I been making some 70's style twinfins and want to play with a quad set-up. Only thing is , 4 fins in solid glass seems to put too much weight on the tail of a real lightwieght board. Does anyone have a good system for lightweight ( and strong ) fins ?...................glass-on or removable
kayu, Keep an eye on the skegs I am makeing . They are redwood and balsa and can be glassed on or made with tabs.
arnt they skags
Glass can be heavy but design will give you lift so weight will be forgoten about in the water. Timber can be too stiff but a combo of light weight core, wood then glass is what i am bouncing around in my head. But ideas are ideas.
I love using these wabber designed fins i made in king billy pine and carbon. But i now use the glass versions on my timber board they have more twang.
I am far from an expert just what i have been told. Have a chat to a fin man. Are you in Aus?
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arnt they skags?
[/quote]
Nope,skags are girls you DON'T want to be seen with in public!
Featherweight Balsa Quads…
4 layers of 4oz. e-cloth on all sides…
Cedar and Basswood…
4 layers of 4oz. e-cloth on all sides…
Cedar and Basswood…
4 layers of 4oz. e-cloth on all sides…
Poplar Plywood…
4 layers of 4oz. e-cloth on all sides…
More fins here >>> paul-jensen-fins
Bamboo with two layers of 4 oz, each side, 1/8" carbon rod in the tabs going up about 1" into fin. Just had them out in some sizeable surf and no problems. Very light.
Working wood into the composite construction is certainly one of ways to lighten up fins. I’ve used it and it in conjunction with just fiberglass cloth and incorporated carbon in the composite as well with some interesting results.
Using just carbon fiber and fiberglass with epoxy resin also makes for a thinner panel (about 15% with the same number of glass layers) than a poly panel. So naturally the fins will be lighter as there is less glue in the lay up. Wtih carbon placed strategically in the stack one can get flex patterns and adjust rebound speed through a greater range than with fiberglass~polyester. Wood also figures in to the lightness, rebound, strenght picture of course but the bottom line is that epoxy give the fin maker a much wider range to tune performance through.
With this said many surfers prefer the beauty of poly. The stuff is water clear and unbeatable when it come to cosmetic appeal for solid glass fins.
There are ways of building wood fins that result in a very nice looking product. I’m working on how the flex picture will work out by using wood in different ways. At present bamboo is the best choice I have on hand though palownia may also play into the picture. I wont use poly with wood as this type or resin though very atractive is rigid thus defeating the natural flexibility of wood and the stuff makes lousy glue.
For very light large singles a high density foam core works very nicely with a glass spine and shell. I’ve done this before and it produces a very nice (though labor intensive) product.
Happy New Year, Rich
Greenlight Brian is working on some bamboo/carbon fiber panels right now. His earlier work with just babmoo had some issues that he’s trying to address. Maybe he’ll chime in soon, but that seems to be the direction the trend is heading for those who know the material science end of things. I’ve always used ply, with poly or epoxy and standard E glass. LIght, strong, cheap, easy to foil, and makes a fin with a good flex pattern.
Sandwich together Wood + G10 + Wood.
I recently posted a thread about using 1/16" G10 + mahogany.
http://www2.swaylocks.com/forums/g10-mahogany-fins
I liked this process because it was fairly simply to lay-up all the pieces.
I didn't weigh them, but the finished fins felt about the same weight as the plastic fin that I used as the template. I glassed them onto my board with Bill Thrailkills method of layering fiberglass pieces cut on the diagonal bias (no fillets needed). They turned out to be pretty strong. I tested them in some surf with 6-8 foot faces the other day, and they worked well.
I guess the only drawback is the fact that the G10 is green, and not clear -- like poly resin. Personally, I think it looks fine.
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Thanks , plenty of good info there ! Carbon will be used..........the trailers are the main drivers , so I'm thinkin glass-in trailers and removable front fins . That way I can still have a twin-fin.......
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kayu, Keep an eye on the skegs I am makeing . They are redwood and balsa and can be glassed on or made with tabs.
[/quote] .......W.O. , I got solid wood blocks right through the board, so a mortise & tennon may be just the thing !
sorry bill just recalling that thread from a little bit ago. women like that is Aus are known as scraggs
no drawback from my point of view swied those fins look sweet. wood floats got to be good.
I’m planning on making some bamboo FCS fins, but I read that the screws eventually wear through the glass on the tabs and the wood absorbs water and rots. Any truth to this? I was thinking about cutting the wood like a glass on and adding solid glass tabs.
Yo Ghostshaper,
Certainly the grub screws in an FCS system will eat into wood and chew it up pretty fast. One could drill an over sized hole by say an 1/8" or so and fill it with cut carbon fibers, This might do the trick. It’s hard to say how strong the tabs will be if they are predominantly of a solid piece of wood. If the wood is done with layers of the veneer with glass fiber between the layers it will hold up fairly well. However I’ve made such laminated fins for the Future system and the surfer has overtightened the grub screw so much as to chew the front of the fin tab landing right off. Oh Joy!
I don’t know where the wood occurs in your fin panel but the best way to strengthen the tabs is with carbon fiber. The fiber needs to run up into the fin base somehow and should occur fairly central to the tab. Once you start grinding away the integrity of the glass weave as it runs continuosly through the tab and fin itself you begin to sacrifice a lot of structural integrity. So If the meat of the fin is wood you some serious work to do to keep the fin tabs attached to the fin. If there is a central spine through that runs through the fin and tab it will make for a very good basis for the kind of strength you need for the FCS system to work for you.
Happy New Year, Rich
yeah , I like Llilibel's system of puttin a carbon rod through the tabs and up past the base...Ive had centre fins (wood) snap at the base before, from lack of strength at the base