can actually control the shape and depth of the structure so precisely that the tailing edge of the 'cut' is designed as a pocket for wax longevity.

My shop focuses on race tuning, and I have athletes that wax everyday for training and racing, and their skis are always 'greasy,' meaning they have rich, black bases, no burn, and will easily accept wax. These skis feel fast under foot the moment you put them on the snow, and as of now there is no other way to match this result other than frequent waxing for conditions.

Again, I would love to see a new base material that is fast and durable, deals with static and pollution, and is also extremely hydrophobic, but until this happens I think it's wrong to suggest people not wax their skis, when the benefits are immediately apparent even for a recreational skier on UHMW bases.

 

[Tony Warren]

I really hope you come up with something faster and more durable in your quest for a new base material, as I think we all want to go faster and wax less.

However, with regard to the current state of ski base materials, I know that there aren't any pores in UHMW, but I also know that as downhill skiers we have edges and high speeds to deal with. The Kuzmin paper I posted earlier deals exclusively with cross country skis. The Kuzmin scraper provides a means to expose flat fresh base, while also imparting some linear structure, but cannot work with edges getting in the way. Also, the high speed and high friction we deal with in downhill skiing cause rapid deterioration of the base material or 'base burn' when not protected with wax. Base burn starts along the edges underfoot, and progresses quickly to the rest of the ski when left untreated. Base burned skis are slow, and if you drip water on the bases it literally sticks. They will not hold wax without exposing fresh material through scraping or grinding, the wax will literally just chip off.

Once fresh material has been exposed the skis will be fast again, and if waxed daily, will stay fast. Maybe the wax is just being held mechanically in the micro texture of the fresh base material, but whatever is happening it works. When working with world cup level CNC stone grinders for racing, you can actually control the shape and depth of the structure so precisely that the tailing edge of the 'cut' is designed as a pocket for wax longevity.

My shop focuses on race tuning, and I have athletes that wax everyday for training and racing, and their skis are always 'greasy,' meaning they have rich, black bases, no burn, and will easily accept wax. These skis feel fast under foot the moment you put them on the snow, and as of now there is no other way to match this result other than frequent waxing for conditions.

Again, I would love to see a new base material that is fast and durable, deals with static and pollution, and is also extremely hydrophobic, but until this happens I think it's wrong to suggest people not wax their skis, when the benefits are immediately apparent even for a recreational skier on UHMW bases.

UHMW is pretty tough stuff. It takes sustained temperatures above 200 F to cause thermal degradation to occur. I doubt anyone has done an accurate thermoscan of a ski base being run on a world cup downhill, but I doubt that the entire base gets anywhere close to 200 F. Although, like you I have seen degradation around the edges directly underfoot.

I have seen UHMW called Tivar 88 running at about 175 F in fly ash pneumatic materials movement in the 100 tonnes per day range for months on end without needing unscheduled maintenance and replacement. So I am very skeptical about the idea of thermal breakdown of UHMW in ski bases in snow. I would really like to figure out a way to test this idea though. If true, it just makes my idea better because I can formulate hybrid materials with heat sinking ceramics that will operate for two or three minutes well about 400 or 500 degrees.

When I last worked doing work with wax with the Canadian National Ski team I was amazed at how little actual research was done by anybody. We signed NDA's with all the pool wax companies. We also worked extensively with the team wax techs. To be honest I think nearly everything they said was woo woo bullshit. They really didn't know what was going on because no one empirically tests any of their own claims. Even simple test devices to measure coefficient of friction and moisture at the interface were deemed too expensive to bother with.

I am a semi-retired person and doubt I want to spend a few hundred grand of my own money to build these machines without some interest from a ski company or two willing to pitch in. However, that may change.

I have no doubt that you know what you are doing and that you are actually observing the results of your claims. However I doubt the causes. Not because you are necessarily wrong or right in your analysis, but that they are not quantified. With all scientific theory, the main point philosophically is to be able to disprove the theory by empirical means. We are nowhere near at that point.

I take your point on my idea that there is no need to wax skis. Prejudice on my part perhaps.

I want to give you some of my background.

