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SleepingAwake
Posts: 123
Joined: Mon Oct 11, 2010 11:06 pm

Post by SleepingAwake » Sun Oct 29, 2017 9:01 am

doughboyshredder wrote:Ahhh, got it. Are you saying you'd have to sand the sheets before layup, or are you thinking during finishing?
Sry, what I meant is after pressing the ski when trimming off the flash and finishing the sidewalls there is a lot of sanding involved and generally sanding natural fibre composites is soo much nicer than glass.

sammer
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Joined: Wed Dec 19, 2007 10:37 pm
Location: Fernie B.C.
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Post by sammer » Mon Oct 30, 2017 8:26 am

100% solids epoxy usually are 0 VOC's
PU's are generally low VOC's
I think you may have a hard time finding a suitable replacement.

Flax eats a lot of epoxy and this adds to weight as well as more product use.

Pre-cure would still need some sort of glue and would require a lot more grinding, sanding, finishing.

Glad to see you back :-)

sam
You don't even have a legit signature, nothing to reveal who you are and what you do...

Best of luck to you. (uneva)

Gilo
Posts: 62
Joined: Sun Feb 03, 2013 7:36 am
Location: Somerset - the flatlands

Post by Gilo » Tue Oct 31, 2017 2:14 am

hello everyone

can someone explain the mechanics of pre-cure and why you might use it over wet lay up?

thanks

Gilo

SleepingAwake
Posts: 123
Joined: Mon Oct 11, 2010 11:06 pm

Post by SleepingAwake » Tue Oct 31, 2017 7:29 am

the advantages and disadvantages of pre cured laminates i can think of right now are:

+ easy processing with the possibilites of doing precuts of the fibers between the recess from the edges or things like that
+ good consistent fiber alignment and fiber volume fraction
+ Possibility to use different resins (toughened glueing resin) for the bonding between core and laminate.

- limited choice of layups available
- clear layups not really possible as far as i'm aware with commercially available products

I usually work somewhat with precured laminates that i make myself tho under vacuum infusion. This way I have basically all the advantages without the disadvantages as I can make whatever I want. This allows me to have really high quality, void free laminates even tho i press my skis in vacuum.
It's more work tho.

I'm sure i forgot a few things but this should cover the bases

cheers, Reto

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falls
Posts: 1451
Joined: Tue Oct 27, 2009 5:04 pm
Location: Wangaratta, Australia

Post by falls » Tue Oct 31, 2017 10:56 pm

Hey doughboy, welcome back
These guys from Bend are making some slightly different boards
https://www.snoplanks.com/pages/technology
The photos I have seen look like the bamboo cores run full length and are thicker than average. I thought they didn't actually have any glass/carbon in them and used a thicker core to compensate, but it turns out they do have carbon/glass. I think snowoard materials still do a precured layer with carbon strands down the middle and neversummr use something like this in their boards.

There was (is?) the old K2 park ski that had a horizontal laminated core of thin plys that got shorter the higher they went in the ski to create the flex. Much like a skateboard construction. Can't think of the name at the moment but sounds like the bambooyah (and coinceidentally is from K2 as well). Here you go:
Afterbang - https://www.youtube.com/watch?v=WAyFbftIfYw

Paulownia wood is common at the moment esp mixed in with bamboo and is a fast growing plantation tree. Some people who were trying to use the bcomp cores ended up switching to paulownia as weight was still good and bcomp was a bit harder to process.

Bamboo is pretty good as sidewall material also.
Don't wait up, I'm off to kill Summer....

Hannes
Posts: 83
Joined: Wed Nov 09, 2011 2:20 am
Location: NRW, Germany

Post by Hannes » Fri Nov 10, 2017 1:14 pm

I am thinking about building an ecoski as well. I made a pair with biax flax and glass which I really liked. I also liked its dampness. But what about a ski with a full flax laminate? Will it be too damp? Earlybird writes about using carbonstrips. Core would be full ash.

skidesmond
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Post by skidesmond » Fri Nov 10, 2017 7:27 pm

I use full flax and carbon. I use uni carbon about 4-5 ounces. I use a 2inch strip of carbon down the middle. Skis are damp but carbon gives them good rebound. And I use ash for the core.

knightsofnii
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Post by knightsofnii » Mon Dec 11, 2017 1:48 pm

Broz did a lot of precures BITD. He might be of help.

welcome back :)
Doug

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