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Carbon vs Wood made boards

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iriejohn
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Re: Carbon vs Wood made boards

Postby iriejohn » Tue Dec 29, 2020 9:40 pm

iriejohn wrote:
Sun Dec 27, 2020 11:28 pm
Matteo V wrote:
Sun Dec 27, 2020 11:24 pm
iriejohn wrote:
Sun Dec 27, 2020 11:00 pm


I would be very interested to see "the math", would you please share your work sheet(s) here?

Thanks in advance.
Sorry to disappoint, the last one was 11 years ago. But I'll try to PM you when I get back to the "Matteo's Hall of Records" (it sounds nice, though it's actually just a U-haul storage locker).

Are you looking to check my math, or do you disagree with the principle referenced that Kevlar in compression is relative worthless in most composite laminates?
Please post your maths here so that everyone may benefit from your work.

Thanks.
Waiting patiently.

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Re: Carbon vs Wood made boards

Postby Matty V » Tue Dec 29, 2020 10:17 pm

Seems like people are happy to call out others but not so willing to share.. or admit they are wrong. @downunder. How do I have three layer ‘Biax‘carbon?

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Re: Carbon vs Wood made boards

Postby Matteo V » Tue Dec 29, 2020 11:02 pm

iriejohn wrote:
Tue Dec 29, 2020 9:40 pm
Waiting patiently.
The irony is thick with this one. But in the meantime, you should read through that article. Here, I'll give you another link to it:


https://www.google.com/url?sa=t&source= ... 9261659929


And I am sorry for the delay. It just dumped a good ammount of snow on us here. But I will skip the first good snowkiting of the season to go to my storage locker to see if I can find the pair of pants I was wearing 10 years ago that should have that little folded up 2 pages of green engineering paper. Then you should fly over here and we could review it together over a few beers, make any needed corrections, and then publish it here under both of our names.

:out:


Thanks, I needed a laugh after 2hrs of shoveling. Wait....technically I was leaning on the shovel 2.7% of the time at the beginning, and 12.2% by the end. By my calculations, I can only claim I was shoveling for only 1hr and 35 minutes.....wait I forgot to convert minutes to 1/100ths of an hr......and....awe heck, let's just leave it there.

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Re: Carbon vs Wood made boards

Postby Matteo V » Tue Dec 29, 2020 11:17 pm

Oh, and here is a good graphical representation on impact resistance for carbon laminates from that paper.
Screenshot_20201229-160328_Drive.jpg

So I have this idea....can't call it a theory really....But I think maybe you could increase the impact resistance by having a resin rich carbon laminate. Any ideas on that?

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iriejohn
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Re: Carbon vs Wood made boards

Postby iriejohn » Tue Dec 29, 2020 11:55 pm

iriejohn wrote:
Sun Dec 27, 2020 11:28 pm
Matteo V wrote:
Sun Dec 27, 2020 11:24 pm
Sorry to disappoint, the last one was 11 years ago. But I'll try to PM you when I get back to the "Matteo's Hall of Records" (it sounds nice, though it's actually just a U-haul storage locker).

Are you looking to check my math, or do you disagree with the principle referenced that Kevlar in compression is relative worthless in most composite laminates?
Please post your maths here so that everyone may benefit from your work.

Thanks.
Waiting patiently.
Matteo V wrote:
Tue Dec 29, 2020 11:02 pm
iriejohn wrote:
Tue Dec 29, 2020 9:40 pm
Waiting patiently.
The irony is thick with this one. But in the meantime,
True to form you were bullshitting and when called out you can't back off, so you predictably have no alternative but to continue in the same vein. :lol:

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Re: Carbon vs Wood made boards

Postby Matty V » Wed Dec 30, 2020 12:15 am

Yes I rather though the math was done long before you started in this topic, back when you were windsurfing?

Now your recently discovered Gurit page is your go too?

