Biggie! In my opinion you should make a lowcamber ski that is a little stiffer to compensate for the pop.
And now to materials for pop. Be carefull using carbon fiber to increase pop. Carbon fibers have a negative elongation coefficient which means its lengths increases when getting cooled while glassfiber shrinks. This means that if you add carbon in the top of youe ski, as most manufacturers do, camber rises when you take them out and it is even worse if you use it in a heated press.
My advice! Stay away from carbon!
Kelvin!
A soft ski is not affected as much as a stiff ski and this might be one of the reasons why many powder skis have a very soft flex. With a low camber you can stiffen upp the ski a little bit and increase stability on uneven snow a bit.
I could write a book on carbon, but in my opinion carbon is for racing cars!
And do not mix carbon and glassfiber, its like mixing rubber and steel!
Henrik
Hendryx skis
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
Re: Camber
Isn't that exactly what we do? Rubber dampening strip right on top of the steel edges?Henrik wrote: And do not mix carbon and glassfiber, its like mixing rubber and steel!
Henrik
Rubber vs steel!
Hose-man you got a point there but we put rubber between the steel edge and the glassfiber to equalize tensions beetween these two materials. They have different heat elongation constants which means that they contract differently when getting cold!
What I mean with rubber/steel mix is that if you take a bit of rubber and a bit of steel and dimension them so they can take half the strain each and use them together and then start to load them! What happends?
The steel will take all the forces because breakelongations differs so much!
This is the case with carbon-glas mixings! The carbon takes all the forces and if you do not dimension the system correctly it actually gives a weaker construction by adding an ollieband wich will take all the forces and therefore snapp very early.
This is what happend to the surfboard industrie when they started to strengthen their boards with some extra carbon bands! The boards snapped and got weaker!
Henrik
What I mean with rubber/steel mix is that if you take a bit of rubber and a bit of steel and dimension them so they can take half the strain each and use them together and then start to load them! What happends?
The steel will take all the forces because breakelongations differs so much!
This is the case with carbon-glas mixings! The carbon takes all the forces and if you do not dimension the system correctly it actually gives a weaker construction by adding an ollieband wich will take all the forces and therefore snapp very early.
This is what happend to the surfboard industrie when they started to strengthen their boards with some extra carbon bands! The boards snapped and got weaker!
Henrik
Professor!
I agree with your last post about the ollieband Henrik, but there are other ways to use carbon that will not expose it to those maximum tensions in the ski. If you use it as a torsion stiffener (45/45) and the glass in the length of the ski, the differences in the vibration frequencies will dampen the ski, in addition to the incteaced torsion, a 45angled fibre will not reach its maximum tension at the same time as the 0deg. fibre
wow, endre, if i understand well....do you think that if i want to use both glass and carbon, its better to use 45/-45 carbon and 0 glass? Because I was about to use them opposite way!? One local supplier of those fibers recomended to use 45/-45 fiberglass with some layers of unidirectional carbon running lenghtwise the ski...hmmmm...now i don´t know... 
No! It should be the other way as carbonfiber has a negative elongation coefficient. It means that carbon expand when temperature decreases and vice verse. Carbon in the bottom gives a lower camber at lower temeperatures.
For a +-45 degree carbon the increased break elongation would be the root square of 2, 1,42, times its break elongation. That will be around 2 % for a carbon with 1,5 % elongation. Best carbon yhat I know has a break elongation of two %, extrem high tensile. E-glass is about 5,5 % and S-glass is about 6,5 %.
So far, I am going for glass! I have tried to break my skis but I could not. They just bent like crazy. I think I can bend the tips together on my skis!
Henrik
For a +-45 degree carbon the increased break elongation would be the root square of 2, 1,42, times its break elongation. That will be around 2 % for a carbon with 1,5 % elongation. Best carbon yhat I know has a break elongation of two %, extrem high tensile. E-glass is about 5,5 % and S-glass is about 6,5 %.
So far, I am going for glass! I have tried to break my skis but I could not. They just bent like crazy. I think I can bend the tips together on my skis!
Henrik
Professor!
No I can not bend them together but what I mean is that the skis will bend this much and not break!
