Failures?

rockaukum · Post by **rockaukum** » Sat Jan 07, 2012 5:28 pm

Okay, I need help. Today my son showed me his skis. Trashed! Now, I expect to see the tops and bases to be beat because he spends his time on the rails and such. However we had a failure with these. It broke on the tail where the core and spacer meet. we did have a problem as the spacer shifted a small amount over the core. I'm fairly certain this (along with his style) was the main cause for failure.
Question one: What method are you guys using to secure the tip spacer to the core durring layup to avoid shifting? I use the double sided carpet tape on the top of the core and am thinking to use it on both sides. Any suggestions?
Next up is edge failure. Certainly due to landing on the rails as the edges crack under foot only mainly right foot inside (dominate foot). I have never had this problem with my skis but My skis stay on the snow and avoid those metal structures!
So what do you guys do about that?
Thanks for any suggestions.
ra

twizzstyle · Post by **twizzstyle** » Sat Jan 07, 2012 8:20 pm

I haven't done anything with my tip spacers, just lots of checking when it's all in the press before inflating the hose. If it slides over I fudge with a popsicle stick until it's right... sucks but it works. Some people staple the tip spacer to the sidewalls, just outside where flashing will be cutoff. I'd like to start doing that, I think that's better than putting tape in there (that prevents epoxy from going everywhere).

As for edges cracking... yep, that happens with park skiing. Nothing you can do to prevent it, aside from de-tempering the edges. But that's kinda silly. Some people have threaded kevlar in the edge tines side-to-side, so that if you do get lots of cracking, at least the edge won't get pulled out. I have old old park skis that have ~3" sections of edge totally missing. Park is just hard on skis

vinman · Post by **vinman** » Sat Jan 07, 2012 9:09 pm

I use paper first aid tape to hold the tip spacers in place. It is very porous and seems to wet out well. I definitely think double sided carpet tape would not wet out at all and would likely be the cause of your delam.

As for the edge problem, the only way to fix that is like tizz said, Kevlar thread or stop sliding rails. Even with that I'm not sure the Kevlar would help with the kind of impacts u get on rails.

rockaukum · Post by **rockaukum** » Sat Jan 07, 2012 11:22 pm

Thanks for the replies. On the issue of the tip spacer, There is no "delam" issue as such. I would say it is a location issue. While moving the layup to the press and sometime durring the initial stages of inflating, the tip spacer rode up a bit onto the core (maybe a 1/16). The tape I use is quite strong and it is not solid so to speak. Think of it as a square grid work of fibers that are sticky. So the epoxy makes good contact with both the wood core and the spacer material.
Can you explain the staple method a little more? Sounds interesting too.
ra

Dr. Delam · Post by **Dr. Delam** » Sun Jan 08, 2012 12:47 am

Staple method is pretty simple and works well. One side of the staple goes into the tip spacer and the other side goes into the sidewall. This is outside of the actual ski where the flash is cutoff.

I usually don't bother and my spacer stays in place well. I also do my layup in the mold so there isn't much opportunity for things to move around.

I have also seen a technique of using super glue. While you are laying up, spread some super glue at the joint of the spacer and core.

I don't think there is much you can do about edges cracking from rails. Mine usually don't rip out but they definitely crack. Plus, they get so rounded out that it doesn't really matter anyway.

Jekul · Post by **Jekul** » Sun Jan 08, 2012 5:22 pm

I've started using sheet rock tape since it resembles (very loosely) a very loose knit FG. I tape both sides.

Also, since the tape doesn't have a ton of stick, I'll glue it with my hot glue gun to give it a little extra. I use the glue on both sides as well.

Richuk · Post by **Richuk** » Mon Jan 16, 2012 1:48 pm

Another option for you Ra - in the middle of setting things up, hence the delay.

Make the piece on the right first - using a table router and a straight edge: https://picasaweb.google.com/1104837200 ... 4278628130

Comes together something like this, you'll want to do it a little differently: https://picasaweb.google.com/1104837200 ... 7629254994

It's a different way of doing what SHIF has outlined in his blog.

bullion mine · Post by **bullion mine** » Tue Jan 17, 2012 7:03 am

I inlay sidewall material into the wood core blank like happy monkey shows on his website so there is wood on the outside of sidewall. then I duct tape the tip and tail material to the wood that is outside the sidewall and gets cut off as flash. I also use a small piece of white athletic tape in the middle of core/tip-tail. I do this top and bottom of ski.

skidesmond · Post by **skidesmond** » Tue Jan 17, 2012 2:35 pm

Well you probably have enough ideas on how to fix the problem, but, I use blue masking tape on the outside of the core and spacer. It gets cut off with the flashing afterwards.

rockaukum · Post by **rockaukum** » Fri Jan 20, 2012 9:57 am

Thanks for the information. To continue on with further questions...
If you are not doing full wrap edges, Are you concerned with where your edges end in relation to the tip spacer as it meets with the core?
My thought is that you want the edge to run past the tip spacer joint in order to help prevent a weak area. So, how much overlap would be sufficient? I don't have any issues with my skis but do with the ones my son is using. A lot of tip / tail abuse due to park riding...
Also, any advancements in helping with edge cracking from riding the rails?
thanks,
ra

skidesmond · Post by **skidesmond** » Fri Jan 20, 2012 10:06 am

I run my edges at least 3.25inches past where the core and tip space meet. But I stay off the rails, etc.

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Failures?

Failures?