Search found 128 matches

by SleepingAwake
Thu Sep 19, 2019 3:56 am
Forum: Ski/Snowboard Design and Layup
Topic: Need help with kid snowboard
Replies: 13
Views: 182

Re: Need help with kid snowboard

I would love to share the spreadsheet, but cannot because it is an adapted work thing. But it is just based on sandwich theory and basic mechanics and for sandwich panels we get within 1 to 2 percent of the calculated stiffness.
by SleepingAwake
Thu Sep 12, 2019 1:08 am
Forum: Ski/Snowboard Design and Layup
Topic: Need help with kid snowboard
Replies: 13
Views: 182

Re: Need help with kid snowboard

Aha thanks chrismp for the clarification. this is what i had in mind actually using a unbalanced fabric with more fibers running in 0°
flex.PNG
flex.PNG (27.9 KiB) Viewed 94 times
this where i'm at right now. I'll keep you guys posted on the progress.
by SleepingAwake
Wed Sep 11, 2019 4:35 am
Forum: Ski/Snowboard Design and Layup
Topic: Need help with kid snowboard
Replies: 13
Views: 182

Re: Need help with kid snowboard

thank you guys for the inputs. I'm rather fit with the nerdy stuff and i ran some numbers and with the 1/3 stiffness approach and a light-ish glass layup and a Bcore balsa core that i use in my skis i still get a reasonable core thickness. otherwise i would increase the core thickness locally in the...
by SleepingAwake
Fri Sep 06, 2019 12:03 am
Forum: Ski/Snowboard Design and Layup
Topic: Need help with kid snowboard
Replies: 13
Views: 182

Re: Need help with kid snowboard

Yeah that was my gut feeling too. What do you think about the layup? I might just end up making a board 1/3 of the stiffness of an adult board for 1/3 of the rider weight. Kind of makes sense i guess? Even tho the surface area of a kids board is more than 1/3 of an adult one so not quite convinced i...
by SleepingAwake
Thu Sep 05, 2019 5:20 am
Forum: Ski/Snowboard Design and Layup
Topic: Need help with kid snowboard
Replies: 13
Views: 182

Need help with kid snowboard

Hey Guys I'm a skier myself and built quite a few skis and know what i do there. But i would love to make a snowboard for my niece as a christmas gift and need some pointers as i have no clue how stiff a snowboard for a 8 year old girl should be. Anyone who can give me a starting point with a core t...
by SleepingAwake
Wed Nov 14, 2018 11:29 pm
Forum: Ski/Snowboard Design and Layup
Topic: Lay up sequence - carbon next to wood
Replies: 7
Views: 1189

Was curious of how much it would change a quickly ran the numbers. for a pure carbon layup: the tip is about 11% stiffer when diagonal layers are facing the core the center is about 3% stiffer when diagonal layers are facing the core The difference is bigger with flax on the diagonals as due to the ...
by SleepingAwake
Fri Nov 09, 2018 7:10 am
Forum: Ski/Snowboard Design and Layup
Topic: Lay up sequence - carbon next to wood
Replies: 7
Views: 1189

I have seen plenty of problems with carbon directly on wood. If you need to do this then use a thin glass or polyester fleece inbetween to give a tougher interface. The problem is the huge difference in stiffness that creates big shear stresses at the interface. For the same reason the diagonal laye...
by SleepingAwake
Fri Mar 23, 2018 9:25 am
Forum: Ski/Snowboard Design and Layup
Topic: Why not completely replace fiberglass with carbon?
Replies: 7
Views: 2462

Re: Why not completely replace fiberglass with carbon?

As far as I understood, carbon young modulus is 3 times greater, than fiberglass. So 3 times less is needed, to get the same stiffness. Tension strength overpowers for typical ski tension forces for both materials. So, what are reasons (except price) to use fiberglass? The problem with that is, tha...
by SleepingAwake
Tue Dec 12, 2017 12:23 am
Forum: Materials and Supplies
Topic: fiberglass and carbon proportions O_O!
Replies: 66
Views: 25467

Thanks for the reply SA. Well, I already have the carbon and glass so I’ll take another look at this. I have 20 and 22 oz triax as well so I can mix and match and come up with something Just curious what you were comparing to my layup to? Cheers, Bill I compared it to my freetourer with similar d...
by SleepingAwake
Mon Dec 11, 2017 8:05 am
Forum: Materials and Supplies
Topic: fiberglass and carbon proportions O_O!
Replies: 66
Views: 25467

I made some quick calculations based on your info and compared it to my go to flex profile. The numbers are not overly precise but should be close enough (unless you planed to use high modulus carbon...) The tip is 16% stiffer than mine, the center is 60% stiffer than mine and your tail is 15% less ...
by SleepingAwake
Tue Oct 31, 2017 7:29 am
Forum: Journals: Log Your Ski Building Progress
Topic: Back and looking forward to building!
Replies: 22
Views: 5145

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 differen...
by SleepingAwake
Sun Oct 29, 2017 9:01 am
Forum: Journals: Log Your Ski Building Progress
Topic: Back and looking forward to building!
Replies: 22
Views: 5145

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...
by SleepingAwake
Wed Oct 25, 2017 6:56 am
Forum: Journals: Log Your Ski Building Progress
Topic: Back and looking forward to building!
Replies: 22
Views: 5145

doughboyshredder wrote:Also want to point out that I'm looking at pre cured not pre preg. Fully cured sheets.
This is why I wrote that sanding dust is probably more problematic and I personally would rather use a flax laminate with liquid epoxy rather than having to sand the precured glass.
by SleepingAwake
Sun Oct 22, 2017 10:51 am
Forum: Journals: Log Your Ski Building Progress
Topic: Back and looking forward to building!
Replies: 22
Views: 5145

Some cool ideas coming out simply by someone wanting to try somethung different, that's cool. I would email the info desk at Henkel, they have always really gone out of their way when i have had a question for them. They might have a VOC free option. I have always thought that VOC free epoxy had a ...
by SleepingAwake
Sat Oct 21, 2017 1:53 am
Forum: Journals: Log Your Ski Building Progress
Topic: Back and looking forward to building!
Replies: 22
Views: 5145

Hey guys I work quite a bit with entropy resins, and while I generally like their products a lot I would like to point out that it is still an epoxy and the source of the raw materials doesn't mean it's any better for your health. But with proper handling epoxies are really pretty safe to use and gl...