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#11
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Modify/stiffen your own skis?
On Apr 1, 5:14*pm, wrote:
I would think if you wanted to soften a ski functionally, you could broaden the flex range in the middle toward the tip and tail by some careful scraping. rm The bigger question nobody asked is why screw around with a ski that doesn't fit by adding material etc while not knowing what they are doing. Srew up the ski than you can't give it away. Why not just get a new ski that fits? |
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#12
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Modify/stiffen your own skis?
On Apr 2, 12:37 am, wrote:
On Apr 1, 5:14 pm, wrote: I would think if you wanted to soften a ski functionally, you could broaden the flex range in the middle toward the tip and tail by some careful scraping. rm The bigger question nobody asked is why screw around with a ski that doesn't fit by adding material etc while not knowing what they are doing. Srew up the ski than you can't give it away. Why not just get a new ski that fits? Wahhl, for those with experience and who have done some testing, why not? There are lots of old skis to experiment with. Most elite hobbyists customize their stuff. Skiers are the few I've seen who don't usually monkey with their stuff. The base doesn't affect stiffness, I don't think. So, sure they wax and grind the base, but one might find that with a bit of testing that FOR FREE you can TOTALLY DIAL IN your skis to be just the way you want them. Trial and error will surely tell you more than off the shelf squeezes and measurements can---altho I suppose some shops can give you lots more data than others---do you always know what that data will mean on the snow?? I mean, you could get it wrong somewhere---so why not learn how to adjust it after you get home? Just because some skiers are not handy doesn't mean they all aren't. And just because some skiers don't really know what they like in a ski doesn't mean others don't. Anyway: thin carbon or glass and a very thin coat of epoxy just might give you stiffness where you want it. Why not try to learn about such things? Offhand I think that skis are thin and weak enough as it is that I don't presume to guess how one might effectively and safely SOFTEN flex somewhere. Maybe one could sand away some of that surface 1mm and replace it with an equally strong epoxy which is flexible. --JP |
#13
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Modify/stiffen your own skis?
On Apr 2, 9:59 am, jeff potter wrote:
On Apr 2, 12:37 am, wrote: On Apr 1, 5:14 pm, wrote: I would think if you wanted to soften a ski functionally, you could broaden the flex range in the middle toward the tip and tail by some careful scraping. rm The bigger question nobody asked is why screw around with a ski that doesn't fit by adding material etc while not knowing what they are doing. Srew up the ski than you can't give it away. Why not just get a new ski that fits? Wahhl, for those with experience and who have done some testing, why not? There are lots of old skis to experiment with. Most elite hobbyists customize their stuff. Skiers are the few I've seen who don't usually monkey with their stuff. The base doesn't affect stiffness, I don't think. So, sure they wax and grind the base, but one might find that with a bit of testing that FOR FREE you can TOTALLY DIAL IN your skis to be just the way you want them. Trial and error will surely tell you more than off the shelf squeezes and measurements can---altho I suppose some shops can give you lots more data than others---do you always know what that data will mean on the snow?? I mean, you could get it wrong somewhere---so why not learn how to adjust it after you get home? Just because some skiers are not handy doesn't mean they all aren't. And just because some skiers don't really know what they like in a ski doesn't mean others don't. Anyway: thin carbon or glass and a very thin coat of epoxy just might give you stiffness where you want it. Why not try to learn about such things? Offhand I think that skis are thin and weak enough as it is that I don't presume to guess how one might effectively and safely SOFTEN flex somewhere. Maybe one could sand away some of that surface 1mm and replace it with an equally strong epoxy which is flexible. --JP Fair enough, but why not start from scratch? A mold for a nordic ski isn't going to be too terribly hard to build, and while optimizing the composite layup isn't trivial it isn't really hard either. |
#14
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Modify/stiffen your own skis?
On Apr 6, 2:03*pm, wrote:
On Apr 2, 9:59 am, jeff potter wrote: On Apr 2, 12:37 am, wrote: On Apr 1, 5:14 pm, wrote: I would think if you wanted to soften a ski functionally, you could broaden the flex range in the middle toward the tip and tail by some careful scraping. rm The bigger question nobody asked is why screw around with a ski that doesn't fit by adding material etc while not knowing what they are doing. *Srew up the ski than you can't give it away. *Why not just get a new ski that fits? Wahhl, for those with experience and who have done some testing, why not? There are lots of old skis to experiment with. Most elite hobbyists customize their stuff. Skiers are the few I've seen who don't usually monkey with their stuff. The base doesn't affect stiffness, I don't think. So, sure they wax and grind the base, but one might find that with a bit of testing that FOR FREE you can TOTALLY DIAL IN your skis to be just the way you want them. Trial and error will surely tell you more than off the shelf squeezes and measurements can---altho I suppose some shops can give you lots more data than others---do you always know what that data will mean on the snow?? I mean, you could get it wrong somewhere---so why not learn how to adjust it after you get home? Just because some skiers are not handy doesn't mean they all aren't. And just because some skiers don't really know what they like in a ski doesn't mean others don't. Anyway: thin carbon or glass and a very thin coat of epoxy just might give you stiffness where you want it. Why not try to learn about such things? Offhand I think that skis are thin and weak enough as it is that I don't presume to guess how one might effectively and safely SOFTEN flex somewhere. Maybe one could sand away some of that surface 1mm and replace it with an equally strong epoxy which is flexible. --JP Fair enough, but why not start from scratch? *A mold for a nordic ski isn't going to be too terribly hard to build, and while optimizing the composite layup isn't trivial it isn't really hard either.- Hide quoted text - - Show quoted text - Well, starting the production work from scratch, building the mold and doing the composite layup, may not be too hard, starting from scratch means having to run a bunch of finite element simulations with a range of elastic and inelastic foundation boundary conditions to simulate the multitude of snow conditions. That said, I guess Jeff would likely use a trial and error experimental appoach to avoid running mathematical model simulations. |
#15
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Modify/stiffen your own skis?
