I think long term, low maintenance, durable wood fins need to be covered with fiberglass and have a halo. With CNC perhaps they can be machined twice, once a bit thinner than the intended final thickness, then vaccuum bag a few layers of fiberglass on both sides\ down the fin tabs, then run it through the CNC again set to final thickness......A lot more work, but a lot more reliable too.
I am 95% sure this is how Hans makes his fins. He doesn't go back and run them through the cnc at the end though. Vacuum bagging with eopxy and glass gets it pretty close to final shape and running it through the cnc again can lead to mistakes if it isn't perfectly aligned. At least that's what I gathered from messaging him about it.
Has anyone tried making a traditional fin outline with tubercles and a modern foil? I know Mr. Mik made some when he was prototyping his g-whale fin, but it seems like he gave them up and was focusing on the g-whale. I've been thinking about rasta style keels with a few tubercles on the front and an 80/20 foil for use as either a twin or quad. Any opinions on something like that?
I tried one of MrMik's Harftub fins with tubercles that general size nearer the tip, and kept thinking I was dragging kelp and weed, though I was not. I kept checking after each ride, sure there would be a big glob of it.
No idea if my experience applies to a flat sided thruster fin with traditional outline.
Well there's plenty more in the quick and dirty prototyping stage.
...
2- Plain spitfire planshape thrusters, 2% camber. Two choices of central, the big one can be used as single with the side-bites.
...
It seems that your 3D CAD design process leads to a different surface undulation pattern compared to the fins I make using Hans' finFoil program.
I might be wrong, hard to see in the photos, but particularly the photo of the Spitfire fins looks like the thickest part of the foil is behind the tubercles and it remains the thickest part until all is the same thickness at the trailing edge.
The fins made with finFoil (and also the 'BLEF' fins made by Roy Stewart a few years ago) show a different undulation Pattern. I have no idea which one is better, or maybe it does not even matter.
With finFoil designed tubercled fins, you get the thickest part of the foil behind the valley. Behind the tubercles, there is a concavity.
I hope the screenshot shows clearly enough. It would be most interesting to compare 2 otherwise identical tubercled fins with these different surface undulation patterns.
I worked a lot on that, found 3 methods. One is to design a foil for each trough that has the thickest point at the same place as the preceding peak in the tubercled curve. It is time consuming but you get a fin that is smooth after it's thickest point. Another is to use only two foils but make sure that the peak foil has its thickest point further back than the trough foil. Last method is to use only one foil. This one leads to valleys that meets at the trailing edge, although visually they blend before that. None of these methods have a depression behind the peaks. Not sure if a surfer would feel the difference but the whale doesn't have them so I don't want them.
The pics shows thickness maps of the first two methods, and a screenshot of the third method.
We're getting very specific, may be we should not do that in this thread.
I took the liberty to redesign the Gullwhale 7 with only the E168 foil. I can send you the file if you want to have a look. The thickness map has artefacts that are not really there, takes time to have a smooth one. If you want me to try anything else let me know.
I took the liberty to redesign the Gullwhale 7 with only the E168 foil. I can send you the file if you want to have a look. The thickness map has artefacts that are not really there, takes time to have a smooth one. If you want me to try anything else let me know.
Metal to wood bonding for non-structural applications may be done successfully with epoxy providing that the metal is clean and bright. Don't pot stainless steel bolts in any epoxy resin if the application will be around water. Stainless steel works only in the presence of sufficient oxygen. The epoxy will deprive it of oxygen causing crevice corrosion in the presence of an electrolyte like seawater. Stainless steel fastener failure occurs where the bolt emerges from the epoxy resin.
I've had this occur, and it caused water to wick up the screw into the wood fin. I was able to pull it out with my fingernails and a bunch of rotten wood dust and paste came out with it.
If you use Stainless inside the wood, make sure the screw's head is submerged as well, not just the threads.
I've got some stainless in The purple 0.5 AW fin. Tapped and threaded for SS machine screws with submerged heads. Will report back if it proves troublesome in the future.
