Chip,
Here are the fins, the balsa covered one will never see a board…too fat…just a first experiment. They weigh just 55 grams…very strong…very resistant to compression.The other pics are the new ones, much better foil…should be very light…we will see…
The stack went…foam-2oz-balsa-6oz…on each side…vacummed in steps…
*the last pic is two fins together…cores for the next set…
Interesting. Good, cheap way to play around with vacuum bagging and balsa.
I just scavenged a compressor out of my friends fridge he was throwing away. Still need to get the rest of the pieces to put together a bagging setup, but I’ve been trying to think of what I can play around with to test it out. Fins, hadn’t thought of that.
Too fat? You never know. Try 'em, sand them off if they don’t work.
Yeah, that is what I was thinking,didn’t want to tackle/screw up a board…so I started with fins. Bert B got me thinking as well with a comment about heavy fins…my last few sets were with wood…these will be stiff and super light by comparison…should be able to feel the difference.
Ia Orana Ocean,
Those fins look great. I don’t think that they are too thick!! I have a 6’ fish with keel fins that are almost a 1/2" thick
they work insane. If you ever get a chance to check out a Dolphin fin they are very thick at the base and I have seen those dudes jumping in and out of the water at 20 knots plus. Tom Wegner did an experiment with a glass fin in a box and a balsa fin foiled and glassed on. He said that the board with the balsa fin was faster and had a better feel. R&D !!! brah, you’ve done the development now do the research in the WATER !! that is where you make the call of yes or no.
Ralph, Poe Rava
Oceans23, looking at your pictures some more got me thinking. In regards to wood grain and glass weave directions. Say your really like that template, you could try variations in flex by re-orienting the grain of the balsa and glass. For example, you’ve got the grain running fore-aft, you could try a set with the grain running 45 degrees, or 90 degrees. Or 45 one way on one side, and 45 the other on the other side. Same with the glass weave. You could alternate inner glass and outer glass by 45 degrees to make the flex pattern different.
That template wouldn’t be real sensitive to it, but what I have in my mind would. Sometimes it just takes a new perspective to open up other ideas. Thanks.
From that last shot the foil on those looks pretty good. I’d clean 'em up and ride them. I was looking at a friends early 80’s thruster the other day and the fins were noticeably thicker than what we’re used to today. Perhaps things will come full circle again.
Guys,
Some of the fastest boards I ever made had 3/4" thick foiled wood fins. I got pointed in that direction in 1960 by Phil Edwards. They really do work well.
Thanks heaps for posting those shots, Oceans !
Did you shape / foil them with a sanding block ?
cheers !
ben
PR…thanks…I am going to try em anyway! Its not rocket science right?
Lawless,
I agree you may not feel the changes you mentioned with a large area(no flex…) fin like these. Maybe I’ll try a vertical grain(balsa…) on the thinner set…and see if I feel it. I have two very similar boards I am building and decided to use the thicker ones as well…and see how they go…worst that can happen is I grind them back off.
BT,
Thanks for the input, your experience counts a ton. Again, thanks.
Chip,
Your welcome. Yep, a hard block to get the angles, then a dense foam block and paper to get the curves needed. Cheers …and have fun…
… and, was that epoxy resin you used on the balsa stack ones, ‘Oceans’ ?
It looks a bit lighter coloured than the ones I’ve made [but I guess that could just be the balsa].
Gray Murdoch’s and Hicksy’s wood fins I saw in person recently looked a more yellowy colour. They epoxied the ply, mine were darker… I used polyester resin…
ben
[ p.s. - MY fins are thicker than most F.C.S. thruster sets. I like them that way . ]
… yup, Resin Research epoxy. The epoxy is gin clear and dries that way too, I have heard(not seen…never used…) that other epoxy systems are a bit more yellow. Yes…filler coat…sand them smooth…glass 'em and ride!!! Have fun…