does epoxy trap more air bubbles than poly? i was told by a guy at industral plastics and paint that when drying epoxy. you run a torch at low flame over the surface and it pulls any air bubbles out. does this make any sense?
Very nice! The carbon looks cool on the inside, will stiffen it up a ton too. How thick is the wood core?
Seems like alot of glass unless the core is really thin.
If you wax your formica surface with a few coats of auto wax you won’t need peel-ply. Once the epoxy cures you can just pop the fins off clean.
Word of advice, make sure and drill the recess holes into the fin tabs for the FCS plugs. I didn’t do it on my first set and screwing the fin screw into the FCS tab cracked the glass and created a stress riser and I broke one of the fins off. Both fin tabs were still in the box, they just split right above the screw. Next set I drilled a small recess into the wood core then when I glassed it just let it pool with resin. Then when the fin was done I just used a drill-press and put a small recess into that resin pool.
Here’s a shot of my first set:
These are the ones that broke, but I’ve made a few more that have worked quite well. Great flex, and they are LIGHT!
Making a set now that is 3/8" thick with a concave inner surface. Good way to experiment for cheap.
they look great but you may want to consider some fin rope along the leading edge. the beefed up front edge will keep the wood dry when you nick the fins… also i found with the wood tabed fcs fins you need to beef up the tabs where the screws set in. again to keep water out of the wood…
great work thought. the carbon and the wood is like past meets future…
Lawless- in the first set I used 3mm core, this is what I had at home.
I had to use 7 layers of 6oz on each side to get to the desireable thickness (6.23mm).
the fins went out much stiffer yet lighter than the original FCS.
75gram VS. 67gram....
on the next set of fins I decided to learn from my mistakes so I bought 5mm plywood
this will require not more than 2~3 layers on each side. maybe this way , there will be more flex.
thanks for the waxing advise, actually i did wax the formica surface with Johnson-wax but
I didn’t want any wax residues on the fin , which later might ruin the hotcoat. that’s why i used peelply.
.
jjp- as u said very nicely- past meet the future…hmmm , no! past meet the FCS
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KeithMelville - thanks for the warning, I like my eyes never want to lose them …
Got a question about the tabs. Isn’t one of the benefits of FCS that the fins will snap if overstressed rather than ripping out the fin plugs. Seems like making the tabs out of wood would prevent this from happening. Other than that your fins look really cool. How do you determine your foil? I work at NASA and I know that many of the newer fin foils come from data from our critical wing air flow studies from like the 50s. Not sure how you can do that kind of stuff by hand but the symmetry of your ply lines is pretty good.
I also work at the aircraft industry . as a UAV instructor and as a composite workman.
I am aware of the importance of a accuracy in airfoils, that’s why my first fin project was
making a mould out of original FCS fins. I’ve seen many guys here foiling their own fins by hand, using the plies as an idication to maintain a relativly good foil.
I made thickness measurments on the G-AM fins before I foild my own, tried to be as
close as possible to the original foil. now, I’m not saying I a hotshot! just a begginer with a “begginers luck”. I’m also not such a good surfer . not to mention the shitty waves in israel, that’s why I don’t really feel the big differences in foils.
If it works… I’m happy.
I not… still happy.
as I said from the begining of this fin project- I just want to try new different stuff.
If you have any tips for me, I’d be more than happy.