Anyway be warned Stainless steel, is not perfect for this application. Perhaps titanium :)
Man you guys are awesome. I feel like everyone here is way more invested in the survival of these fins than I am. I made these all as tests to see if the cnc process can be used to make fins relatively easily and to play around with some weird fins. I've read Mr Mik's journey designing the whale fin several times and despite not yet riding one, I am stoked to just try it out. Even if it breaks. The plywood ones I expect to break, the plys held too many secrets until they were machined. I also switched to hard wood because I ran out of conveniently sized plywood. I don't think the cherry one will break because it feels pretty sturdy, we don't have kelp to deal with, and I am not a hard turning machine. I've only ever broken one fin, my second home made attempt and it was more due to poor design and poor craftsmanship (my glassing sucks).
Ideally I think I am going to try to mimic Mr. Mik's dual screw fin base, with a few material differences. I keep thinking a solid fin with a wood core base, surrounded by thickened resin, machined out, and then the whole thing glassed with a layer or two of whatever cloth I have laying around.
I also want to work in Hans halo method.
I also really dig the engraved logos, pictures, sayings, and names on the sides. I'll probably try Hans thing with cutting out an inlay and filling with matching resin. My wife also wants me to do a live edge river fin, like the tables that are so fahionable these days.
I am ready for the weekend, the cherry fin should be surfable, there is a swell coming, and most importantly I don't have to work!
The plywood ones I expect to break, the plys held too many secrets until they were machined.
Yeah that's why it's worth to use the high grade plywoods. I also had issue with the cheap plywoods warping due to internal stresses getting released during machining. A good machine strategy can help to keep it flat while machining, but you'll end up with twisted fins.
The high grade plywood is much more predictable! Sometimes a knot surfaces, but that gives it some character.
phillipjohnw wrote:
I've only ever broken one fin, my second home made attempt and it was more due to poor design and poor craftsmanship (my glassing sucks).
You'll love vacuum bagging! Just throw some resing on the weaves, put a fin in between, just like making a drippy sandwich, throw it in the bag and magic happens!
phillipjohnw wrote:
I also want to work in Hans halo method.
I also really dig the engraved logos, pictures, sayings, and names on the sides. I'll probably try Hans thing with cutting out an inlay and filling with matching resin. My wife also wants me to do a live edge river fin, like the tables that are so fahionable these days.
And the great thing is, the method has structural benefits, it's not just cosmetic!
phillipjohnw wrote:
I am ready for the weekend, the cherry fin should be surfable, there is a swell coming, and most importantly I don't have to work!
Enjoy!
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finFoil: free fin designing software
http://www.finfoil.io
https://www.instagram.com/finfoil/
https://app.finfoil.io
I am 95% sure this is how Hans makes his fins. He doesn't go back and run them through the cnc at the end though. Vacuum bagging with eopxy and glass gets it pretty close to final shape and running it through the cnc again can lead to mistakes if it isn't perfectly aligned. At least that's what I gathered from messaging him about it.
Has anyone tried making a traditional fin outline with tubercles and a modern foil? I know Mr. Mik made some when he was prototyping his g-whale fin, but it seems like he gave them up and was focusing on the g-whale. I've been thinking about rasta style keels with a few tubercles on the front and an 80/20 foil for use as either a twin or quad. Any opinions on something like that?
https://3dprint.com/219790/uow-3d-printing-surfboard-fins/
I tried one of MrMik's Harftub fins with tubercles that general size nearer the tip, and kept thinking I was dragging kelp and weed, though I was not. I kept checking after each ride, sure there would be a big glob of it.
No idea if my experience applies to a flat sided thruster fin with traditional outline.
3DP-surfboard-fins-1.png
It seems that your 3D CAD design process leads to a different surface undulation pattern compared to the fins I make using Hans' finFoil program.
I might be wrong, hard to see in the photos, but particularly the photo of the Spitfire fins looks like the thickest part of the foil is behind the tubercles and it remains the thickest part until all is the same thickness at the trailing edge.
The fins made with finFoil (and also the 'BLEF' fins made by Roy Stewart a few years ago) show a different undulation Pattern. I have no idea which one is better, or maybe it does not even matter.
With finFoil designed tubercled fins, you get the thickest part of the foil behind the valley. Behind the tubercles, there is a concavity.
I hope the screenshot shows clearly enough. It would be most interesting to compare 2 otherwise identical tubercled fins with these different surface undulation patterns.
Screenshot from 2020-06-28 10-18-11.png
I hope I found a better way to illustrate the difference in surface undulations:
There is a continuous thickest part zig-zag line across the wingspan.
On the G-Whale fin (and other fins designd with finFoil and Roy Stewarts fins) that zigzag line is close to the front of the fin.
