A cloth and resin laminate done with a squeegee will be just as strong as a vacuum bagged laminate if the same cloth is used in both cases but it will be heavier and thicker. It is only if the finished thickness and weight of the laminate is specified, that the vacuum bagged laminate will be stronger due to a higher cloth to resin ratio. Squeegeeing carbon fibre cloth is a legitimate technique.
Not entirely true - over saturation is as bad as under saturation- making it brittle. The resign pooled will break, and you’re left with unsaturated kevlar fibres that rot and delaminate.
I probably mispoke and should have said that it has great Izod Impact resistance. Meaning that it gives but resists breaking. Could be part of the reason they use it in bullet proof vests. Where as carbon fiber is weak in this application.
What about using stronger foam to begin with? We use some xps insulation foam for beneath high-load concrete pours that has a compressive strength of 100 psi. Don’t know what a normal poly or eps blank will wistand but I don’t think it’s more than 20 psi.
That can work, but again - weight is always the issue. Anyway, I’m giving carbon a try on about a dozen boards and will let you all know how it pans out for your own future refference.
Corran
(ps - kevlar in vests is UNLAMINATED - laminating actually weakens kevlar. Sun makes it rot… water makes it rot… its actually not fery freindly stuff
Thre is a brief piece on air-core design, carbon-fiber surfboards from Halun Surf in the new TSJ. Check out www.halunsurf.com. From their website:
“Halun Surf is the designer and builder of the next generation in surfboards. Our KOLSTOF surfboards are constructed out of carbon fiber as well as other technical fabrics and materials utilizing aerospace technologies. This airframe construction with an air core makes them light, strong, and very buoyant.”
(ps - kevlar in vests is UNLAMINATED - laminating actually weakens kevlar. Sun makes it rot… water makes it rot… its actually not fery freindly stuff
Kevlar is also made in different formulations, the structural stuff and the ballistic stuff are not the same thing. I’ve been told that the dyed kevlar often used in carbon/kevlar hybrid cloths is always ballistic grade, and not as strong.
Dyed kevlar Is not always Ballistic grade… Type 49 and type 149 kevlar ( structural type) is available in a myriad of colors, often confusing composite techs as to the actual type of material it is. As for impact resistance it is a known fact in the composites world that kevlar is much better at impact resistance than Carbon fiber…while stiffer than fiberglass, carbon has a much lower impact resistance than fiberglass. Kevlar may also be the answer for your weight concern as kevlar is 43% lighter and twice as strong as E-type fiberglass.
Isn’t kevlar a material that GIVES, instead of resisting like carbon?
As such, it gives so much the underlying layer of material gets broken, with no resistance from the kevlar. Bad…
Just curious, but how does carbon resist an impact when it has a lower impact resistance than fiberglass.
I agree plastic CURRENTLY is the best for a hi impact resistance surfboard but there are other alternatives… carbon isn’t the correct one IMHO. It’s a step in the wrong direction.
If the underlying material of kevlar is damaged / compressed isn’t that more effective than a shattered layer of cloth with a damaged core material? Most carbon used for structural applications has a fairly hig modulus making it very stiff, ergo more shatter prone.
Lots of wrong info here. First carbon is stiff and has the best compression strength of any FRP composite material. Compression strength is the most important strength characteristic in surfboards. One of the real advantages of this high compression strength is thatboards built with carbon can be made much lighter and different foams and resins can be employed. It’s tensile strength is also quite good which makes the usual composite inequality problems, compression strength vs. tension strength, better with carbon than with any other FRP material (fewer broken boards). Depending on the resin matrix (resin modulus), carbon can be a fair to excellent material for surfboards and this matrix has as much to do with carbon being seen as brittle as any other reson. Carbon is commonly used in resins that are lacking in the properties it demands. Hence the “brittle” reputation. Using correct resin modulus is one key to using this material successfully.
Carbon also has the best resistance to fatique of any FRP material, which means boards built with carbon, in the correct epoxy matrix and with the right combinations of other materials, don’t break down as fast. It has excellent return aspects which makes it very lively in the water and gives positve return. People here who think it’s too stiff just haven’t found the right COMBINATION of materials. That’s what this is all about, engineering the next step in surfboards using ALL materials that are available to us. Changing one aspect or material in a board probably won’t net you a positive result. Open your minds a bit more and you’ll see WAY more possibilities.
Building a board that simply flexes with no return and you have a Morey-Doyle. Noodle surfing… yuck! Building a board that is stiff with no flex and you have a Surftech. Stiff, unforgiving and no feel… again, yuck! Building a board that gives the correct flex with return and can do this over and over without fatique and breakdown, that’s the key. That’s what doesn’t exsist in the upper levels of the sport right now. The only way the pro’s have been getting this positive flex/response/return is through disposible surfboards. The materials and engineering are available to do this much better, with even better flex/response at lighter weights AND with durability. Understanding how surfboards need to react is the first step in this engineering process. I can assure everyone here that carbon will be part of future boards. Again, it comes down to COMBINATIONS of materials.
