What different materials and construction techniques have people here used for fins ?
And, what did you like about the results ?
Some examples to get us started…
foam [pu and eps], carbon fibre, epoxy , wood, metal, graphite, polycarbonate.
Combinations of any of these…and any other materials used ?
I’d be keen to hear from the experimenters out there …
thanks !
ben
Flesh and muscles. Seems to work best for me.
He he he he he he he he he he he he he he he!
Flipper.
Flesh and muscles. Seems to work best for me.
He he he he he he he he he he he he he he he!
Flipper.
Yep , works for the big guy too …
…We now resume normal transmission, thank you for your attention…
Chipper
Chips, that must be a pic of you at your new shaping machine!!!
I’ve made fins from plywood, fibreglass layup, moulded, foam filled moulded, hollow moulded, and hotwired vac bagged.
If you use ply, make sure it’s marine ply, or you will have to glass it and reinforce the base if it’s going in a box.
I never really enjoyed foiling fins, but the multi-colour lay-ups make a good looking fin.
What sort of wild idea are planning this time?
Also: Polypropylene cloth (interior intermediate laminations).
In regard to the use of carbon fiber (unless molded), I’ve always been under the impression that it should only be sanded under exceedingly stringent exposure control methods since (allegedly) carbon fibers (apparently unlike glass fibers) can, over time, work their way all the way through the body (including through internal organs). Anybody have some definitive references–one way or the other–on this?
mtb
Also: Polypropylene cloth (interior intermediate laminations).In regard to the use of carbon fiber (unless molded), I’ve always been under the impression that it should only be sanded under exceedingly stringent exposure control methods since (allegedly) carbon fibers (apparently unlike glass fibers) can, over time, work their way all the way through the body (including through internal organs). Anybody have some definitive references–one way or the other–on this?
mtb
I read the MDSS for grinding glass cloth and for grinding carbon cloth. Both are dust hazards, neither is carcinogenic or leads to anything worse than a sort of dust accumulation syndrome. For either good ventilation and a dust mask are a pretty good idea.
I’ve done basic glass/resin and glass/carbon/epoxy layups. I’ve always wanted thinner stiffer and stronger and have been reluctant to try low density fillers.
Oh yeah, I made a few Lexan fins too, not stiff enough for me in the common fin thicknesses. Sure looked cool though. Like a big icicle.
For whatever it’s worth, I’ve worked with carbon for over 20 years and I haven’t had problems. (except for that large growth that they cut off, called it Ben, and dumped it in a septic somewhere in west Australia!)
-Seppo, over and out!
Nothing I saw regarding carbon fiber (and sanding thereof) looked particularly dire, but it’s certainly worthy of protective gear for your skin & lungs…here’s an excerpt from OSHA (emphasis added):
Pitch-based carbon fibers may be associated with an increased risk of skin cancer, although the evidence is weak. PAN-based carbon fibers did not cause tumors when the same test was conducted. Standard mutagenicity tests conducted on PAN-based carbon fibers were negative.
The principal hazards of carbon-fiber handling are mechanical irritation and abrasion similar to that of glass fibers. Skin rashes are common and reportedly more severe than from glass fibers. Carbon fibers commonly in use are also greater than six micrometers in diameter, making them unlikely to be respirable. An ongoing survey of workers in a carbon-fiber production plant shows no pulmonary function abnormalities and no evidence of dust-related disease.
Carbon fibers may be coated with a material to improve handling, known generically as sizing. The sizing materials are typically epoxy resins. They may be biologically active and cause irritation or sensitization.
Blakestah, Aquafiend65, Keith…
Thanks for the info.
mtb
Chip, that must be a pic of you at your new shaping machine!!!
What sort of wild idea are you planning this time?
A picture speaks VOLUMES ?? …
I’ll leave the ‘wild’ stuff to you mate…greg WILD !!
…but I do have a few ideas kicking around…
ben
For whatever it’s worth, I’ve worked with carbon for over 20 years and I haven’t had problems. (except for that large growth that they cut off, called it Ben, and dumped it in a septic somewhere in west Australia!)
-Seppo, over and out!
how rude.
So tell me, gaylord fokker, [not rude at all…his real name is GARY …at least he didn’t call HIS daughter ‘Martha’ !]
…how was making fins out of carbon fibre cloth ?? Was / is it easier or more difficult to foil than silane 4 or 6oz, or about the same ?
Also, anyone use[d] kevlar at all ? …or is it true [what I heard] that it’s a bit ‘crumbly’ when sanding/ sanded ?
thanks !
ben
Kevlar would make great bulletproof fins that mangled with each hit.
Bonding issues, as it just doesn’t like to saturate with resin of any sorts.
Carbon is applied over a mold, so any sanding is only cleanup, not for the foil! Mold is usually foam stryro, poly, d-cell, or airex. IT is foiled precisely.
