Carbon Fiber Longboard questions

Okay I’m going to visit a shop to watch a local shaper put together a board. I’m planning on building a 10’ noserider in the future. I plan to build a few smaller 4" boards maybe a 6’ board to get the hang of glassing and shaping. The 4’ ers I don’t plan on riding, maybe give them to a few local youngsters, but I figured it would just give me an opportunity to figure out how to glass the top and bottom and work the resin and mat.

My question is two fold.

1.) I plan on using an EPS core with epoxy over Carbon Fiber I’m a fairly thick guy (about 5’8" 220ish) and I’m tired of renting longboards for the crap surf we have down here in Galveston Tx. The only thing they rent down here is BIC boards which the last 10’ I rented was exponentially harder to paddle then my 6’8". As I kid I had a 30lb old school log and it was 10x easier to paddle. I don’t know if it was designed for gromm’s riding foam on the inside or what, but I simply couldn’t paddle out with the other longboarders on the outside and catch the waves. I got some nasty looks sitting on the inside with the rest of the shortboarders until I caught a few waves and they realized I wouldn’t be floating sideways in the middle of lineup with my arms draped over the board. I’m a school teacher so having my summer off allows me to experiment a bit. I was wondering if I could put a single layer of 4.8oz CF over bottom, and use a single 5.8oz top on my board. It’s a single stringer blank. I just was wondering if i HAD to use a stomp patch. I’m trying to save a few bucks (since us teacher have such wonderful pay in Tx) and not have to use a stomp patch by going with a 5.8 on top. I can use 4.8oz on top with a stomp patch, but it will run me about $40 more in materials if I do.

2.) looking through the suppliers I found there are a couple types of weave that I don’t know much about.

-Style 284, 5.8 oz./yd.² (197 g/m²) 12 Warp 3K Carbon X 12 Fill 3K Carbon, 2 X 2 Twill Weave, 8.7 mils (.22 mm) Thickness.

What is the “Warp” type on the fabric. I understand a bit, but don’t understand if I need to use that in my board or another type of fabric.

Thanks for all you guys help so far, this site is a excellent resource for guys looking to do a bit more the go to the store and buy um off the shelf.



While carbon can be used in conjunction with glass to form a stiff, non breaking longboard, by itself, it tends to dent easily, deform on buckling loads, delam, and sheer fail, leading to a broken or crumpled board even in small, waist high Texas musher waves.

Now if you were to use your carbon WITH one layer of 6oz cloth, you’d have a pretty break proof board that would dent easily, and delam sorta.

Probably strongest with one layer of 8-9oz Volan on the bottom, and a full double on the deck WITH patches for your knees, for kneepaddling if you do that, and also for your back foot area.

Make it thick, sorta wide at 24", and you can go shorter down to around 8’.

Could you explain a bit please? From what I’ve found in other relms, automotive, aviation and such. Carbon seem to be very strong and have good tensile strength. I don’t understand how it would dent easily, deform or sheer fail under conditions as you stated. I’ve personally seen guys jump on fenders made of 4.8 cloth and they just bouch right back, as well as hoods and wings made from CF with no fiberglass. How would fiberglass strengthen the board when fiberglass itself is weaker in all essences from what I’ve found from similar CF sheets. I mean wouldnt’ a 4oz fiberglass with Poly resin be much weaker then a 4oz CF with epoxy? I figured 4oz CF/Epoxy would compare to a 6oz Fiberlgass for the bottom. The top is where I really didn’t know if I could get away with one top sheet rather then go with a single Fiberlgass sheet with a stop pad.

I’m not a knee paddler so that’s not a concern. I’ve heard of the delam being an issue unless you vaccume bag the board, but I’ve heard mixed reviews whether it’s actually factual or just bad layup on the board that causes it in general. I’m VERY interested in learning as much as I can in the differences between the two cloths and where and when each shoudl be used. Any more information would be appreciated.

It’s quotes like these that get me confused…seem to be very conflicting opinions…

"Using carbon is not unlike using fiberglass. I never found it difficult to cut or work with and with Epoxy you can get it light and super strong. Carbon comes out in a laminate double the strength of regular fiberglass cloth. In other words one layer of 6 oz. carbon is equal to two layers of 6 oz. glass. Use it this way and you’ll be successful. It is black so if you have a problem with that you’ll have to paint over it.


Carbon by itself is indeed double or more stronger than fiberglass cloth.

But when used with styro or polyurethane foam, you need an intermediary bonding layer, as compatibility issues arise when you mix super stiff (carbon), with very weak (blank).

Shear loads induced on a longboard, even in small surf, is quite a bit higher than just leaning on, bending, or standing on a piece of carbon fiber. Think of the surface areas you have introduced, think of the power of a shoulder high wave knocking YOU, at 225lbs., back on your heels. Now you are round in shape, somewhat hydrodynamic. The top and bottom surfaces of a longboard is relatively flat. AND…very thin, like 3.5-4" max. Mix the two together, add a wave, and you get…SNAP, sheer load crumple compression.

That’s why, almost all longboards, not all, but almost all, are made with double layer deck fiberglass, single or double 8oz bottoms, NO carbon, and they are durable and economical.

So as you were saying before about laying up with fiberlgass first then going over with Carbon Fiber. If I were to lay up the bottom with 4oz fiberglass then 4.8oz Carbon would that be comparable, or better then an 8oz fiberglass layup. On the other side, litterally, Would doing the same with a 6oz fiberglass with a 5.8 carbon Fiber layup provide any benefits. I just would hate to shape a board go through the joys of learning how to glass it, Only to have it snap on the first time out in decent surf.

What about the I beam effect that some claim to get from the stringer in the EPS blank and the carbon layup.

So kinda just to sum up what your saying…let me know if this is true.

The flex in the blank combined with the rigidity of the CF skin don’t mix well causing, instead of flex, a breaking point due to the imcompatability of the two materials?

While carbon fiber is very strong in tension, it’s not the greatest laminate in compression. A bad analogy: a wire cable or a chain is great for towing something, but you can’t push it especially well.

The real weakness is where the foam/lamination bond fails: you get a soft foam that’ll flex a great deal glued to something which in the case of carbon fiber doesn’t stretch at all. So the foam breaks away from the laminate and the board fails. Bear in mind that the bond that holds the laminate and the foam together is only the resin penetrating into the voids and such in the foam, maybe 1/16- 1/8".

The claimed I-beam effect of stringer and lamination isn’t nearly as good an I beam as has been claimed. It makes some contribution to initial stiffness but its contribution to the ultimate ( breaking) strength of the board is minimal.

Now, if you’re talking about a board with two ~4 oz plus epoxy laminates on the bottom and two 6 oz epoxy laminates on the deck, why not go with fiberglass cloth rather than carbon fiber? It’s much easier to work with ( you mention you’re learning to glass on this one, no? Learning shaping too? ) , a helluva sight cheaper and won’t be appreciably weaker for your purposes. Add a deck patch if you really want to go rugged. Easier to do, cheaper and it’ll work as well for your purposes. Try carbon fiber on the next one.

hope that’s of use


Thanks doc. I was actually thinking about doing this on one of my boards down the road. My roommate is a Carbon Fiber fan so I wanted to accomidate him. The Fiberglass is definatly way cheaper though. I may still use expoxy resin just for the hazard factor of using Poly resin. I’ve done a bit of glassing with poly and the smell you have to get used to.

BTW doc let me know what time tomarrow to meet you.