Spring snow, UHMW, and wax

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G-man
Posts: 600
Joined: Sat Mar 25, 2006 3:58 pm
Location: northern sierra nevada

Spring snow, UHMW, and wax

Post by G-man »

There have been other extensive discussions regarding wax vs. no wax on UHMW bases (www.skibuilders.com/phpBB2/viewtopic.ph ... c&start=15), but I decided to start a new thread that focused more on the wet, grabby conditions encountered on warm spring days. Spring can be such a wonderful time to be out on the snow... sunny and warm days, t-shirts and shorts, picnic lunches on the summit. But there seems to be such a narrow window of opportunity to catch the good snow conditions. The snow surface can be a tad too icy before the sun has a chance to warm it up, but if one waits just a bit too long to begin the descent, the snow gets too wet and it grabs at the ski bases, constantly trying to pitch the rider over the handlebars.

I've tried every 'spring conditions' wax there is and some have helped a bit and some haven't. But, none have eliminated the grabbiness to the point where I felt that I could let my guard down and just ski without the feeling that the brakes could be applied at any unexpected moment and over I'd go.

The above thread link made me decide to do some testing of my own. About a month ago, I made a pair of skis on which I didn't sand or grind the bases after they came out of the press. Instead, I carefully scraped them with a series of very fine cabinet scrapers. After scraping, the bases looked smooth and shiny, but there were very small fibers (that had been raised by the scraper) that tended to trial off in the direction that the scraper had been drawn (tip to tail). No matter how carefully I used the scraper, I could never completely eliminate these fine little 'hairs'.

The first day out on the skis was a perfect sunny and warm day at Mount Shasta's little ski park. Early runs were quite nice, but the day heated up quickly and it seemed that in the space of one run, the skis started grabbing pretty severely. I soon ended up getting a stick of yellow wax from my pack, crayoning it on, then skiing a few more runs until the wet muss just became too impossible to ski. The important point here is that the yellow wax improved the glide significantly over the bare base (at least for a little while).

So, back to the shop to build another pair of skis. This time, I paid special attention to being as careful as I could to keep the smooth factory base surface just as factory fresh as possible. When the skis came out of the press, I was very careful not to scratch the base surface while doing the trimming and finishing details. When the skis were mounted and ready to hit the snow, the bases looked just they did when they came off the roll from the factory.

Yesterday was our annual Backcountry Ski Patrol get together. There were about 20 very good tele skiers, on close to 20 different makes of skis, with 20 different base treatments. Skiing was on a 5 day old 2 foot wet dump that hadn't cycled to corn yet, pretty much all on a 30 to 40 degree slope, sunny and warm... another perfect test day. These folks are all 'balls to the wall' skiers and it takes some really bad conditions to make them call it a day. I think many of them got a little tired of me asking, "are you sticking yet?" because I couldn't tell if the snow was getting sticky or not. The fact was, I couldn't tell whether the snow was getting grabby or not because my skis were so slippery that I could hardly stand in one spot when we stopped to chat... I just wasn't used to being on such slippery ski bases.

At the end of the day, most reports indicated that the snow conditions hadn't gotten super sticky and grabby for my fellow skiers, thanks probably to some light cloud cover that came in periodically. However, pretty much all of them did report experiencing some degree of sticky snow at different times through the day. Many of us eventually split off into different smaller groups to ski different aspects of the mountain. My group got into some horribly deep, wet conditions and although the turns were quite exhausting, my bases were nothing but fast. Others who skied this route during the same period of the day had a terrible time with their bases grabbing.

So, whats it all mean in terms of wet warm snow, UHMW, and wax. One day's experience is far from being a very scientific study. I know I'll be grabbing these skis for any ski trips that remain this spring season. It was such a joy to not have to be concerned with the brakes being unexpectedly applied at any moment. I don't know if there is a way to scrape a base without leaving the little 'hairs' of polyethylene on the surface. Maybe a wet sanding with a very fine grit paper would help to get rid of them. I did get some base surface marring yesterday... I'm not even sure what it was from, but on a really unblemished base, every little thing shows up. So, over time and use, even these bases would need some sort of refurbishing to regain their 'like new' performance.

Anyway, just thought I'd share the results of my latest little test.

G-man
powdercow
Posts: 76
Joined: Mon Jul 31, 2006 1:35 pm
Location: Orem, Utah

Post by powdercow »

G-man -

I am so glad that someone else experiences what I call the roller coaster effect as much as I do (when a coaster comes to a stop suddenly and everyone gets whiplash). Saturday in Mineral basin (snowbird) I felt like I was just waiting to be pitched.

