Ski Builders Forum

I have one ski in the press now its my first ski I have built snowboards before my only worry is the base might shift I taped it down. I used the nail idea the keep my core strait. and I hope its stiff enough
LAYUP
topsheet
9.8oz 0 90 biax carbon
10.5mm ash/poplar core
9.8oz 0 90 biax carbon
2 pieces of 45 -45 biax carbon tape along the edges
base

very interesting. Hope you have some rubber in there.

My understanding was the 90 in composites for skis does nothing. But Im wrong just about every day so...
Can't wait to see pics.

I cant post links to pics yet as I am new so when I can I will

I am waiting for my buddy to finish this ski and lay up the other one

I heard the same thing about the 90 for skis but in snowboards you need it and the skis are 142 112 132 so the 90 cant hurt. with carbon there is more torsional stiffness in the uni so if I add 90 to the 0 there should be more torsional stiffness in the hole ski well it make sense to me

http://www.facebook.com/album.php?aid=2 ... =fbx_album





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sorry they take you to the same place

90 won't help with torsional stiffness at all. For torsion you want the fibers running at an angle (45 deg). When twisting, all loading occurs in sheer.

If you have something rubber (like a rubber eraser) draw some lines on it, and then twist it by hand. You'll see how the lines skew in sheer.

Or, here's another way to look at it. Do you have a cattrack? Pretend a cattrack is carbon fibers running at 90. If you twist the whole thing, does any load get taken up in the bars? nope.

The 90 deg fibers are only going to stiffen it laterally, which like you said probably matters on a snowboard, but on even a wide ski it will make negligible difference. (Who told you with carbon there is more torsional stiffness with uni?? More than a triax? Not the case) But like you said, certainly no harm in having the fibers there

Congrats on your first ski!!!!

Interesting reinforcement on the edges, I've thought about something like that underfoot to help keep edges in when they get trashed on rails, but with kevlar.

yea a lot of my friends edges tear out at the tips and tail and waist so I used the strands that came off the carbon I cut. kevlar would prob be better.

And I was told that carbon didnt have much torsional stiffness but what it had was better then fiber glass

You may be right about carbon's torsional stiffness being higher than glass, but either way it's so minimal it's essentially irrelevant. You want the fibres of any composite material running in the direction you want to reinforce, which is why 45/-45 or 60/-60 is so common in boards and skis. Glass running at 45/-45 or 60/-60 will be a hell of a lot stiffer torsionally than carbon at 0/90.

Having said that, there is such a thing as too stiff, and as always ski building is more of an art than a science. If they are good fun to ski on that's all that really matters in the end.

it will be awhile but when he test them I will tell yous how he said they rode it is a pow ski so I want it to be like a medium stiff ski so thats why I used 45-45 tape to help along the edges there is a space about 2" apart at the widest part (tip) of the ski between the tape. all I can do is hope it rides good for him it feels good about right were I wanted. but I dont ski so I hope he likes them.

thanks for the info guys

one ski done here are the pics


http://www.facebook.com/photo.php?pid=6 ... 1726202328

Am I the only one who gets this message from Facebook whenever someone posts a FB link in here?!?
I'd love to have a look, but it doesn't work for me.

photobucket?