Lots are made with separate halfs, then bonded together and wrapped by hand at the leading edge, resined at the trailing edge.
Hey ya Ben,
carbon sands/grinds/foils great. It cuts supper clean and a little cooler I think.
Forget about kevlar. atleast in this way. The fibers don’t “shear” off leaving a clean surface. If you sand it it fuzzes up really badly. Imagine a real heavy peach fuzz. You then have to re-wet it with resin, which adds weight, until you 've built up a thickness greater than the fuzz. However, if you’re molding it and essentailly don’t have to grind/sand it kevlar offers some very interesting characteristics.
thanks LeeDD !
Is it ever laminated in conjunction with something else like, say, carbon fibre ? Or would that still not work ? I know a glasser guy here who puts kevlar strips down the stringer of some of his chip thruster boards.
… What kind of stuff / materials are happening with windsurfing and kiteboarding fins, I wonder [in smallish surfboard sized/ usable fins ?]…because it seems to me [as a semi ignorant observer] that THOSE wave riding craft sure take some solid hits from time to time !
ben
Lotsa our top board builders, from Gary Young (lived here until the mid 80’s), MikeZaicheck (top epoxy/styro windsurfboard builder), JonahLepak (SantaCruz, but from Sausalito) tried Kevlar in varous forms and layups, but all have given up on it.
It’s properties are almost the opposite of carbon, so any mix is a bad combination of extremely stiff carbon with soft kevlar, both materials not great at bonding with any kind of foam.
Hi tech $350 fins (C-3, Debotchet, Hurricane, Technlimitz, etc) for windsurfing are all airex blanked, fully shaped, carbon layups with one layer of outer wrap, some being made in halves. Carbon provides stiffness while retaining superlight weight, the airex is about 8lbs. / cu ft density and waterproof, and no kevlar used.
I think the best application for kevlar is still anti puncture, something not needed in fins. Kevlar gives lots, so would destroy the supporting foam if used on boards.
Hey ya Ben,carbon sands/grinds/foils great. It cuts supper clean and a little cooler I think.
Carbon next to glass is a little tough. The carbon doesn’t want to grind, and at the edge of the layer it is real tough to get a good foil ie: wear away the carbon without taking too much glass.
Not a problem with all carbon stacks.
Carbon/epoxy is about 5 times stiffer than glass/epoxy, which is about twice as stiff as polyester/glass.
Kevlar is used alot in touring kayaks due to the characteristics mentioned by LeeDD. It may be appropriate in certain conditions for a board. i.e. a traveling board that had kevlar as an outer lam. That would better protect it during travels I think.
Quote:Hey ya Ben,
carbon sands/grinds/foils great. It cuts supper clean and a little cooler I think.
Carbon next to glass is a little tough. The carbon doesn’t want to grind, and at the edge of the layer it is real tough to get a good foil ie: wear away the carbon without taking too much glass.
Not a problem with all carbon stacks.
Carbon/epoxy is about 5 times stiffer than glass/epoxy, which is about twice as stiff as polyester/glass.
all carbon [?graphite/ fibre?] stacks sound interesting…
Who here has done fins of these…Blakestah ? LeeDD ? Halcyon ? Tom@ ? Lokbox / JJR ?
Apart from ?extra $ cost? in materials, what do people think would be any other disadvantages…[the stiffness would be an advantage, to my mind.]
Greg Loehr ?
Bert ?
LeeV ?
Wildy ?
Aquafiend ?
anyone else ? who may have worked with carbon fibre / graphite [ are these the same by the way, or is there a slight , or BIG difference?] combined with epoxy resin…
I’d be really keen to hear some feedback on the advantages and / or the difficulties / shortcomings of doing solid carbon fibre fins.
thanks people for your information so far.
I think we have a wealth of resources and expertise in the ‘composites’ field represented on this forum. I for one am glad of the freedom and helpfulness with which people share this information, which I am sure for many has been hard fought and researched…thanks again !
ben
Of all the fins I’ve made I’ve never made a solid carbon lay-up. That said, I have sanded a lot of solid carbon lay-ups, and as the others said, it’s sands really well but is hard on sandpaper and or grinding discs.
It will be extremely stiff, if that’s what you want, and with care you can sand the stuff to a razor edge, but that’s all a bit unnecessary.
One really good reason I wouldn’t make a fin this way is the cost, not the actual cost, just the cost of the carbon dust you will be grinding off when you are foiling, waste of time and money.
Something I never did, but thought about, was to lay-up 5-6 layers of carbon in the middle of a normal glass lay-up. It would add some stiffness, particularly to the edges and tip, and with pigmented glass layers and foiled properly I imagine would look pretty good.
If it’s the aesthetics of the carbon you want, moulds are the obvious answer.
Anyone had try to make fins with acrylic plastic(clear like glass plastic)???
I’m thinking to try to make some for my fish but i dont know if acrylic plastic can be sanded to foil the fin…
Thank you all…