Twizz 2012/2013

twizzstyle · Post by **twizzstyle** » Sat Sep 29, 2012 7:24 pm

What's next, you're going to be posting on Newschoolers??

KevyWevy · Post by **KevyWevy** » Sat Sep 29, 2012 9:40 pm

brb

powderho · Post by **powderho** » Sun Sep 30, 2012 6:46 am

Twizz--are you bonding the honeycomb directly to the core at all? Or, are you just bonding it to the veneer and then the veneer to the core? If you wrapped the entire honeycomb piece in a film adhesive before you inserted it into the core you would gain a lot more contact area for bonding. If I understand what you are currently doing correctly, the "walls" of the honeycomb aren't bonding to anything.

twizzstyle · Post by **twizzstyle** » Sun Sep 30, 2012 8:23 am

That's correct the walls aren't bonded to anything. I'll get some pictures up later today.

The delam happens on the top and bottom faces of the honeycomb

skidesmond · Post by **skidesmond** » Sun Sep 30, 2012 10:38 am

I thought of using foam in the honeycomb so you'd have a surface to bond too, but then that defeats the purpose (would make quite the mess as well).

FigmentOriginal · Post by **FigmentOriginal** » Sun Sep 30, 2012 11:33 am

Maybe try a core cutout in the tips like Kastle does on their skiis, then the honeycomb throughout the rest of the ski. Just a thought...

vinman · Post by **vinman** » Sun Sep 30, 2012 12:57 pm

Found this. I did not read it all but a quick read of the abstract made it look promising. Should be right up your ally.

http://www.in-tec.com/news/wp.pdf

twizzstyle · Post by **twizzstyle** » Sun Sep 30, 2012 5:16 pm

Wow thanks Vinman, that was a great read.

One of the biggest things I took from it was the required surface finish of the honeycomb. I cut my honeycomb into slabs on the bandsaw which left a very fuzzy surface. I thought the fuzzies would be great for soaking up resin and forming a good bond. Turns out it's actually the opposite, a fuzzy surface gives you the worst bond with honeycomb.

This said to wet sand the surface with 320 grit to have a perfectly clean face on the honeycomb, and that will give you the best bond. Interesting!

vinman · Post by **vinman** » Sun Sep 30, 2012 5:19 pm

Pretty much the same as with regular wood, a planed surface is better for bonding than a sanded surface. I hope it helps. Good luck, keep us informed.

twizzstyle · Post by **twizzstyle** » Mon Oct 01, 2012 6:17 pm

As promised, some photos of my honeycomb shenanigans last weekend.

The slab I've had sitting around for years

Sliced into 15mm thick slabs

CNC'd out some areas to put the honeycomb in

After profiling. Notice the bits that were ripped out at the tips

You can see the fuzzy finish that I thought was goodness, but have now learned is badness for bonding.

And just for fun, I laid out all of my Piggy Sticks from the past few years. Another new version is currently in the works with a very new shape to me, should be pressed in a couple of weeks.

I also mounted the bindings on the "Pinky Sticks" (the skis I made for my wife). Homemade skis always look SO much more serious with bindings mounted.

Just needs to snow!!!

sammer · Post by **sammer** » Mon Oct 01, 2012 7:23 pm

Twiz... are you still doing the same angle on your tip spacers (as on the original piggysticks) or have you moved on to straight across cut?
I can see where your honeycomb deteriorated in the tip and tail with profiling.
I think smaller sections of honeycomb cutout of your core might work.
Is it possible to loose the frizzies?
From what I got from that article I would try smaller areas and forgo the veneer just glass prepreg* for the next trial.
*wetout your triax on a separate table just before layup.

The top sheet pattern is definitely looking good and becoming your trademark!

sam

twizzstyle · Post by **twizzstyle** » Mon Oct 01, 2012 8:59 pm

No I just do straight across on all my tip spacers, I only did the angle on the first few pairs.

That article talked about wetsanding with 320 grit to get rid of the fuzzies, I'll give that a try.

My only reason for doing the veneer is I worry about the honeycomb just filling with epoxy (rather than the epoxy squeezing out like normal) and the skis becoming super heavy. What I should really do is get some of those pre-cured pre-tensions fiberglass sheets.

OAC · Post by **OAC** » Tue Oct 02, 2012 3:50 am

Beehive!

twizzstyle · Post by **twizzstyle** » Tue Oct 02, 2012 7:07 pm

Have you guys seen the foam core Kelvin has for sale on blank slate now?

At $38 per core it's a bit pricey, but looks like nice stuff.

http://www.blankslateskis.com/foam-core ... -x-1854mm/

twizzstyle · Post by **twizzstyle** » Tue Oct 02, 2012 8:53 pm

Templates for the two new pairs we're doing.

(I'm still cutting out the bases with the drag knife on the CNC, but I still like to use the template for bending the edges, and attaching the edges)

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Twizz 2012/2013