I’m a big fan of carbon fiber period, in my RC stuff, cars, surfboards, whatever, it’s an amazing material. Tell me, how hard was it to get it to curve like that? The last carbon fiber I used was unidirectional and was very stiff bending wise in that direction. Maybe it was just too thick?
Nice job. Hope it works good, that would be a good economical use of $Carbon. Good idea gluing in a centerline, I just did a stringerless, lack of centerline was a constant hassle.
What was the intent of putting carbon on the rail in terms of materials science? Was it to strengthen rails, reduce or control flex, or just cuz you could?
There might be better ways to accomplish the intent… rail glassing isn’t the most efficient use of materials.
I’m not speaking for Mr. Stamps, but with the outrageous price of carbon these days you can buy carbon tape at reasonable prices. I doudt that it was pre-set in resin before it was applied.
The tricky part is cutting the tape or cloth to follow the rail taper and foil.
Tim did you bag the carbon on or did you do it as a hand layup?
The thicker the board/rail the stiffer if will be. By varying the width of the carbon layup the flex may be altered to some degree.
It wasn’t very hard to wrap the rails. Basically did a double cut lap line and hand layed up the rail section and trimmed.
Yeah, the glue lines help a lot on stringerless shapes. Especially if you like to look at what you’re shaping.
Carbon rails as material science?..I did it of course becasue it could, but more importantly I was going for a perimeter type “stringer” system that was free floating on the rails. It’s my take on the Greenough/Firewire(BertB)and snowboard layup theory’s of using flex patterns to get you somewhere else.
Carbon, in my opinion, is a much more controllable/consistent medium than say, balsa wood rails or the available blanks with traditional stringer material(wood) running arbitrarily along the rails from shape to shape and blank to blank.
Some fine tuning needs to be done, but so far things are really positive.
Tim, nice work. I did the same a few years back for a LB for my son. I’ll dig up some construction pics and post. Two problems I encountered: I pre-wet the carbon tape and the carbon dust smeared onto the white foam as I applied the tape to the rails. I was able to clean up most of it before the epoxy hardened, but still a bit of a pain. I should have done cut laps, but instead just glassed over the whole thing. (I wasn’t sure how well carbon would cut). Turned out nice anyway.
Second problem was that when the inevitable ding occurred, the carbon fractured and couldn’t be repaired well. Mostly a cosmetic issue, but still an issue.
My hat’s off to you. Great idea. Doesn’t look too hard to do either. You can really play with the lap width to play with flex. I see some years of R+D to get that really tuned in to the point where you can control the amount of flex, but like you said it does seem more controlled than balsa (differing densities). Looks very cool too.
That looks really interesting, great work. Wouldn’t there be some sort of issue at the lap line? What with carbon being so stiff and the foam pretty flexible, surely there is a chance of failure along the joint line after fatigue sets in?.. It just seems that you have 2 very different materials being asked to behave in a complimentary manner. sometimes it works and sometimes it don’t, please let us know after 1000000 cycles what the fatigue limit is?!
This might be a dumb question, but how did you get that last picture “rail cross section”. Was that a test piece? did you add a tail block or something? I like the idea of keeping the rails light so that pivoting along the stringer, glue line, is quick and effortless. Nice Job.
My longboard pretty much does not flex. At all. Zero. It’s 4 oz Carbon Tape with double double 6 on top and single 6 on the bottom. 9-4, 22 wide and 2 7/8 thick. Based on what I now know about composite construction, there is little reason to wrap both top and bottom around the rails because the carbon takes up pretty much all the load until it snaps. Dramatically. Extra rail wrap is probably a waste of cloth, resin and weight.
take the two rails…put together…ellipse…pretty strong structure…add the crown in the deck for further strength…or what about a double concaved deck, 3 convex surfaces and 2 concave surfaces opposing one another…tension and spring…
pole vaults…hockey sticks…SUP paddles…bicycle frames…all hollow and pretty strong with carbon fiber. Balsa?
not knocking Bert, just another way to skin a cat.
I like it, of course, time will tell how well it holds up. Seems like a light, strong alternative to wood or PVC. Give us a ride test, both now and after a few months.
I would think, it would work better to make a full structure on the rail in carbon…Say, basically cut the rails off (at the edges of the carbon) and cover the foam edge in carbon then re-attach it. That way it would be a solid structure. Instead of just laying over the foam?
If its good or bad, let me know. Just throwing up my take on this!
