Another Critiquing my ski design.

sweaterskier · Post by **sweaterskier** » Thu Jun 16, 2011 6:47 pm

First time creating a ski, kind of doing a new idea i have. let me know what you all think.

dims. 186cm. 133/112/130mm running length 141, and tip and tail rocker 25/20cm

Materials.

Isospeed 7200 Black p-tex base, Triaxial braided fiberglass 22oz, trying to find thick edges any help would be nice there. and ipe wood for core/topsheet. This is where i would like some feedback, I want to try using one piece of ipe for the core, topsheet and sidewalls.

core thickness 2 tip 11 midfoot 2.5 tail.

sweaterskier · Post by **sweaterskier** » Thu Jun 16, 2011 7:58 pm

http://i52.tinypic.com/ua79z.jpg link to snocad design of ski

Richuk · Post by **Richuk** » Fri Jun 17, 2011 2:34 am

It is always helpful to know the weight of the rider, local conditions, type of ski you want to build and what feedback you want.

vinman · Post by **vinman** » Fri Jun 17, 2011 4:22 am

Some folks are stiffening up the tips of rockered skis to keep them from flopping around too much. My tradition camber design was 2-10.-2.2 and I felt the tip was too soft. I like stiff skis though. For my next ski they will have rocker and I'm planning 2.3 in the tip 11 and 2.2 in the tail.

This design will have a 40 cm 70 mm rise rocker tip, 4 mm positive camber and 30 cm rocker tail with 45 mm rise. This design will also have reverse side cut at the tip and tail and traditional sidecut along the running length. Sort of a mix between the rossi s7 and the armada JJ.

If you look at how Volkl makes their rockered skis they stiffen the tip and then progressively soften the waist and tail. I skied the Katana last year and was very impressed with it.

sweaterskier · Post by **sweaterskier** » Fri Jun 17, 2011 4:42 am

Im a fan of soft skis, love em. and for info on me live in vt ski jay, 6 1 in height and 170 and i know the size of ski is fine for me. just trying to see if i dont add a top layer of glass and topsheet will work for this idea, and any feed back on shape and all the specs will be nice. oh also the camber under foot will be 1 mm tip and tail 45 /40.

vinman · Post by **vinman** » Fri Jun 17, 2011 6:06 am

I'm also in VT, ski at Smuggs. I live just south of you.

SHIF · Post by **SHIF** » Fri Jun 17, 2011 8:16 am

sweaterskier wrote:...and ipe wood for core/topsheet. This is where i would like some feedback, I want to try using one piece of ipe for the core, topsheet and sidewalls.

core thickness 2 tip 11 midfoot 2.5 tail.

Ipe is very dense wood and using it for an entire core will result is a very heavy ski that is way too stiff, for powder anyway. I suggest using it strictly for sidewalls and using softer, lighter materials for the core. Consider poplar or bamboo (vert lam flooring). Then use a wood veneer for the topsheet if that's the look you seek.

Relative hardness of various wood species:
http://en.wikipedia.org/wiki/Janka_hardness_test

-S

sweaterskier · Post by **sweaterskier** » Fri Jun 17, 2011 9:35 am

What im going for is to have the core and topsheet be the same, with a wood that does not need to be treated. this is why i picked ipe wood, and i was thinking if there is no topsheet and another layer of fiberglass it would keep it a little lighter as well softer. just thinking here if this wont work just let me know.

MontuckyMadman · Post by **MontuckyMadman** » Fri Jun 17, 2011 10:58 am

You run the risk of damage to the composite without a topsheet as well as potential breakdown of the epoxy due to long term UV exposure.

SHIF · Post by **SHIF** » Fri Jun 17, 2011 12:47 pm

Here is a web site offering skis with a similar construction to what you are considering:
http://www.lightningboards.com/newskisgif.htm

They have P-tex bases but not steel edges. They have plastic edges!, like that's gonna withstand a rock hit.

Go ahead and build your concept, then report back here on how well it goes.

-S

OAC · Post by **OAC** » Fri Jun 17, 2011 1:40 pm

MontuckyMadman wrote:You run the risk of damage to the composite without a topsheet as well as potential breakdown of the epoxy due to long term UV exposure.

Very true! But I'm more concerned about the finish! Just epoxy on top is ugly, IMO.

sweaterskier · Post by **sweaterskier** » Fri Jun 17, 2011 1:55 pm

MontuckyMadman wrote:You run the risk of damage to the composite without a topsheet as well as potential breakdown of the epoxy due to long term UV exposure.

I'm looking for a water resistant wood that would keep the composites dry. That is also why a little bit harder wood as well to get the uv from soaking through. As it goes for epoxy couldnt i get away with just putting on bottom and leaving the top clean? seeing how nothing is going to be on it there is no need to epoxy that side.

OAC · Post by **OAC** » Fri Jun 17, 2011 2:24 pm

In my world it's the other way around: The composite will keep the wood dry. Sort of....
Maple and poplar will do the job for you. In my latest cores I skip the maple inside and just use it for the sidewalls(keep the weight down). Maple is enough water resistant(in it self) for lasting a couple of seasons. If you don't store them in a pool...

.
My next cores will be with fir or spruce(for the same reason). I would love to get some paulownia, but it seems difficult to get here.
Don't overdoing it the first time. Ski building is all about try, try, try, test, test, test....

skidesmond · Post by **skidesmond** » Fri Jun 17, 2011 2:27 pm

The epoxy can soak through veneer. Veneer is very thin around 1/42inch. You can get thicker veneers up to 1/16inch from http://www.certainlywood.com/ in NY.

I was just looking at a web site of a guy who makes skis and only uses composites on the bottom of the core, sounds like you want to do the same. I'm sure I found the web site in this forum just a couple days ago.....

I still think you need some kind of protection on the top and sidewalls whether it's poly, tung oil or boiled linseed oil. If moisture seeps in it can cause delams.

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