I agree with you that Carbon is a much better material and Has Its merits which far surpass fiberglass but what do you think for it to be used as a primary material in a surfcraft that is prone to contact with rocks? IE A River surfboard. I have used carbon in my boards and have been very happy with the materials merits but I wouldn’t want to surf a carbon board in a splinter creating environment and I would gladly take a fiberglass splinter in the skin than a carbon splinter any day!!!
Greg answered in the context of a regular surfboard, used in ocean surf, by surfers who don’t always grind their boards on the rocky bottom.
Sorry Greg, you know your stuff, but in this case, your answer is NOT applicable!
Main question on this subject is suitability of carbon fiber or exotic materials when used as a riverboard, needing resistance against contact with the rocky bottom while being ridden by a surfer!
A river bottom bed is more abusive than 7 little kids with hammers, as the speed the board is DRAGGED across the bottom is the most abusive damage!
THAT’S what my replies have referred to, not whether carbon is good or bad in general for normal surfboard usage.
Well, I’ve made a half dozen boards out of carbon now and we’ll see how they hold up. So far so good.
one cool thing - I made my last board the same shape as the previous one, but in carbon, and the differance in feel is astonishing. MUCH crisper feel on the water. The entire board is stiffer from end to end and its a strange feeling, but very cool.
Corran
Kevlar - another real problem is that UV light deterioates the fabtic drastically so the “life” of the board would be reduced.
Sorry, I was posting in reply to the many on this thread and others that there is something wrong with carbon on surfboards. Simply, there is not.
In regards to river boards and rocks, simply use polyester fabric called Xynole in conjunction with RR 2020 or 2040 epoxy. Xynole is available through Defender marine in NY. They even sell cut yardage. I’ve built hundreds of boards this way and it’s ideal for this use and Xynole doesn’t have the issues that Kevlar has (UV, cutting and sanding, etc.).
Hemp cloth is also reasonable to look at for this. Available through Hemp Traders in LA. www.hemptraders.com or 310-914-9557. They also sell cut yardage. I’d suggect the 7.5 oz. 100% hemp summercloth again with 2020 or 2040. Also using 1# eps with a heavier lam schedule will work better.
…carbon is stiff and has the best compression strength of any FRP composite material. Compression strength is the most important strength characteristic in surfboards. One of the real advantages of this high compression strength is that boards built with carbon can be made much lighter and different foams and resins can be employed. It’s tensile strength is also quite good which makes the usual composite inequality problems, compression strength vs. tension strength, better with carbon than with any other FRP material (fewer broken boards). Depending on the resin matrix (resin modulus), carbon can be a fair to excellent material for surfboards and this matrix has as much to do with carbon being seen as brittle as any other reson. Carbon is commonly used in resins that are lacking in the properties it demands. Hence the “brittle” reputation. Using correct resin modulus is one key to using this material successfully.
Carbon also has the best resistance to fatique of any FRP material, which means boards built with carbon, in the correct epoxy matrix and with the right combinations of other materials, don’t break down as fast. It has excellent return aspects which makes it very lively in the water and gives positve return. People here who think it’s too stiff just haven’t found the right COMBINATION of materials. That’s what this is all about, engineering the next step in surfboards using ALL materials that are available to us. Changing one aspect or material in a board probably won’t net you a positive result. Open your minds a bit more and you’ll see WAY more possibilities. Greg, please continue. Which of your epoxies would you recommend for use in a carbon application? What is the “right combination of materials” you are speaking of here? What kind of glassing schedule would you use on a stringerless eps short board.
Hey…I just did a search on Carbon as I was interested in these boards and stumbelt over this thread.
I was wondering if a hollow carbon board with some kind of surface finishing would be a good idea. This would add quite some weight though.
There used to be skateboards covered with a clear poly coating, they where known as Slickboards. The whole idea was to protect the graphics and the deck itself…
I guess you have access to some HDTP Corran ever tried to coat the carbon surface?
Another alternative is something like this - http://www.surflight.com/ - custom shaped, engineered flex, soft skin. I don’t know how they hold up to abrasions.
I’ve made hundreds of boards from carbon fiber, carbon/Kevlar, and Kevlar. Making a board that would handle impact wouldn’t be that hard. Making one that would resist abrasion is another story. If you’re just bumping into rocks try 8 oz carbon fiber with a separate 2 oz Kevlar layer over it. If you’re grinding rocks, I’d do some sort of soft-top deal. Make a rigid core, and wrap the outside with a layer of boggie board foam.