On WAO's fins, the line is much further back (maybe there is no such line on his fis at all, I'm not certain).
It like zig-zagging ridge of equal thiness along the wingspan.
G-Whale-Line_Screenshot from 2020-06-28 10-32-24.png
Spitfire-line_Screenshot from 2020-06-28 10-30-08.png
I worked a lot on that, found 3 methods. One is to design a foil for each trough that has the thickest point at the same place as the preceding peak in the tubercled curve. It is time consuming but you get a fin that is smooth after it's thickest point. Another is to use only two foils but make sure that the peak foil has its thickest point further back than the trough foil. Last method is to use only one foil. This one leads to valleys that meets at the trailing edge, although visually they blend before that. None of these methods have a depression behind the peaks. Not sure if a surfer would feel the difference but the whale doesn't have them so I don't want them.
The pics shows thickness maps of the first two methods, and a screenshot of the third method.
We're getting very specific, may be we should not do that in this thread.
Whale bumps thickness analysis, individual bumps and throughs 10.5 max thickness.jpg
SFS-B100D175S00MT6.jpg
Spitfire tubercled sidebite.jpg
_____________
We Are One
I took the liberty to redesign the Gullwhale 7 with only the E168 foil. I can send you the file if you want to have a look. The thickness map has artefacts that are not really there, takes time to have a smooth one. If you want me to try anything else let me know.
Gullwhale 7 E168 thickness.JPG
Gullwhale 7 E168.jpg
_____________
We Are One
Wow, phantastic!
I started a new thread: https://www.swaylocks.com/forum/109041/how-to-design-and-make-humpback-w...
so we can go as nerdy as we like.
And I'm looking forward to this! But first I need to go for a surf, this has the potential to stuff up my exercise regime.....
Regarding Stainless steel screws and Epoxy:
https://www.jamestowndistributors.com/userportal/document.do?docId=221I've had this occur, and it caused water to wick up the screw into the wood fin. I was able to pull it out with my fingernails and a bunch of rotten wood dust and paste came out with it.
If you use Stainless inside the wood, make sure the screw's head is submerged as well, not just the threads.
I've got some stainless in The purple 0.5 AW fin. Tapped and threaded for SS machine screws with submerged heads. Will report back if it proves troublesome in the future.
Anyway be warned Stainless steel, is not perfect for this application. Perhaps titanium :)
Man you guys are awesome. I feel like everyone here is way more invested in the survival of these fins than I am. I made these all as tests to see if the cnc process can be used to make fins relatively easily and to play around with some weird fins. I've read Mr Mik's journey designing the whale fin several times and despite not yet riding one, I am stoked to just try it out. Even if it breaks. The plywood ones I expect to break, the plys held too many secrets until they were machined. I also switched to hard wood because I ran out of conveniently sized plywood. I don't think the cherry one will break because it feels pretty sturdy, we don't have kelp to deal with, and I am not a hard turning machine. I've only ever broken one fin, my second home made attempt and it was more due to poor design and poor craftsmanship (my glassing sucks).
Ideally I think I am going to try to mimic Mr. Mik's dual screw fin base, with a few material differences. I keep thinking a solid fin with a wood core base, surrounded by thickened resin, machined out, and then the whole thing glassed with a layer or two of whatever cloth I have laying around.
I also want to work in Hans halo method.
I also really dig the engraved logos, pictures, sayings, and names on the sides. I'll probably try Hans thing with cutting out an inlay and filling with matching resin. My wife also wants me to do a live edge river fin, like the tables that are so fahionable these days.
I am ready for the weekend, the cherry fin should be surfable, there is a swell coming, and most importantly I don't have to work!
Yeah that's why it's worth to use the high grade plywoods. I also had issue with the cheap plywoods warping due to internal stresses getting released during machining. A good machine strategy can help to keep it flat while machining, but you'll end up with twisted fins.
The high grade plywood is much more predictable! Sometimes a knot surfaces, but that gives it some character.
You'll love vacuum bagging! Just throw some resing on the weaves, put a fin in between, just like making a drippy sandwich, throw it in the bag and magic happens!
And the great thing is, the method has structural benefits, it's not just cosmetic!
Enjoy!
finFoil: free fin designing software
http://www.finfoil.io
https://www.instagram.com/finfoil/
https://app.finfoil.io
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