Now start looking at alternate resin systems.. and the effect that has on laminate performance

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Re: Carbon vs Wood made boards

Postby Matteo V » Wed Dec 30, 2020 12:55 am

iriejohn wrote:
Tue Dec 29, 2020 11:55 pm
True to form you were bullshitting and when called out you can't back off, so you predictably have no alternative but to continue in the same vein. :lol:
It is the only "vein" I have! You are asking for a calculation I did a decade ago. Do you honestly think I could provide that documentation to you?

C'mon, irie mon, its the holidays and you and I are both weeding out those brain cells we dont really need via some good drink. So you have an excuse for not comprehending the situation.

But why go on with zero contribution to this thread? And what contribution would my 10year old calculation add here. We can just do it again. And what if my old or new calculation was off by 10 - 20 percent???? Does that mean everything I say is a lie? What if I say the sky is blue and Kevlar is terrible in compression? Are those not true statements even if a parrot is saying them? (Yes, I give you permission to call me a parrot, because we all are as the equations we use were not created by any of us here)

Honestly, I am barely recalling that the information I found when I was having Kevlar compressive failures. I think it told me compressive strength of Kevlar in the layups i was using was like 45 percent of its tensile strength. And now I am reading its 30 - 10 percent of tensile strength??? So now I am even confused! But what I am clear on is when I was using s-glass with a layer of Kevlar to "toughen" the surface against heel dents, the numbers showed it was no better than just the s-glass. And since I am finding out that it seems to be even weaker in compression than the information I had back then.....well, it does not change the decision/realization that calculation gave me.


So once again, happy holidays, and knock back a few for me. I'm heading out on 10+ days of snowkiting. But I'll be back here hoping you have cheered up.

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Re: Carbon vs Wood made boards

Postby iriejohn » Wed Dec 30, 2020 1:16 am

Matteo V wrote:
Wed Dec 30, 2020 12:55 am
iriejohn wrote:
Tue Dec 29, 2020 11:55 pm
True to form you were bullshitting and when called out you can't back off, so you predictably have no alternative but to continue in the same vein. :lol:
It is the only "vein" I have!
QED

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Re: Carbon vs Wood made boards

Postby Matteo V » Wed Dec 30, 2020 1:22 am

Matty V wrote:
Wed Dec 30, 2020 12:15 am
Yes I rather though the math was done long before you started in this topic, back when you were windsurfing?
No, it was done even before back when GraemeF/CaptainCore/Pinknorthpride's boat sunk, just before I was born!. So yes, he can claim he was sinking Kevlar boats before I was born.



Matty V wrote:
Wed Dec 30, 2020 12:15 am
Now your recently discovered Gurit page is your go too?
Yes, easy google search. Recent info on laminate comparison more or less confirming the materials science at hand. Great for those who have trouble diverting thier focus from people to the reality of the physics.



Matty V wrote:
Wed Dec 30, 2020 12:15 am
Now start looking at alternate resin systems.. and the effect that has on laminate performance
See, it did some good! Back in GraemeF/CaptainCore/Pinknorthpride's day, you just used polyester resin because that's what was available. Now we have better resins that can almost match the performance of the newer fabrics available.

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Re: Carbon vs Wood made boards

Postby TomW » Wed Dec 30, 2020 1:36 am

I've been researching this awhile, and building boards awhile.
Carbon is really stiff, but its brittle, resists impacts poorly, and once cracked will break apart.
S-Glass is stiff too, but has much better tensile strength and hence less brittle and better impact resistance.
E- glass is a significant step down from S - glass in stiffness, but has good tensile strength. Its used because its cheaper.

So adding glass, Kevlar or integra to a laminate in correct layup will improve impact strength and/or help hold the part together if the carbon fails.

This adds up to a situation where if you want flex in a carbon layup, you have to have enough to keep the elongation within the limits of the carbon , resulting in less flex.
S- glass is a better if you want flex and strength.
Carbon is better if you want no flex at all, and strength.

The core only needs to have compression and shear strength to allow the flex. PVC cores work well. Wood cores have some benefits in particular applications.

Paulownia is generally cultivated, is renewable resource, whereby PVC cores are based on plastics( petroleum-based product) and nasty industrial processes.
These users thanked the author TomW for the post (total 2):
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