Death of the 3D Printed Fin

2014-11-25 Broken FinThe title and image says it all.

I’m amazed the fins have lasted this well being the very first test (approximately 15 hours of use). I don’t actually know how this happened (possibly 1 of my massive stacks!), it wasn’t until I was packing up my gear that I noticed. But as expected the screw holes were the weak point, with the stresses mentioned in a previous post always a concern.

I may look at thickening the profile slightly and taking a small amount of material out of the holes as there was plenty for the screws to bite into. But for now I have a spare printed and ready to go. No time to rest with perfect weather at the moment!

If you download my file from Thingiverse here let me know how it works for you ๐Ÿ™‚

– Posted by James Novak

11 thoughts on “Death of the 3D Printed Fin

  1. Hi James!
    Somethig wrong with your .stl file.
    Cura didn’t slice it.
    And RepetierHost has error:
    “The object is not manifold. This essentially means, that it is not watertight. This normally causes problems during slicing, resulting in unwanted details….”


      • Thanks for letting me know Leo. I’m honestly scratching my head to work out what might be happening on this one – the fin is modeled as a simple lofted solid using Solidworks, and any checks I run on both the native part file and the STL say there are no gaps or errors. And of course I can 3D print this file without any problems using the Up! Plus 2. I have also uploaded the file to Shapeways just to see if their software picks up any initial errors, but the file has passed these initial checks. When your errors come up do they show where in the model this is occurring?


    • Hi Leo, I’ve just opened the STL file in Cura and had no errors. Everything looks good and I can successfully export the Gcode ready for printing. Without having a compatible printer I can’t do much more than this, and can only assume that the file will print. Perhaps there is just some glitch with your STL file when it downloaded from Thingiverse? Maybe try downloading it again? Otherwise I really don’t know!


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  3. Hi, i have printed your fin design. It was really good at the beginning. After a while some fins had a problem with connection holes. And also the material can not resist for a long time against salty water, sun and dynamic forces.

    I have also designed 35mm fins and using them. What i am planning to do is, use embedded nuts and use a different material than PLA. Maybe coating can be applied too. A paint which can resist against sun and salt.


    • Thanks for the feedback and suggestions. I think embedding nuts in the print is a great idea to improve durability. Also, there are many materials that would be worth experimenting with – I’ve just started printing surfboard fins in carbon fibre reinforced nylon, which would also be great for kitesurfing. PETG could also be worthwhile. Keep me posted with how you go!


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