fiberglass and carbon proportions O_O!

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skidesmond
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Post by skidesmond » Mon Oct 26, 2009 4:38 am

I've always wondered the same.... If you had a blind test of different ski manufacturers w/ skis that were generally the same dimensions if the avg skier could tell the difference (aside of being soft or stiff) whether one ski had a wood core, foam core, fiber glass or carbon, etc.

I thought when the "shape" ski came along it was just another gimmick from the ski industry. Happily I was wrong. However you have to adjust your style of skiing to take full advantage of the ski.

But I've seen a lot of fads come and go.... split tail skis, hole in the ski tip which Fischer has brought back for the racing stock, honeycomb. Remember the groove down the middle of the bottom of the ski? What was that supposed to do? Wonder if that will make a come back.

Determining if a ski is "good" or not seems very subjective. No doubt materials used in the ski make a difference but I've always wondered how much.

Well I hope to press my first set if skis tonight or tomorrow.

twizzstyle
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Post by twizzstyle » Mon Oct 26, 2009 8:28 am

skidesmond wrote:Remember the groove down the middle of the bottom of the ski? What was that supposed to do? Wonder if that will make a come back.
That was actually functional (although before my time...). That was before the use of ground and "structured" p-tex. A completely smooth plastic base would be sticky, you want something to break the surface tension since when skiing, you're really gliding on a very thin layer of liquid water (the friction in the skis melts the top layer of snow). The groove was a way of breaking the surface tension.

Other gimmicks that come to mind - the damping weights K2 puts on some of their skis, or the little oil shocks (these are also functional, but again... how noticable to 99% of skiers?). Or what was the snowboard company that put wavey edges? To help with cutting through ice or something? Right...

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Post by skidesmond » Mon Oct 26, 2009 9:01 am

twizzstyle wrote:
skidesmond wrote:Remember the groove down the middle of the bottom of the ski? What was that supposed to do? Wonder if that will make a come back.
Other gimmicks that come to mind - the damping weights K2 puts on some of their skis, or the little oil shocks (these are also functional, but again... how noticable to 99% of skiers?). Or what was the snowboard company that put wavey edges? To help with cutting through ice or something? Right...
So the groove really did serve a purpose... Yeah I remember that. I think Salomon had built ceramic material into the ski that lit up when the ski vibrated. That was supposed to turn the vibrations into electricity, thereby dampening the ski. Don't see that around anymore.

I just found out about the wavy edge last year from a snowboard instructor I work with. Supposedly it gives more edge contact at certain key points to provide better carvabilty. He thought it made a difference. I was wondering when someone will do that for a ski. I've thought about it, just for grins.

twizzstyle
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Post by twizzstyle » Mon Oct 26, 2009 9:16 am

I thought whatever snowboard company it was that did it, also had a run of skis with the same thing? Can't remember the company though... Libtech?

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Post by twizzstyle » Mon Oct 26, 2009 9:18 am

Yes it was Libtech, and they call it "Magne-Traction"... :?

gketcham
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Post by gketcham » Sun Nov 28, 2010 8:39 pm

has anyone ever used ONLY carbon fiber? Would that make the ski way to stiff? What are the main properties of fiberglass, since CArbon Fiber adds pop and snap?

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Post by PTTR » Mon Jan 28, 2013 2:07 am

This thread is old but interesting!
I only use fiberglass in my ski. And after reading this I think that I will continue to do so. Is the conclusion here that the only thing that Carbon does is to reduce weight?

doughboyshredder, twizzstyle, skidesmond and others, do you have anything to add to this, now 3,5 years later?

Many people in the forum seem to put carbon stringers in their layups, but why?

skidesmond
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Post by skidesmond » Mon Jan 28, 2013 4:19 am

Well, I still have not tried Carbon Fiber yet but many others have. I have run some simple comparison tests between FG and CF. It does reduce weight but adds stiffness and rebound to a ski/board. There are many weaves and weights for CF just like there is for FG. For the most part my skis don't "need" CF because I use mostly hard woods (ash/maple) and 20-22oz triaxial FG, so there's plenty of firmness and torsionally rigidity. But if I was looking to make a lighter ski (thin the core out or use a lighter wood) I would definitely use CF.

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Post by holmtech » Thu Jan 31, 2013 6:27 pm

So I have some triax carbon fiber from Braider that I am wanting to make a good looking all carbon ski with. I was searching for how to get a clean, shiny look to the top layer and ran across this old thread. Interesting posts, so since someone else got it going I'll add my 2 cents.

Twiz, there's possibly a bigger part than friction for the layer of water we glide upon is the fact that as you add pressure to ice the melting point decreases. Also why water expands when it freezes. I believe this is all unique to water. That and the fact that we're usually working close to the melting point (and a little friction) is what we owe to our favorite pastime.

This shows it. For all other common elements, above the split at a very low pressure (.006 atm) both lines surrounding the liquid phase will go up and to the right (increased pressure leads to a solid).
http://serc.carleton.edu/images/researc ... lor.v2.jpg

Good stuff on here regarding the weight savings of carbon adding to "pop" of a ski.

Now has anyone got any tips on how to finish a carbon top ski? My thinking is to layup the top layer of carbon with a healthy amount of epoxy, then carefully (no wrinkles) cover that with parchment paper, then top cassette, and into the press to cook. Add a urethane layer at the end to get a glossy finish.

Any thoughts?

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MontuckyMadman
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Post by MontuckyMadman » Thu Jan 31, 2013 6:51 pm

Clear topsheet.
sammer wrote: I'm still a tang on top guy.

skidesmond
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Post by skidesmond » Fri Feb 01, 2013 4:37 am

I'd skip the parchment myself. I good waxed AL cassette will do the trick. Clear top sheet or poly works.

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Post by vinman » Fri Feb 01, 2013 5:44 am

If you go with parchment, adhere it to your top al sheet with spray adhesive. As the pressure is applied it will add tension to the parchment and prevent wrinkling. If you just lay it on top you'll be risking the parchment sort of slumping into the tip and tail curve....lots of wrinkles.
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Post by Richuk » Fri Feb 01, 2013 7:14 am

For a shiny epoxy topsheet, I think you can use polypropylene or mylar or other such release films. I'm not sure what Huck does, but he does it really well.

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Post by holmtech » Sun Mar 03, 2013 9:18 pm

I was thinking about the clear topsheet. But Huck's board looks awesome. Thanks for the tip Richuk.

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Brazen
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Post by Brazen » Thu Mar 07, 2013 6:30 am

You can use mylar in place of a topsheet in the press, then pull the mylar...comes right off. Leaves a great finish.
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