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Ripped up my latest build

Posted: Mon Aug 09, 2021 2:08 pm
by Jdline
So i just ripped my latest build apart to see how the inside looks like.

Its a beech en pauwlina core, flax en carbon lay up, and a oak wood veneer topsheet.
I put the ski in a buckle and started bending it till it broke.
I did not expect the core to brake so soon ( about 60°)

Not enough epoxy on the flax it seems.
And not a good bond between the carbon and the core,also not enough epoxy?

What are you guys' thoughts?
https://ibb.co/7pBk0v7
https://ibb.co/Qp3SVjy
https://ibb.co/j87nJBQ
https://ibb.co/WcCZk7L

Re: Ripped up my latest build

Posted: Wed Dec 15, 2021 8:04 pm
by ianrice
Did you break this just to gauge what could be done with the next one, or did they blow out in some other way first?

I haven't made my first pair just yet so I can't offer any constructive thoughts here. Looks well built overall, though. Interested to see what you come up with for other failure reasons.

Re: Ripped up my latest build

Posted: Thu Dec 16, 2021 8:44 am
by SHIF
What epoxy did you use to build this with? It looks very dry inside. I couldn't pull any of my skis apart like this, can't even peel off the top sheet. I've used QCM and also Resin Research epoxies, never had an issue when skiing.

Re: Ripped up my latest build

Posted: Mon Dec 27, 2021 9:55 am
by 24Dave
In the last picture it looks like the resin barely penetrated the paulownia and like it hardly touched the beech wood. It appears like the wood was oiled or something to prevent the epoxy from bonding. Was epoxy coated on the wood before laying the carbon fabric down? I would not use that epoxy again.

Re: Ripped up my latest build

Posted: Mon Dec 27, 2021 2:33 pm
by Jdline
the core was not oild, it was sanded down to profile.
sanded to fine?

I put some serious strength into breaking them.
The epoxy was from a local supplier, but i have already changed to another, that feels much better.

I had put to much camber on the ski so it was rubbish anyway, so i broke it to see how good ( better, BAD) it was.

On the next skis i have put more epoxy on them, making sure that it is wet