Also you beat me to it again. I was thinking about putting one ski of my next pair through the normal base prep process and leaving one untouched. Your method is much more practical. I might just leave this pair untouched, if it doesn't work for me I can always grind them down eventually.

One additional thought: When I was struggling with the grabiness I thought that I might be getting a suction effect on the wet snow due to lack of a proper "structure". If your untouched bases are slightly uneven then that might allow them to break the seal and thus defeat the suction. It sounds like a stretch and seeing what you do, your bases are probably very flat to start with but it might be interesting to go over them with a true bar. I will be interested to hear how they slide on midwinter snow (next season).

Thanks for the info, you always have something good to add.
- Ben
teleman36
Posts: 79
Joined: Sat Dec 30, 2006 7:22 pm
Location: new england

SPRING SNOW, WAX, BASE PREP

Post by teleman36 »

structure is your friend. Ihave had no grabbiness issues on my bases this year,{this is the first year of building]. After many years of tuning my kids race skis every week, sometimes six pairs a night I started having Roy at Strands Ski Shop in Worcester MA. just flatten only the bases on the Montana. This would also put in a great structure pattern. Cheap 10-15 dollars, and would save hours at the tuning bench. I have him do the same on my homebuilts, just a flatten and structure, then i can concentrate on the edges. Yellow wax hot applied, scraped with plexi scraper. I use a snowboard scraper which gives me much more sharp edge between resharpening and is easier to find on a messy tune bench. One tip on removing the fine hairs left if you have scraped them yourself is to run a 3-4 inch razor blade held perpendicular to the base. This will take off the finest of the fuzz. After scrapping I brush out the base with a nylon and brass combo brush. One more tip; wax your sidewalls as well, it helps. Good luck, and let us know if things work any better.
G-man
Posts: 600
Joined: Sat Mar 25, 2006 3:58 pm
Location: northern sierra nevada

Post by G-man »

Hey guys, thanks for the feedback. Powdercow, actually, I did check the bases for flatness after they came out of the press and they were surprisingly flat... just a slight bit of light peeping under the bar along the steel edge 'tooth' area in a few spots. As the base material comes from Durasurf, it has a slight 'micro texture' on it, so it isn't smooth like glass and maybe the factory texture helps to prevent the 'suck' issue. Teleman36, I have to admit that I've never had a professional structure job done on any of my skis. One of these days, I'll have to try it. Great tip on using the razor blades for removing fine UHMW hairs.

Mostly, I've just been curious about some of the theories brought up in the link mentioned above, so I decided to test some of them myself. I don't know if the testing will lead to anything significant, but it's fun to mess around with different ideas... I guess fun is important, eh? I still plan to get a bunch more time on the bare bases over the next month or so.

I didn't do a very good job of making it easy to access the above link. Great microscopic pics from davide there. Here it is in a more accessible format:

http://www.skibuilders.com/phpBB2/viewt ... sc&start=0

G-man
powdercow
Posts: 76
Joined: Mon Jul 31, 2006 1:35 pm
Location: Orem, Utah

Post by powdercow »

G-man

We are thinking the same way. The test I had planned was also in response to the article you posted.
It makes me a little bit giddy to think that I could have a ski that is always fast and requires no base maintenance. If something goes wrong I can always grind and prep the bases later, really a no lose situation.

I figured that your bases came out flat. Mine needed a little bit of work, so it will be interesting to see if I can get them flat enough that I can leave them untouched. I will post again when I get a chance to try the concept out (might be a while).
- Ben
davide
Posts: 260
Joined: Wed May 04, 2005 7:13 am
Location: Tsukuba, Ibaraki-ken, Japan
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Post by davide »

G-man, thanks for your test.
I made a pair recently using base with the non treated side and I had in mind to do some stone griding to improve the structure, but it looks like the little grooves barely visible on the smooth surface are working great.
I should go testing them soon.

I took few more pictures with the electronic microscope.
This is the treated side:
http://aeg.isuisse.com/img/SEM/treated2.jpg

This is the smooth, non treated side:
http://aeg.isuisse.com/img/SEM/smooth2.jpg

and this the treated side after some stone griding:
http://aeg.isuisse.com/img/SEM/sg2.jpg
It looks almost as shine and smooth as the non treated one.
I used a 2 euro griding stone mounted on a drill. The stone is only 2 cm long (4cm diameter) and it is not good for a full ski, so I worked on a little patch.
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