What I did is that I place my skis in a deep ditch with an angle of ~60 degrees in the bottom and, this was hard to my heart, jumped on them. The skis were standing like an U but they did not even give a sound of that I was reaching the break point. This day it was more than 30 degrees celsius in the shadow and you should not perform these tests when hot as glass fiber is much stronger when cold!
And about carbon, it is not very good in taking kompression!
Henrik
What I did is that I place my skis in a deep ditch with an angle of ~60 degrees in the bottom and, this was hard to my heart, jumped on them. The skis were standing like an U but they did not even give a sound of that I was reaching the break point. This day it was more than 30 degrees celsius in the shadow and you should not perform these tests when hot as glass fiber is much stronger when cold!
And about carbon, it is not very good in taking kompression!
Henrik
Professor!
hi everyone!
i haven't had a chance to read over all the comments related to this thread, so i might sound out of place. but i do think the camber discussion is really interesting. i'll try to contribute more soon. i have a few words to say about skiing on the Kaffeines (25mm of camber) and the Stiff Upper Lips (same ski, but with much less camber).
anyway, i'm at Whistler, BC right now. i brought with me 5 pairs of skis. conditions are relatively nice for early season. groom runs are hard, with patches of ice in the high traffic areas. some groomers are definitely carveable though. between Blackcomb and Whistler, Whistler is my favorite. i spend most of my time in the upper bowls of Whistler (Harmony and Peak chairs for those familiar with the area). there's new snow, between 6-12" on top of a firm base in the bowls and on steeper terrain. the base layer, however, feels like a re-frozen melt-freeze, but in some spots the snow is deep enough and it's hardly noticeable. the base isn't thick enough to cover rocks yet...
the snow isn't deep enough for the Upper Krusts. instead i decided to test the difference between the Kaffeines and Stiff Upper Lips. both of these skis are made of the same materials and they have the same shape. the only differences are (1) the Kaffeines have at least 25mm of camber and the Stiffs have between 12-15mm and (2) the Kaffeines have a layer of titanal directly above the ski-base material (and below the wood core) and the Stiffs have it directly below the top-sheet material (and above the wood core). Kelvin did me a favor by base grinding the Kaffeines and putting a nice layer of wax on them (thanks Wu!). because of the camber, i decided to add a 0.5-degree bevel on the top and both third of the edges. underfoot was left untouched, at 90-degrees. i was hoping that the bevel would help compensate for the camber during turn initiation.
i started the first half of the day on the Kaffeines. before hitting the snow i noticed the camber! the Kaffeines have at least 25mm of camber ridiculous. i had a hard time carrying them around because the camber made them hard to "squeeze" the skis together; they stressed my hands and occassionally would "spring" apart. i finally had to use a velcro ski-strap to keep them together during transportation. anyway, remember this photo of Kelvin holding the Kaffeines?
the first run was from the top of Emerald chair down a groomed blue run. i wanted to have a chance to feel them before taking them on steeper and more varied terrain. the first half of the run i keep my heels down and drove them alpine style. the first thing i noticed was they had a smaller "sweet" spot than most skis i've been on. i had to stay more balanced over the skis to get them to turn. after ten turns or so i felt comfortable, but the skis definitely needed some attention. i noticed they weren't very comfortable going straight. they were happy on edge, turning, and with active pressure applied (most likely to "de-activate" the effects of the camber). but even during the turn they needed attention. i think Kaffeine is a good name for them because they definitely kept me awake...at all times. a few turns later i decided to let them run but still with my heels fixed. i was able to push them and they carved beautifully, but with attention of course.
for the second half of the run, i decided to tele turn them. the camber seemed to make them feel a bit awkward. at first they wanted to resist the style of turning, but with i found a balance and pressure point to get them to behave. again, they didn't not like going straight. i had to keep them turning.
my thoughts after the first run: a great ski, in terms of the turning radius, dampness, and stiffness. and when they behaved, they were great! (Kelvin, i think we have a winner here, modulo the camber). the only thing i didn't like was they felt a bit unpredictable. sometimes they had a mind of their own and would track off trajectory. turn initiation need some effort at times.
next, i took them into soft snow and varied terrain. they skied the 6-12" of powder that we found great, as long as i kept them turning. when i relaxed and tried to make more gentle turns, they wanted to submarine and run off. here's a video that Chris Cass made with his small point-and-shoot camera.
