Asymmetrical layup in Snowboards

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Minga
Posts: 42
Joined: Tue Dec 16, 2014 2:05 pm

Asymmetrical layup in Snowboards

Post by Minga »

It is pretty common to find asymmetrical glasfiber layups in Snowboards, e.g. Triax on top and Biax on bottom. If you just do it like that you normally end up with concave base in a heat cure. I wanted bounce some ideas and possible tricks with you guys to prevent that. Two possibilites came to my mind so far.
1. Make a convex mold so that the final Board cools down to a flat one.
Possible disadvantage is of course that your cattrack does not adapt to it and you end up with uneven Pressure. As most people and companies seem to use catracks this is probably not the way to go.

2. Lower the wheight of the +45/-45 fibers until their is no warp anymore(in a biax/triax Setting). But this also lowers the torsional effect of the triax weave which is the reason to use it in first place. And although i havnt carried out the computations i would suggest that the resulting torsional stiffness is not better than in the biax/biax setting.

Anymore suggestions or insights on this topic? How do the big guys do it?

Cheers,
Hannes
gav wa
Posts: 381
Joined: Tue Feb 18, 2014 8:58 pm
Location: Perth

Post by gav wa »

If you get your laying up sorted and your resin curing worked out you don't need anything fancy.
I've been doing mixed up layups for about the last 10 boards, no difference in flatness. A few tricks to it though, but you can get there. Even with carbon fibre, I'll put carbon fibre on one side not the other, makes no difference.

You could try both those other ideas though. If you get the convex mold sorted you are pretty much the whole way into making spoon shaped tips. Although I have a full 400mm wide bladder in my press and I don't use a cat track but I still haven't gone for a spoon shaped mold. I would have to ride a few before I am convinced it is the business.
A small bit of shape would probably be possible with a wooden cat track and standard hoses though.
Minga
Posts: 42
Joined: Tue Dec 16, 2014 2:05 pm

Post by Minga »

Hm, seems a bit against physics to me :)
Glasfibers extend in heat. In a heated press they thus cure in an extended state. When the board cools down they retract again and if you have more fiber weight on one side than the other this creates stress which leads to a warping. Do you pull your boards hot or let them cool in the press?
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