Hi, I’m planning on making a fish (oldstyle keelfin) from Eps epoxy carbon fiber. The carbon weave I’ve been offered is 220gram (6oz?) twill weave? Do you think one layer of this on each side will do? Also, I think I’ve read somewhere that if You glass a board with carbon weave You’re supposed to put a layer of thin 2 oz fiberglass on top to protect the carbon from sanding? All answers appreciated Thanks Erik
Erik: In terms of strenght my experience is that you should only need the one layer of six oz.carbon. As to ease of sanding, a layer of four would provide a warning when the sanding is getting close. However, I have found that adding the extra layer of four adds a lot of weight. What I have done on my latest project is to use three layers of epoxy; one to stick the cloth down tight, one to fill the weave, and one to bury the cloth. Using this method the sanding of the cardon was no problem. As to the weave, I would do a small test run to check out how it will sand. Hope this helps some. Good luck. Patrick
wouldn’t the carbon fiber, make the board stiff, with very lit flex
Yes would probably make it very stiff. I’m no expert boardbuilder but I was reckoning on not needing so much flex in a thick Old school fish but instead make it very light for speed.
dj; Greg has addressed this issue somewhere in the “Archives” I believe his company “Resin Research” covered the problem by developing epoxies with different flex characteristics. How they would work with carbon I don’t know. Perhaps Greg will see this thread. Patrick
Erik; I am no expert either but I agree with you on not needing a lot of flex on a classic fish. Usually I think of a classic fish as a being surfed fast down the line with a big turn at the end with a lot of spray(at least that is how I try to surf them). Accordingly, the design principle of stiffness=speed should apply. On the other hand, Dales mats are said to be very fast and they are very flexible. Probably another case of what is the compromise. Patrick
Erik, making a carbon fish sounds like you like to try stuff. Instead of extra glass, try mixing a little cabosil/aerosil in the hot coat. This will thicken it a little and allow you to sand with less chance of sanding through.
Thanks everyone, I’ll post some pics if I go ahead and make one Erik p.s wintersurf tomorrow in the Baltic Sea 
One layer of 6 oz. carbon should be adequate. Use a stiff epoxy to match the stiffness of the fabric. Also a twill weave should hot coat smooth like a 4 oz. plain weave glass. When laminating, pour your resin, spread it around and allow it to soak through the fabric. Twill’s are hard to saturate but epoxies usually do this fine, you just have to allow the soak time. Then use a very stiff sqeegee and push down hard. You have to stick a twill to the blank very tight, much tighter than a plain weave. Twill’s also tend to want to get bubbles underneath the cloth. This is made even more difficult because you can’t see through the carbon. Pushing the sqeegee hard will solve this. And don’t worry about air, the twill is very hard to make too dry.
Hey Gregg, How about using a wide roller? It seems to me it might make for a great job. Mahalo, Rich
hello, i made a carbon fibre old school fish last year using a normal blank rather than a eps one .just one layer on each side, the carbon is not much differant to glass cloth to use, you just need to be a bit more carefull with your sanding .this was the second carbon board i have made .with hindesight if i make any more i would probably try two sanding coats together to give a bit of extra depth to sand flat. the blending of the deck layer of carbon with the bottom can only be done cleanly and neatly by over lapping the deck layer onto the bottom and then sanding the deck layer back to the tucked under edge. i found it easier to apply tape to the bottom of the board about 1/4 inch in from the tucked under edge and then laminate the deck over the tape . the carbon can then be cut to the tape edge when at the toffee stage and then sanded back later. i would post a pic but i am not sure how to do it ,my email is if you want a pic ,pete
just one more thing your 220 gram cloth converts to nearly 9 onces so one layer would be bullet proof, pete
I don’t think 220g pr. square meter is much more than 6oz. 6oz pr. square yard is about 200g pr. square meter, 4 oz is about 135 grams. regards, Håvard
Hi again and thanks for all your help. Well here’s another question for You. I haven’t bought the carbon yet and I’ve got the option to choose between Twill weave or plain weave. The Guy I’m byuing it from is a big wholesale dealer in South Sweden, he gave me a sample (free) of the twill weave and told me that it’s supposed to wrap easier around corners than the plain weave. The question is which type of weave should I get? They’re the same weight (220gram) and the same price. What are the advantages and disadvantages of the different types of weave? Would one of them be easier to handle when glassing? Small but fun surf today, shoulderhigh water temp now only around 38f. Kind of refreshing… Erik
Having used both plain and twill for prototype and moulded applications, I have to say the twill is much easier to conform to complex shapes, particularly when you are using fabric around 200gm. As Greg said, use a fairly stiff sweegee/aplicator and be thorough in saturation and removal of excess resin. You should be able to get it really flat and tight making the filling and sanding easier. Good luck.
Hi Erik, I’m in the market for som carbon fiber as well. What are you paying for the carbon fiber cloth? regards, Håvard
I’ll ring the guy tomorrow, he’s qouted me a price before but I can’t remember! I only remember the price being quite low. here’s the webpage url: http://www.bhp-glasfiberprodukter.se/ Hade Erik
Hey Håvard, good news for You. The price for 1 square meter of 200gram twill carbonfiber cloth is 215 sek + 25% vat (moms in swedish). I don’t really know much about prices for carbonfiber in other places, but to me it sounds quite cheap. You can ring the guy on +46 40440710 he is very busy with his business but always very friendly and helpful. Good luck och gode bölger Erik
Thanks Erik, that is a good price, atleast from my standpoint. regards, Håvard