http://www.skibuilders.com/gallery/kaff ... istler.wmv
for whatever reason, on more or less flat terrain like cat-tracks and traverses, the Kaffeines were so slow. i wonder if the camber has any affect. i struggled to keep them moving when the terrain eased off. they skis were freshly waxed.
at half-day, i switched over to the Stiff Upper Lips. this is pretty much the same ski. i immediately noticed how easy they were to turn; they were significantly more predictable and fun to ski. i didn't use as much energy to keep them under control; i didn't have to "fight" as much compared to the Kaffeines. however, i did notice that the Stiffs were not quite as "positive" as the Kaffeines in terms of carving on hard snow. i almost want to say that i like the feel of the Kaffeines better (except the camber); they felt more solid. but the Stiffs were more forgiving. i wonder if it's related to the camber or the location of the titanal or both? as for gluiding abilities on traverses and cat-tracks, the Stiffs were great. in contrast, the Kaffeines were slow for whatever reason...
in summary, between low and high camber, i think low camber skis are more user friendly. they feel more predictable. in terms of skiing in powder, based on my experience, high-camber skis tend to submarine when they are not actively turning. i got into trouble when i was trying to straight-run or when i was trying to make more gentle turns (applying less pressure). again, i found they were slow too on flat stuff - i'm not sure if this is a camber-related issue.
the next thing to try is a soft ski with lots of camber....
i haven't had a chance to read over all the comments related to this thread, so i might sound out of place. but i do think the camber discussion is really interesting. i'll try to contribute more soon. i have a few words to say about skiing on the Kaffeines (25mm of camber) and the Stiff Upper Lips (same ski, but with much less camber).
anyway, i'm at Whistler, BC right now. i brought with me 5 pairs of skis. conditions are relatively nice for early season. groom runs are hard, with patches of ice in the high traffic areas. some groomers are definitely carveable though. between Blackcomb and Whistler, Whistler is my favorite. i spend most of my time in the upper bowls of Whistler (Harmony and Peak chairs for those familiar with the area). there's new snow, between 6-12" on top of a firm base in the bowls and on steeper terrain. the base layer, however, feels like a re-frozen melt-freeze, but in some spots the snow is deep enough and it's hardly noticeable. the base isn't thick enough to cover rocks yet...
the snow isn't deep enough for the Upper Krusts. instead i decided to test the difference between the Kaffeines and Stiff Upper Lips. both of these skis are made of the same materials and they have the same shape. the only differences are (1) the Kaffeines have at least 25mm of camber and the Stiffs have between 12-15mm and (2) the Kaffeines have a layer of titanal directly above the ski-base material (and below the wood core) and the Stiffs have it directly below the top-sheet material (and above the wood core). Kelvin did me a favor by base grinding the Kaffeines and putting a nice layer of wax on them (thanks Wu!). because of the camber, i decided to add a 0.5-degree bevel on the top and both third of the edges. underfoot was left untouched, at 90-degrees. i was hoping that the bevel would help compensate for the camber during turn initiation.
i started the first half of the day on the Kaffeines. before hitting the snow i noticed the camber! the Kaffeines have at least 25mm of camber ridiculous. i had a hard time carrying them around because the camber made them hard to "squeeze" the skis together; they stressed my hands and occassionally would "spring" apart. i finally had to use a velcro ski-strap to keep them together during transportation. anyway, remember this photo of Kelvin holding the Kaffeines?
the first run was from the top of Emerald chair down a groomed blue run. i wanted to have a chance to feel them before taking them on steeper and more varied terrain. the first half of the run i keep my heels down and drove them alpine style. the first thing i noticed was they had a smaller "sweet" spot than most skis i've been on. i had to stay more balanced over the skis to get them to turn. after ten turns or so i felt comfortable, but the skis definitely needed some attention. i noticed they weren't very comfortable going straight. they were happy on edge, turning, and with active pressure applied (most likely to "de-activate" the effects of the camber). but even during the turn they needed attention. i think Kaffeine is a good name for them because they definitely kept me awake...at all times. a few turns later i decided to let them run but still with my heels fixed. i was able to push them and they carved beautifully, but with attention of course.
