3D printing large surfboard fins

I think I better start a new thread with a more appropriate title, because I have clearly moved on from my attempts to cast 'hybrid laminated fins'.
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3D printing fins from PLA has turned out to be possible after much experimenting, although only longer term real world surf testing will conclusively show if the mechanical strength of the 3D printed PLA fins is sufficient. And the fins would likely deform if left in a hot car in Summer.
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See http://www.swaylocks.com/forums/casting-hybrid-lamination-fins for the lead-up to this 3D fin printing adventure.
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Also see: https://shop.prusa3d.com/forum/print-tips-slic3r-settings-kisslicer-model-repair--f12/printing-a-large-surfboard-fin-t2675.html and http://www.swaylocks.com/forums/discussing-wavegrinder-scientific-fin-design and http://www.swaylocks.com/forums/finfoil-v11-released for more details.
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The 3D printed fins are getting more consistent and also more colourful, because I'm using up the small amounts of PLA filament left on spools that don't have enough on them to print an entire fin. This leads to the nice side effect that it is possible to make fins that are identical in shape and properties, yet every single fin can be unique due to practically unlimited colour combinations.
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The fins shown are high aspect ratio fins with leading edge tubercles and an Eppler 168 foil.
The fins are printed solidly from PLA on an Original Prusa I3 MK2 3D Printer, built from a kit. The newer version is the MK2s: http://www.prusa3d.com/
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The idea to use a high aspect ratio fin came from the 'Wavegrinder fin' http://finsciences.com/surfboard-fin-science/, whose maker got the idea from multiple examples of high aspect ration foils that are in use almost everywhere where high lift and minimal drag is required, and where a scientific approach is used to optimise the lift to drag ratio.
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I got the idea to use tubercles on the leading edge of fins from Roy Stewart, who was to my knowledge the first person to 3D- print tubercled surfboard fins. http://www.roystuart.biz/2015/07/how-do-whalebumps-work-on-fins.html
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A quick internet search will show you that a lot of research into tubercles has been done in the last 10-20 years, initially spawned by interest in why humpback whales have tubercles on their flippers. Leading edge tubercles are being used or investigated for use in many applications, from rudders to keels to fans, propellers and wind turbine blades. A good overview can be found in this thesis by Kristy Lee Hansen: https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiV4J2JzMzVAhWCjpQKHV8gBf4QFggrMAA&url=https%3A%2F%2Fdigital.library.adelaide.edu.au%2Fdspace%2Fbitstream%2F2440%2F79211%2F8%2F02whole.pdf&usg=AFQjCNG8wevJcNr2BSWqaFfMU8Xl9v2x0A
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The idea to use a snap-in fin base came from using a snap-in McCoy Gullwing fin with 'Effect System', which is unfortunately no longer being manufactured. After I accidentally lost the fin in the surf, I found out that I could not buy a new one, so I decided to make my own snap-in fin system.
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The UTFB (Universal Tough Fin Base) is my own concoction and incorporates several features that are unique as far as I know. It can be used as purely snap-in fin, with no pin or screw holding it in the fin box. This should make the fin safer, because it allows the fin to be released from the box in a collision or if the surfer falls onto it in a wipe-out. The UTFB can also be used with a pin inserted at the forward end, which reduces the risk of the fin falling out of the box, but then it causes much more damage if a collision occurs, like the Effect System fins or standard screw in fins.
And, the fin can also be used as a 'traditional' screw-in fin, by inserting a pin at the aft end and using a standard screw and plate. A small part of the UTFB needs to be cut off for this purpose and the cut-off location is marked in the 3D print.
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The software used to design the fins themselves is finFoil http://www.finfoil.io/ Without finFoil, you would have to invent finFoil to make fins like this. It is an extremely useful program and amazingly easy to use.
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The UTFB was designed using OpenScad, and the 3D printing .gcode files were created using Slic3r Prusa edition.