I hear hints here and there about the improvement of certain strength characteristics with the combination of innegra and carbon fiber. I’ve searched the likely places for more info and com up short. Does anyon have any info on this to share?
all the best
Dwight from foilsurfmachine do this with by vacuum bag carbon over plain wave 4oz inegra with amazing results. There is a canadian canoe builder that use co fiber glass inegra for building realy strong boat. There are many application where inegra is use to avoid fragile fracture in many dangerous parts of carbon. Need a good process and appropriate resin.
This may be slightly off topic, but there is a builder up in Oregon (Jason Tilley of Tilley Surfboards) who is using a Carbon/Innegra hybrid cloth to wrap the rails on some of his epoxy kiteboards. They are EPS blanks with Wood skins top & bottom & the exposed C/I rails. Two of my local friends own them & they are truely beautiful. They arre too nice to use; you almost want to just hang them on the wall & admire. Jason’s woodworking & bnoardbuilding skills ae incredible. I would kill to have even half his skills.
Lemat, can you please explain the engineering behind the combo?
all the best
There is a innegra channel on YouTube, if you haven’t seen it already. I think the plastic fibers like diolen and polypropylene can take a part of the impact energy and convert it into heat without being destroyed, if I got the concept right…
You can buy Carbon/innegra hybrid cloth , its about 6 oz , I have not used it , kind of expensive , about $40 a yard I think .
Graphite Master has sooo much variety of fabrics and cuts yardage. Almost anything that has ever been discussed on Sways can be sourced thru them. Anything you’ve ever seen on a Lost/Mayhem board can be bought from Graphite Master. No website though and a little slow to get back to you on inquiries, pricing etc. but they have it all. Lowel
Ours is $20AUD a metre!
Carbon Innegra diamond weave
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Well it’s a bit counter intuitive for me… But the facts seems to show it works.
It’s the plastic in elastic theory : inegra is Polypropylene (PP), like other plastic of same family (PET polyethylene therphtalate, PA polyamide, …) it’s a moderate stiffness material with high elongation to break and high plastic behavior. Plastic behavior is something that dissipate energy while deforms without fail and don’t come back to is original shape (elastic behavior like carbon epoxy, glass epoxy,…) When mixed in composit layer, carbon take load and give the elastic behavior while inegra dissipate some of deforms energy up to carbon break. so stiffness come from carbon, and skin thickness for flexural stress, inegra help to dissipate energy, increasing impact strength, élongation to break and dampen elastic behavior.
Resin must be able to work with both in same time and problem is that inegra don’t glue well with resin, like all plastic (low polarity materials).
Thanks Lemat. That is what I was looking for. It is counterintuitive. But it is the very definition of a two-phase material, a strong component with a high break strength and relatively high modulus of E. And a matrix component with lower modulus with about 1/4 of that of the stiffer material. But I’m just not seeing how the poorly bonding innegra works with carbon. But by some accounts it does seem to do just that.
I would have guessed (wrong) that the carbon would fail on impact leaving the innegra to carry the impact load and then it would fail in sequence. Apparently, I don’t understand.
all the best
you understand well, it’s what happen when break and because inegra is a ductile material it’s stay in one soft part, it’s a security component for racing car parts for example. What is interesting is also what happen before break, the mix components allow carbon parts to deform more before come back and reduce speed spring back which dampen the flex. You can obtain similar behavior by using “plastic” resin or plastified brittle resin.
I was wondering the other day if anyone was still using Innegra. What you said above comports with my experience using it to build a board-
At first I was really disappointed because the board was completely dented up after the first couple of surfs (…“deforms…doesn’t come back…”). However over the years it has held up. “…without fail…”
When making the board I could not tell when the cloth was saturated- it doesn’t turn clear like normal glass cloth. getting the right amount of resin is tricky.
As far as it not “glueing well” I remember being told to combine it with nylon non woven veil (“skinz”) which helps prevent delam. Although the board is really badly dented it has never delammed. I’ve continued to use the veil under veneer skins for that purpose (adhesion, preventing delam). Plus it adds very little weight.
I stopped using Innegra because, if I understood correctly, it requires you to vacuum bag the laminate (the 2oz coth would balloon to the thickness of 6 oz cloth before bagging) and that process involves an excess of consumables for my taste- release cloth, breather cloth…
I positively love using veil for adhesion. I’ve been using veil with veneers and when gluing up the G10+ply fin panels and it works great.
nylon veil is stretchable and allow a “thick” (resin rich) layer of glue that’s the key of gluing with resin even more if you clamp with a vacbag. But because it’s plastic nylon (polyamide) have a low adhesionby itself with resin, the really open structure of lightweight veil compensate this problem. An other way to increase bond is to use a real glue. Structural ones are mostly tixotrope small fiber resin mix gel more or less flexibilise depend of material and final stiffness. Most of time the key is glue join need to be more stretchable than stiffer material.
because surfboards skin work in flexural way, skin thickness contribute a lot for skin stiffness so it’s not a bad thing that inegra balloon, because it’s light and allow a thicker skin with less weight than glass… like bulker often used in composits.