for the second half of the run, i decided to tele turn them. the camber seemed to make them feel a bit awkward. at first they wanted to resist the style of turning, but with i found a balance and pressure point to get them to behave. again, they didn't not like going straight. i had to keep them turning.
my thoughts after the first run: a great ski, in terms of the turning radius, dampness, and stiffness. and when they behaved, they were great! (Kelvin, i think we have a winner here, modulo the camber). the only thing i didn't like was they felt a bit unpredictable. sometimes they had a mind of their own and would track off trajectory. turn initiation need some effort at times.
next, i took them into soft snow and varied terrain. they skied the 6-12" of powder that we found great, as long as i kept them turning. when i relaxed and tried to make more gentle turns, they wanted to submarine and run off. here's a video that Chris Cass made with his small point-and-shoot camera.
http://www.skibuilders.com/gallery/kaff ... istler.wmv
for whatever reason, on more or less flat terrain like cat-tracks and traverses, the Kaffeines were so slow. i wonder if the camber has any affect. i struggled to keep them moving when the terrain eased off. they skis were freshly waxed.
at half-day, i switched over to the Stiff Upper Lips. this is pretty much the same ski. i immediately noticed how easy they were to turn; they were significantly more predictable and fun to ski. i didn't use as much energy to keep them under control; i didn't have to "fight" as much compared to the Kaffeines. however, i did notice that the Stiffs were not quite as "positive" as the Kaffeines in terms of carving on hard snow. i almost want to say that i like the feel of the Kaffeines better (except the camber); they felt more solid. but the Stiffs were more forgiving. i wonder if it's related to the camber or the location of the titanal or both? as for gluiding abilities on traverses and cat-tracks, the Stiffs were great. in contrast, the Kaffeines were slow for whatever reason...
in summary, between low and high camber, i think low camber skis are more user friendly. they feel more predictable. in terms of skiing in powder, based on my experience, high-camber skis tend to submarine when they are not actively turning. i got into trouble when i was trying to straight-run or when i was trying to make more gentle turns (applying less pressure). again, i found they were slow too on flat stuff - i'm not sure if this is a camber-related issue.
the next thing to try is a soft ski with lots of camber....
Henrik wrote:No I can not bend them together but what I mean is that the skis will bend this much and not break!
What I did is that I placed one ski in a deep ditch with an angle of ~60 degrees in the bottom and, this was hard to my heart, jumped on it. The ski was standing like an U but they did not even give a sound of that I was reaching the break point. This day it was more than 30 degrees celsius in the shadow and you should not perform these tests when hot as glass fiber is much stronger when cold!
And about carbon, it is not very good in taking compression!
Henrik
Professor!
If I remember well, camber is used to keep pressure on the edges from tip to tail. This is something you need if do World Cup slalom turns. For everyday skiing, having less pressure on the tip and tail, make easier to turn the skis, and it makes much easier to make sliding turns.
In powder there is no need for pressure along the edges, so flat or even negative camber skis work great. Actually a ski with too much camber and too stiff is useless in the powder. The ski turns in the powder only if it is bent to a negative camber and you can not bent ski that is too stiff (or with too much camber) just because the soft snow is not applying enough pressure to the ski base. I suppose that a very stiff ski with 10mm camber is a nightmare in powder, while the same skis with 10mm negative camber would be just wonderful.
By the way, if you go back to the groomed with a negative camber ski, you can still enjoy it: the contact length between the edges and the snow is reduced to maybe 1 meter. It is enough to have some fun (think about bigfoot, snowblades), but it is not something you would choose to compete against Hermann Mayer.
What do you think?
In powder there is no need for pressure along the edges, so flat or even negative camber skis work great. Actually a ski with too much camber and too stiff is useless in the powder. The ski turns in the powder only if it is bent to a negative camber and you can not bent ski that is too stiff (or with too much camber) just because the soft snow is not applying enough pressure to the ski base. I suppose that a very stiff ski with 10mm camber is a nightmare in powder, while the same skis with 10mm negative camber would be just wonderful.
By the way, if you go back to the groomed with a negative camber ski, you can still enjoy it: the contact length between the edges and the snow is reduced to maybe 1 meter. It is enough to have some fun (think about bigfoot, snowblades), but it is not something you would choose to compete against Hermann Mayer.
What do you think?