On Apr 6, 8:28 pm, wrote:
On Apr 6, 2:03 pm, wrote: On Apr 2, 9:59 am, jeff potter wrote: On Apr 2, 12:37 am, wrote: On Apr 1, 5:14 pm, wrote: I would think if you wanted to soften a ski functionally, you could broaden the flex range in the middle toward the tip and tail by some careful scraping. rm The bigger question nobody asked is why screw around with a ski that doesn't fit by adding material etc while not knowing what they are doing. Srew up the ski than you can't give it away. Why not just get a new ski that fits? Wahhl, for those with experience and who have done some testing, why not? There are lots of old skis to experiment with. Most elite hobbyists customize their stuff. Skiers are the few I've seen who don't usually monkey with their stuff. The base doesn't affect stiffness, I don't think. So, sure they wax and grind the base, but one might find that with a bit of testing that FOR FREE you can TOTALLY DIAL IN your skis to be just the way you want them. Trial and error will surely tell you more than off the shelf squeezes and measurements can---altho I suppose some shops can give you lots more data than others---do you always know what that data will mean on the snow?? I mean, you could get it wrong somewhere---so why not learn how to adjust it after you get home? Just because some skiers are not handy doesn't mean they all aren't. And just because some skiers don't really know what they like in a ski doesn't mean others don't. Anyway: thin carbon or glass and a very thin coat of epoxy just might give you stiffness where you want it. Why not try to learn about such things? Offhand I think that skis are thin and weak enough as it is that I don't presume to guess how one might effectively and safely SOFTEN flex somewhere. Maybe one could sand away some of that surface 1mm and replace it with an equally strong epoxy which is flexible. --JP Fair enough, but why not start from scratch? A mold for a nordic ski isn't going to be too terribly hard to build, and while optimizing the composite layup isn't trivial it isn't really hard either.- Hide quoted text - - Show quoted text - Well, starting the production work from scratch, building the mold and doing the composite layup, may not be too hard, starting from scratch means having to run a bunch of finite element simulations with a range of elastic and inelastic foundation boundary conditions to simulate the multitude of snow conditions. That said, I guess Jeff would likely use a trial and error experimental appoach to avoid running mathematical model simulations. You could use FEA, although you don't really need to. The deformation of the ski is easy to solve analytically. You would need an iterative solver for the contact boundary condition, but even that's not very hard. The only tricky part is setting discrete constraints for the optimization script. A day or so of coding could save a year of trial and error. That's the hard way of doing the design. The easy way is to start with the layup schedule for a ski that's close to what you want (it helps if you know someone who's broken one) and go from there. |
#16
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Modify/stiffen your own skis?
I've always thought that adjustable stiffness would be posible and a good idea. If someone is to start a new ski factory, think about it. A mobile carbon upper layer and a rollover (or rollunder) adjustement. More or less like a swimming pool jumping board. |
#17
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Modify/stiffen your own skis?
On Apr 8, 2:35*pm, wrote:
I've always thought that adjustable stiffness would be posible and a good idea. If someone is to start a new ski factory, think about it. A mobile carbon upper layer *and a rollover (or rollunder) adjustement. More or less like a swimming pool jumping board. Yup. Jeff may want to talk to the K2 engineers who were using piezoelectric polymers to alter vibration characteristic of skis. By feeding power into the piezoelectric material Jeff may be able to change the ski's structural properties. I think that K2 was trying the piezoelectric skis in the mid 1990s. |
#18
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Modify/stiffen your own skis?
You guys are funny. I think I'll keep it simple. I'll add a thin layer
of carbon/glass to a test ski to see if it makes it any stiffer in a good way. If it does then I'll have an easy way to make good skis even better if they need a bit of extra stiffness somewhere. --JP |
#19
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Modify/stiffen your own skis?
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#20
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Quote:
But putting layers on the top of your ski won't change the stiffness much at all. All the strength of your ski is in the bottom " tension" layer under the ptex. |
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