Ski Builders Forum

Brazen wrote:Which way camber changes?!? Will the sidewalls BULGE OUT 12º? 60mm tip reverse camber and -25mm middle with a -30mm tail?!? Will the top and bottom temperature make a difference!?! I have to know!

I just get a little tired of the nebulous crud in here sometimes.

Oh, so now you want specifics????? LOL

You probably already know this, but due to different thermal expansion and contraction you want the same material on top and bottom of your laminate. Adding carbon only to the bottom will drastically increase your camber. Adding it only to the top will drastically decrease your camber.

If you'r using biaxal carbon and only have it in the center on the bottom you will increase your camber and give yourself an edge high base. Uni won't give you an edge high base if laid in the lengthwise direction, etc. etc... etc..

Of course this is assuming that you're using heat, which I guess the op might not be using.

hahaha okay stinker. Thanks Sheesh, and you so got me. I'll stop hinting at stuff now.

So if I am not using heat then i wont have to worry about camber changes?

Kingswood only puts CF on top of the core.
http://vimeo.com/11793783

Drew wrote:So if I am not using heat then i wont have to worry about camber changes?

Kingswood only puts CF on top of the core.
http://vimeo.com/11793783

As far as I know you shouldn't have to worry about it without heat. YMMV however.

ON3P also puts carbon on top only. Depends on the weight and weave, how much it will affect camber. You can counteract the effect by building more or less camber in to the mold, or offsetting the heat between top and bottom blanket.

And I apologize. The new CNC cutter is doing just whatever the hell it decides it wants to and I'm just sick right now. Sorry.

you're all good Brazen. I think I'm starting to get you.

Kingswood don't use any heat in their press.

My latest pair I put uni carbon 50mm width under the core only.
I have baked them bottoms up in the sun and they seem to have developed some camber (actually not a bad thing because it will make them how I would rather this design be with a small amount of camber under foot rather than flat). The original pair had carbon above core and seems to be a little reverse cambered. No heat, west system epoxy.

I think moment use carbon under the core only and use heat
ON3P use it above the core with heat

I think I get brazen too - he thought where it said "forum" it actually said "four rums"! But I like his input!

My main question still stands, would adding a 3" carbon strip above or above and bellow the core have a significant effect on stiffness?

Drew wrote:My main question still stands, would adding a 3" carbon strip above or above and bellow the core have a significant effect on stiffness?

yes.

Thanks Montucky.


Second ski going in the press in a couple hours.

What if I added a 3" strip of Carbon on top of an already pressed soft ski?

Skis are complete and are way too soft in the tip and tail. If I added a Carbon strip from binding to tip and binding to tail would I get the same effect?

AK, I don't think so but you may notice a slight difference.
You want the uni composite structure in a compression situation to run the full length to get the maximum benefit.

Yeah you might get a slight increase in stiffness, but since ski stiffness is felt mostly when the ski is flexing upwards, you want the carbon on the bottom side of the core (so that it's in tension).

You could glue on some vertical ribs of thin plywood (seriously)

Ski is in the press. I had to wait because it has been cold for the past week and I wanted it to be 50degrees before I put them in the press. It is currently 50degrees in my shop so I laid them up.
I experimented on this pair and used an aluminum topsheet since the previous pair was too soft.

Hey Drew, tune into what Twizz is saying.

Stiffness comes from the shape of the core, but if it is just wood and GF, then the wood will tire over time. If you are using CF to focus the performance of the ski, then putting it in the top layer will delay the interaction of the CF until the support provided by the top layer is engaged. So, if the core provides stiffness, you won't feel the benefit of the CF directly if placed on the top, until the core has been flexed hard. If the core is soft, the CF will be felt earlier, because the core is always being flexed. I believe the opposite is true for CF on the bottom layer - it is engaged immediately, depending on the length of CF placed within the core.

This is just my 2 cents and I hope you get good results! All adds to the mix