Reading through old threads about fin design on Swaylocks, it has just dawned on me that my attempts to 3D print large single fins are hampered by the standard fin box size.
Kayu mentioned a few years ago that he thinks the fin boxes should be about 1.5 times wider to allow for better foiling of fins.
Many experienced shapers insist that thicker foiled fins work better, at least in some conditions.
Fins of marginal strength break off just above the entry into the 9mm wide standard longboard fin box, at just the line where the foil thickness is suddenly reduced to accommodate for the narrow size of standard fin boxes.
A fin box with a wider slot would make it much easier to make thick fins that are less prone to snapping off. This would apply to 3D printing as well as wooden fin making and all sorts of hybrid methods.
I have leaned a fair bit about 3D printing with polycarbonate based materials and nylon materials during my failed attempts to print a large fin; based on this experience I’m confident that I could print a sturdy single fin box with an acceptable amount of warping. The warping would likely be inconsequential because it will get sanded off, or it might even fit in nicely with the tail rocker of the board.
Nylon may be unsuitable because resin is less likely to bond well with it. I’ll test resin adhesion to Polymaker PC Max and Taulman Nylon once I finished typing this.
Questions:
- How wide do you think the slot in the box should be? I suggest 15mm to 20mm.
- How long should it be? Same length as existing boxes would probably make sense.
- Does anyone have a CAD file or STL of an existing single fin box? Many links on the web claim they offer fin box files, but they are usually adapter inserts, not actual fin boxes.