I haven’t done the Kevlar/ glass thing myself. Kevlar degrades in sunlight. So you should paint it. Twaron is similar, but u.v. stable. Twaron is also black, not brown/ yellow. As far as flex and stiffness and the ride, unless you are using carbon which is 10 times stiffer than fiberglass, you won’t notice a difference in single 4 oz. Laminations.
Flex is better controlled with stringers, carbon, or thickening laminations with core type foams and wood, or microballoons. More on that soon…
…
A concept that many do not grasp…
Use wood…all problems solved !
Tensil strengh/ stiffness modulus/ elongation to break : E glass 2.5 GPa / 72 GPa / 4.5% ; Aramide (kevlar,twaron) 3 GPa / 130 GPa / 2.5% ; carbon HR 4 GPa / 240 GPa / 1.3% ; Nylon 1 GPa / 6 GPa / 17 %
E glass is 2.5 x stronger in tensil, 12 x stiffer. Nylon is a poor candidate as strenghener for composits, in fact is a far better candidate as matrix, that’s way we use panel of nylon reinforced glass to make industrial parts.
Hi lemat,
Nylon 6,6 is not the same as nylon.
Nylon is the name of a material patented by dupont de nemours in 1938, chemical name is polyamide. The most common by far is PA 6.6, in fact this is the one patented but they didn’t trademark the name nylon so it can be use for other kind of polyamide.
The mechanical properties i give in my post is for nylon 6.6. Evolution, for composits application, patented by dupont too in 1965, was polyamide aromatique contracted as aramide named “kevlar”.
Hey FH, I know you angled this question at Lemat and Every, so I hope you dont mind me chipping in. Kevlar has better stiffness than e-glass, so only cost would be a driver for such a cloth. We had some offerred by a weaver’s rep about 18 years back. No one bought any of that hybrid for that reason. The only time I’ve seen it used was for a light aircraft engine cowl, and I still think its a bad idea, just dig deep. Cheers,
Thanks Martymo
Happy for you to chime in! So if cost was a lot cheaper you would of tried it out…(say the cost of s-glass?) Or would of left alone? Just with all this debate on products that people haven’t used… It’s good to get real world experience…
Anyone else who wants chime in who have used products like this please do!!
So lemat just to double check you are saying if you did use nylon 66 or aramid it would be better in a hybrid cloth with fiberglass? … As my question above … would this be better than e glass on a surfboard… If it wasn’t so expensive?
Cheers
I want to thank you all for your responses.
So what I’m gathering is this: there may be a weak hydrogen bond between the nylon and epoxy, but this bond by itself probably doesn’t add significantly to the strength of the laminate. If anything, this feature may aid in saturation of the accompanying reinforcments in the laminate (which is helpful, as unsaturated fibers create a laminate that is effectively compromised).
Personally, I think there is something to the proper usage of lightweight Cerex in a laminate, but I view it as more of an ancilliary material, not a reinforcement per se. This is why I think you’re better off using the lighter weight versions. Skinz weight is spot on. There’s just too much good feedback (not just in the surf industry) and it just makes sense to me for various reasons, but I won’t get into that because that wasn’t the purpose of this thread.
Foamhack, I’ll continue to follow your nylon thread with much interest. You’ve got access to some cool materials down there. I have yet to find anything like them in the states.
Everysurfer, one day I may get some cordura. I’m not there yet, but one day. The universe of potential materials is so vast, and right now I’m just trying to get a decent shortboard made before the first real tropical swell lights up the Gulf of Mexico. For now I’m sticking with fairly conventional materials.
Lemat, thank you as always for your input.
Where on the Gulf of Mexico?
One of my clearest memories of my days on the Gulf Coast is of a very nice hurricane swell as it built at Quintana/Freeport.
But many of my best days happened when solid cold fronts had moved off shore and slowed or stalled over the Gulf – spring and autumn.
Thats a good point FH, the outfit I worked for bought so much kevlar, we could get pure kevlar at a decent price, but glass/kevlar hybrid would offer us mortals a performance and cost halfway house, just a pain to sand. Cheers!