I started selling UHMW for industrial purposes while I was a student back in the mid 70's. I sold it by the truckload all over Alberta and Southern BC. This got me very interested in the field of wear and abrasion as well as tribology. I had a hiatus in the business from 1977 until 1995. At that point my interest changed to finding ways to create adhesive bonds to difficult to adhere to materials like polyolefin plastics. This caused me to learn how to formulate epoxy and polyurethane adhesives, hybrids and variants. Bringing the two ideas together resulted in my creating various types of wear materials that could be applied in situ or machined in the field. I also learned to eliminate all issues with differential thermal expansion between various polyolefin plastics like UHMW and steel or aluminium. In working with designing high wear materials I found ways to create polar bonding sites on some non-organic materials like TiC.

My hunch was that wax did nothing to UHMW because it could not adhere to it at all. It is physically impossible without functionalizing the surface of the UHMW and then, because the wax is so weak that it will does not have either enough polar bonding sites to react with the base, nor does it have the mechanical properties to stay in place for long.

I know a lot of people think wax works very well. I too have experienced this. But I think the time it works well is very short indeed. We will see if I am just another nut with an idea or if something comes from this.

 

[Philpug]

These are the days I miss Ed Chase. Base materials have come so far that we don't realize it because this evolves at a snails pace, well maybe the wrong analogy. Get on an older GS ski, a first generation shape or even a Rossi EX or Dynastar G9 and try to glide. The difference will not only be seen in the clock but it will be felt on your feet. You would be able to glide faster on almost any well prepped all mountain ski. What I am saying bases are still evolving and especially in the race design. @ScotsSkier will tell you there are fast skis and then there are skis that are just ski fast.

 

[Tony Warren]

These are the days I miss Ed Chase. Base materials have come so far that we don't realize it because this evolves at a snails pace, well maybe the wrong analogy. Get on an older GS ski, a first generation shape or even a Rossi EX or Dynastar G9 and try to glide. The difference will not only be seen in the clock but it will be felt on your feet. You would be able to glide faster on almost any well prepped all mountain ski. What I am saying bases are still evolving and especially in the race design. @ScotsSkier will tell you there are fast skis and then there are skis that are just ski fast.

Up until 4 or 5 years ago I had some Spalding Squadra Corse DH in 223 from whenever the heck they came out. They were fast skis the whole time I had them.

In my conversation with the tech guy at Crown plastics, he told me that the only major change they have made over the years was to use higher molecular weight UHMW, which they serve pretty much neet.

I know that since I started working with UHMW lots of modifications have been made, but very few adopted for very long.

My memory is not all that great, but I know that skis seem to slide the same to me throughout the past at least 40 years. Wax absolutely seems to make skis faster but on a temporary basis.

My friend Dave Irwin and Ken Read and the other Crazy Canucks of that era always told me that the Austrian team got the fastest skis and the rest of the teams scrambled around over the left-overs. This continued even after Podborsky and Read started to dominate the sport. I know from my own experience that Race Room rejects in any sidecut are always better than off the shelf retail skis. But I sure don't know why and I doubt it has anything to do with the base or with wax.

But we will see, and we will for sure try lots of waxes to see if they help. At least the waxes I apply will bond at the molecular level.

 

[markojp]

I've heard pretty interesting stories about the manufacture of base materials, where on the role they are, and which manufactures have access to the molicularly 'dense-ist' material via a futures market and investment.

 

[Tony Warren]

I've heard pretty interesting stories about the manufacture of base materials, where on the role they are, and which manufactures have access to the molicularly 'dense-ist' material via a futures market and investment.

Ski bases are a microscopic portion of the UHMW business. I doubt they would have better access to resins than say these guys.

http://www.quadrantplastics.com/na-...175-f/tivar-R-uhmw-pe-family-of-products.html

Who deal with serious abrasion and slide issues involving a vast array of materials. I would guess that they sell more Tivar 88 in a month than Crown has ever sold in the life of the company. I toured UHMW plants in Germany that were a half million square feet in size.

No, I think the base guys buy commodity UHMW resins in the molecular weight that makes most sense for them and their ability to process it.