Here some is… Bit heavy though… http://www.composites4u.co.uk/composite-fabrics/hybrid-fabrics/Glass-Fibre-Aramid-390g-2-2-Twill-1m-Wide
Here’s a thing you can try. Next time you hot coat, leave the tape on until the resin fully cures, then try to peel it off. After you are done swearing at me for telling you to do something so stupid as that, because it won’t peel up, ask yourself why it won’t come up. Its only the glue of the tape holding it down. Nothing different there.
But the tape now flexes less because the resin covering it made it thicker/ so stiffer. It spreads out the load of you trying to peel it up, it increases the area of glued tape you are pulling on.
What’s my point? If you take out the stringer, and get all your flex control from the skin, you get a board that flexes and rides the same, but is much stronger.
How does this relate to cerex and nylon bonding, and the subject of this thread?
More to come soon…
Based on Lemat’s comments regarding elongation
so if you glass a board with tightly stretched bamboo cloth with hemp reinforcements using RR2000 or ResinX epoxy in a bag with perforated peel ply to extract all the excess resin, do you end up with a stronger board?
If its elongation that’s the trick then wouldn’t natural fibers such as bamboo or silk be the balance between elongation and fiber glue saturation?
seems like you’d want a fuzzy fibered skin that penetrates into the core anchored and protected by the glue.
Reminds me of what Bufo is doing with Hydroflex
Makes sense to move away from tiny woven threads of glass to something else
if you think about Bert’s original thesis of saturated wood fibers under pressure as a skin it makes allot of sense with all the microscopic hollow veins within the wood fiber being saturated with epoxy. I have the diagram somewhere but I bet most who read it never caught on to what he discovered,
I have a bunch of Brian’s bamboo cloth from Greenlight i can play with (stretching it tight enough is the challenge)
If I merge that with Huie’s nylon mesh fiber underneath like foam hack has done with his recent build and some veneer to make a natural fiber sandwich skin
and one of our special xps/eps dual cores with a full bamboo mat springer and no wood skins
might be a good next esperiment for the Ewa Beach brother hack squad… thanks for the inpiration mr morey
From all free studdy i can read, composite laminate with natural fiber have disappointing inconstant mechanical properties for the moment.
Elongation is just a propertie. Fiberglass is constant, cheap, have homogeneous characteristics and is easy to use, a good basis for me that can be improve with more “exotic” materials and way to use.
Oneula,
The tighter you stretch a fiber, the closer it is to it’s breaking point.
Oneula.
Something like this?
This one is an EPS blank with Cerex Orion 0.7 oz with Hex Deck and Bamboo composite cloth…
Agree with Everysurfer… The Bamboo cloth that Greenlight used… (Do they still?) … has Lycra and Bamboo already stretches - what I found if you stretch it too much it cracks… a 100% woven bamboo cloth or this new composite (mix of bamboo, linen and something else … ) stretches way less and has a lot less cracking issues…
The mesh I use (Hex Deck) is different to Huie… I gather… becuase its hard plastic nylon hex shapes woven into a nylon fabric… I think Huie’s is different because he can wrap around rails? I dont think you could do that with the product I use… I will have to ask Sanded (the guy who imports it in)… to see if it the same as Huie’s…
Best natural fibre cloth I have found is Banana… though so expensive to get Down Under … and customs issues (government worried about the disease issues arriving in oz) … it gets stronger when wet?.. Weird hey?.. Thats one for the chemists on here… why?
cut a banana tree and see what’s inside its a fluid/water highway
that’s why we use it in our imu’s to steam cook our pigs and not roast them
its the same picture of hollow micro tubes bert showed of his microscopic view of his balsa panels
the problem we’ve always had with the bamboo is managing the resin saturation
when ever we’ve used it it soaked up too much resin but we never bagged it
if you ever seen a guava switch you know how tough it is
charlie uses obeche inserts to achieve a similar result
our bamboo mat internal springer does something similar to our prestressed/bent blanks similar to what’s called incide tech these days
with that the shell no longer needs to be a monoque stringer anymore just needs to be strong enough to protect the outside of the foam
so much work though for what though?
sometimes a heavy volan glassed tanker or a rubbermat is all you need to have the most fun in the lineup
